Conference Report—The 2nd International Conference on Green Aviation (ICGA 2025) ^†

Abstract

The 2nd International Conference on Green Aviation (ICGA2025) was structured with one plenary session and nine parallel forums. More than 130 scholars and industry leaders worldwide were invited to present their latest research and insights during the conference. Over 90 authors submitted abstracts to it. The accepted papers will be published in the conference proceedings. To share and disseminate knowledge on green aviation, the abstracts and summary report of the invited speakers have been collected and are presented in the following conference report.

1. Introduction

It is with great pleasure that we present the proceedings of the 2nd International Conference on Green Aviation (ICGA2024), held from 6 to 8 November 2024, in the Eastern New District of Chengdu, China. Jointly hosted by the Chinese Society of Aeronautics and Astronautics (CSAA) and the International Association for Green Aviation (IAGA), ICGA2024 served as a global platform for advancing the development of green aviation through the exchange of advanced research, innovative practices, and policy insights.

This highly international conference brought together over 130 speakers from nearly 20 countries, alongside more than 400 representatives from industry, academia, and government. It witnessed an online participation of nearly 5000. The diversity of participants underscores the growing recognition of the need for collaborative approaches to address the aviation sector’s sustainability challenges. Through a combination of plenary sessions, nine parallel forums, and three dynamic panel discussions, the conference facilitated a comprehensive exploration of key issues in green aviation, such as sustainable aviation fuels (SAF), eVTOLs, advanced materials, low-carbon airport operations, AI technology development, and policy strategies for achieving long-term carbon neutrality.

ICGA2024 engaged efforts from a series of education and research institutes, as well as companies, including Beihang University, Northwestern Polytechnical University, the Civil Aviation University of China, the Civil Aviation Flight University of China, Hefei Hangtai Electrophysics Co., Ltd., Zhonghang Shangda Superalloys Co., Ltd., the Science Center for Gas Turbines, the National Key Laboratory of Electromagnetic Information Control and Effects., etc. The event also received strong support from global organizations including the International Council of the Aeronautical Sciences (ICAS), the International Organization for Aerospace Industry Associations (ICCAIA), Airports Council International (ACI), the International Air Transport Association (IATA), etc.

In addition to formal sessions, ICGA2024 emphasized collaboration and partnership-building. The conference featured networking events and industry showcases, enabling participants to explore opportunities for joint innovation.

We extend our deepest gratitude to the sponsors, organizing institutions, and participants whose contributions were essential to the success of ICGA2024. We also acknowledge the efforts of the peer reviewers, who ensured that the research presented in this volume meets the highest academic and professional standards.

The ICGA2024 proceedings provide a record of the ideas, solutions, and strategies shared at the conference, reflecting the collective ambition of the global aviation community to accelerate its transition to sustainability. We hope that this collection will serve as a valuable resource for researchers, practitioners, and policymakers committed to driving innovation and sustainability in aviation.

2. Plenary Session—Key Note Speech

2.1. International Civil Aviation Environmental Protection Policies and the Green Development of Civil Aviation of China

Name: Fang Liu

Organization: Civil Aviation Administration of China (CAAC)

Lecture Summary:

The civil aviation is an important driving force for achieving global green development and has a significant impact on the realization of the United Nations Sustainable Development Goals (SDGs).

The International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations responsible for civil aviation, the most authoritative international organization in the field. It has been committed to establishing and implementing global standards. Aiming for a safe, efficient, economical and environmentally friendly global aviation system, ICAO has made remarkable contributions to the progress of human civilization. Today, environmental protection has become one of strategic objectives of ICAO. Its overall goal lies in the reduction of noise, emissions and greenhouse gas impacts, hereby ensuring the aviation being adapted to climate change. ICAO has actively promotes global aviation decarbonization through the Annex 16 to the Convention on International Civil Aviation, the Environmental Technical Manual (ETM) and relevant ICAO Assembly resolutions. It has advanced efforts in global coordination of aviation environment protection policies, standard-setting, development of clean energy, technical cooperation and financial assistance. Additionally, ICAO supports capacity building in developing countries through its No Country Left Behind initiative.

China, being a responsible major power, has been promoting green development in civil aviation. It has incorporated the carbon peaking and carbon neutrality goals into its national strategy, issuing documents such as The Outline for the Development of Green Aviation Manufacturing. It has revised laws, regulations, and standards to promote the green transformation of aviation. Efforts have been made to accelerate research and deployment of sustainable aviation fuel (SAF), to encourage airlines to adopt SAF, to guide enterprises in obtaining SAF airworthiness certification and to establish the aviation carbon market in an orderly way. Carbon emissions have been continuously reduced through enhanced air traffic management efficiency, improved flight performance, optimized ground energy structures, and pollution prevention measures. In addition, China has strengthened technological innovation, encouraging research institutes to participate in green aviation research and supporting industry associations to give full play to their roles. Furthermore, Civil Aviation Administration of China (CAAC) actively participates in global civil aviation governance, engaging in technical consultations under the ICAO Committee on Aviation Environmental Protection (CAEP), submitting and updating its National Action Plan, sharing experiences and practices in advancing green aviation transformation, and contributing Chinese solutions to the green development in global civil aviation. In the future, China will continue to promote green aviation development by fostering the research and application of SAF, optimizing airport energy structure and pollution prevention, improving the operational efficiency of air traffic management, and deepening international exchanges and cooperation.

In regard of green development for international civil aviation, the author presents the following ideas:

First, the stakeholders shall be united and international exchanges and cooperation shall be strengthened. It is crucial to enhance global collaboration among government agencies, the private sector, manufacturers, research institutes and international organizations. The cooperation shall adhere to the fundamental principles of international law and leverage the roles of ICAO, UNFCCC, and other international organizations. Developed countries should support developing countries in enhancing their green development capabilities. Additionally, associations such as the International Association for Green Aviation (IAGA) and academic institutions should be encouraged to establish international exchange and cooperation platforms to facilitate green aviation development jointly.

Second, innovation must be emphasized and international aviation environmental standards shall be developed. It is essential to advance the research and development in new energy sources, new propulsion systems, new aircraft configurations, and intelligent aviation technologies. Efforts should be made to establish international standards for airworthiness certification, sustainability accreditation, and environmental requirements for new energy aircraft. Moreover, it is important to define regulatory frameworks, streamline certification processes, and reduce certification costs to facilitate the adoption of green aviation technologies.

Third, new technologies for enhanced global air transport system efficiency shall be promoted. Countries may refer to ICAO’s data-driven decision-making mechanisms to accelerate the introduction and adoption of advanced green and low-carbon technologies. Supporting manufacturing and operating enterprises in their green and low-carbon transition will improve industry efficiency and help build a quieter, cleaner, and more efficient air transport system. It is important to enhance understanding among industry stakeholders, supply chain participants, and the public regarding aviation’s environmental impact, while facilitating the exchange of talent and information across countries and sectors.

2.2. Green Aviation Technology Revolution and the NextGen Low-Altitude Economy

Name: Rui Qin

Organization: Civil Aviation University of China (CAUC)

Lecture Summary/Abstract:

The low-altitude economy is divided into traditional low-altitude economy and the new generation low-altitude economy, of which the latter is a new stage of low-altitude economy brought about by the green aviation technology revolution. It is still in its incubation period. For low-altitude flight activities, the green aviation revolution has made distributed propulsion more affordable, quieter, easier to maintain, and with less emissions. Currently, many countries around the world and numerous enterprises are vying for the new generation low-altitude economy track, and there have already been dozens of low-altitude aircraft configurations and thousands of new-generation low-altitude aircraft types. In the foreseeable future, there will be several new generation low-altitude aircraft that will stand out and become classics, playing a role in many scenarios and influencing human transportation and urban function zoning.

3. Plenary Session—Invited Lectures

The Practice and Progress About Aeronautical Materials Recycled Application Technology at ZHSD

Name: Hongya Ma

Organization: Zhonghang Shangda Superalloys Co., Ltd. (ZHSD)

Lecture Summary/Abstract:

This introduction about the aeronautical recycled materials technology includes: equipments, recycle process and melting/remelting process, etc…, especially the qualification, specification and quality controls technology, as well as the industrial practice and future progress.

4. Track 1: Novel Aero-Power Forum

4.1. Hydrogen Production by Electrochemical Reforming of Ethanol for Engine Propulsion

Name: Germano Tremiliosi-Filho

Organization: University of Sao Paulo/Chemistry Institute of Sao Carlos

Lecture Summary/Abstract:

Hydrogen production by steam reforming of natural gas at high temperatures has contributed to the carbon emissions. Electrolytic hydrogen produced by primary renewable energy sources is free of carbon emissions, but it is a non-suitable way to produce hydrogen on board of a vehicle. This limitation can be overcome by a low cost and free-carbon emission technology of electrolytic hydrogen production assisted by alcohol oxidation, in substitution of oxygen evolution. Additionally, an important cost reduction in the hydrogen production by electrolysis, it is avoiding the employment of a membrane electrode assembly component (membrane less). Thus, here will be described the development of catalysts for hydrogen evolution reaction (HER) in alkaline medium (4 M KOH + 1 M ethanol at ≤85 °C). The measurements were made in an electrochemical reforming cell with electrodes of 6 cm². The catalysts were characterized by XRD, Raman spectroscopy, HRTEM and SEM. Tested materials: (i) MoS2 and (ii) Ni/B intermetallic compounds. The MoS2 was obtained by electrodeposition from (NH4)2MoS4 precursor on black pearls high area carbon matrix doped with nitrogen. The activity of MoS2 for the HER is similar to the Pt electrode and was not sensitive for ethanol reduction. The synthesis method used for preparation of Ni/B intermetallic were grinding the metallic components in a ball mill and heat treated under inert argon atmosphere according to the phase diagram. The Ni2B intermetallic showed an improvement for the HER in presence of ethanol, while the Ni3B was inhibited in ethanol.

4.2. Safety Measures in ATEX Zones: Addressing the Challenges of Hydrogen Utilization

Name: Ljiljana Medic Pejicv

Organization: Universidad Politecnica de Madrid (School of Mining and Energy Engineering)

Lecture Summary/Abstract:

In light of the growing importance of hydrogen as a key element in the energy transition, it is crucial to guarantee the secure utilisation of hydrogen within the framework of ATEX (ATmosphere EXplosive) regulations.

Designing a hydrogen system to meet safety standards is inherently complex due to several critical factors. Hydrogen’s low ignition energy, high reactivity, tendency to BOG, wide flammability limits, high burning rate and its colourless, odourless and tasteless nature contribute to its hazardousness. In addition, the high reactivity of hydrogen with other materials, the low density of the gas and its diffusivity aggravate these risks. Awareness of these potential drawbacks is essential to take early precautions and develop reliable prevention and protection systems.

This paper not only reviews the current state of hydrogen leak detection and prevention and protection measures, but also identifies the main knowledge gaps that need to be filled to improve safety. These gaps include a deeper understanding of hydrogen’s post-release behaviour in various environments (e.g., enclosed or congested spaces), its dispersion characteristics and its explosive properties. Filling these gaps is essential to refine relevant codes and standards, to develop safer engineered solutions and to enable new and improved technologies to emerge.

4.3. Magnetically Aided Direct Seawater Hydrogen Production

Name: Evangelos Hristoforou

Organization: National Technical University of Athens

Lecture Summary/Abstract:

A method for direct hydrogen production aided by magnetic and electromagnetic means is proposed. Magnetic field of 1 T amplitude, provided by Nd-Fe-B permanent magnets, is used to magnetically polarize the water molecules and particularly the hydrogen proton cations. In the same time, a bipolar electromagnetic pulse of 0.1 ms duration and +10 kA peak, applied by electrodes set in the seawater at a distance of 50 mm, is acting on the water molecule bonds. The current pulse is obtained by discharging a 10 F supercapacitor, made by cement and black carbon. This way, the H-OH bond is elongated and broken, resulting in a proton (H+) and a hydroxyl (OH-). A theoretical approach suggested that the elongation of H-OH bond can be as large as 2–2.2 nm. The measurements have been realized in a Teflon box supporting the hydrogen production. The produced hydrogen was measured in a Shimatdzu gas chromatograph. The results illustrate absence of other molecules except hydrogen, within the limits of uncertainty of the gas chromatograph. The energy required for the resulting hydrogen production equals 40–43 kWh per kg of produced hydrogen. The energy required for hydrogen production is 25% less than the energy required for alkaline electrolysis of drinkable water. Research is underway to search different modes of magnetic biasing and electromagnetic excitation to further decrease the energy required for hydrogen production.

4.4. Graded TiN Coatings Coated onto Aluminium Sheets to PEMFC Bipolar Plates Application

Name: Felipe Carneiro da Silva

Organization: Universidade de São Paulo

Lecture Summary/Abstract:

Growth population around the world have been increased very fast along two last centuries. Nowadays about 8 billion people live in the world and it will expected that this number rise to 10 billion near 2050. To supply the market and population necessities, obviously energy demand and consume will increase. To solve this problem, more efficient and cleaner energy sources should be developed. Proton exchange fuel cell (PEMFC) is an efficient and sustainable solution due to its fast start-up, low temperature, low noise, portable application and small size. However, the high manufacturing cost and mass of bipolar plates (BPP’s) are hinder its widespread commercialization. Nowadays, coated aluminum alloys with ceramic coatings such as graded-TiN obtained by GAMS technique are a potential candidate materials to solve this problem. Moreover, by adjusting specific deposition parameters, as substrate bias voltage, allows to produces more homogeneous and no voids coatings, improving the adhesion and increasing the corrosion resistance.

4.5. Hydrogen Propelled Aircraft—Why, What and How

Name: Michael J Pekris

Organization: University of Surrey

Lecture Summary/Abstract:

Sustainable aviation is one of the most challenging sectors to decarbonize. Yet, if left unaddressed compared to other industries, this could become the major carbon contributor as we approach 2050. Hydrogen has gained unprecedented attention as a future fuel for aviation, for use within fuel cell or hydrogen gas turbine propulsion systems. This talk discusses the advantages and disadvantages of hydrogen and considers some of the key on-board technology enablers of low carbon commercial flight for different aircraft mission requirements. Furthermore, the talk aims to provoke debate about strategies for derisking these technologies for future entry into service and supporting net zero, considering the uncertainties associated with environmental science and contrails, green hydrogen production and its availability at the point of use, and the safety and certification of the aircraft and supporting infrastructure.

4.6. H2 Gas Sensors: Its Scientific Foundations, IP & Commercialization

Name: Jung-Sik KIM

Organization: Beihang University

Lecture Summary/Abstract:

Solid oxide fuel cell technology is not only be developed for an energy device, but also could be utilized for a gas sensor. The report will share the insights of scientific progression for the gas sensor development led by Prof J-S Kim.

Abstract: In high temperature SOFCs (Solid Oxide Fuel Cells), the performance of the cell can be altered by the variation in the temperature distribution throughout the cell/stack. Conventional thermocouples can provide limited information depending its location in the system. The investigation utilized own developed a multi-junction thermal array (MCTA) sensor to read out the true temperature of the SOFCs whilst working. In this work, the sensitivity of MCTA sensor is assessed. It is directly attached to the cathode surface of the anode-supported SOFC to monitor the temperature of the electrode during temperature ramping, OCV changes during anode reduction. MCTA sensor based readings reveals an area-selected reduction process as well as the effects of direct oxidation on cell’s local temperature.

Beyond this point to exploit the sensor attached SOC, developed an electrochemical fuel cell based sensor for monitoring of gas contents such as hydrogen, in a hydrogen-natural (H2/NG) gas mixture to determine the calorific value of the H2/NG mixture. This device traces the hydrogen content within the (predominantly methane) stream, and provides an output current reading which correlates to the level of hydrogen in the stream. Present systems for inspecting gas composition to a necessary accuracy (eg. chromatography) are expensive due to their complexity and are not suitable for use in the field, which impedes their wider adoption. Kim and his group are looking to demonstrate an economical, robust and compact sensing platform which consists of H2 sensing and temperature sensing that can be deployed in point-of-use environments.

4.7. Thin Films and Hydrogels for Aviation Electrochromic Devices

Name: Agnieszka Joanna Pawlicka Maule

Organization: Chemistry Institute of São Carlos (Instituto de Química de São Carlos, IQSC), Universidade de São Paulo

Lecture Summary/Abstract:

Recent years have shown an increased search for new solutions to capture energy from natural and inexhaustible sources such as solar, wind, water, and geothermal. This is because fossil energy sources like oil, coal, and natural gas have limited reserves, and they also have a significant impact on our environment. The new solutions have been implemented, but still, there is a lot of interest, not only from academia but also from industry, in developing new materials that can be used in eco-friendly devices. Electrochromic devices (ECDs) are systems that can change color after applying small potentials, and they are already used in rearview mirrors for cars and airplane windows. They are also installed in some modern buildings to decrease the energy spent on air conditioning. The ECDs can have many different configurations and be obtained using many other materials. Nonetheless, their basic configuration is a sandwich made of electric, color change, and ionic conductivity coatings. These coatings are thin films of transition metal oxides or polymers, and they are deposited on transparent electrodes like ITO or FTO; between them, there is always an electrolyte that can be liquid, solid, or gel. Different thin films of transition metal oxides and the methods they are synthesized and deposited on the glass/ITO substrates are described in the literature. Doping pure metal oxides with other metals improves their electrochemical and optical characteristics. For example, thin films of V2O5 doped with ZnO have shown significant changes in the electrochemical stability, maintaining the redox peaks of the material, and have more effectively preserved the voltammogram area. The cyclic voltammetry of these films has also shown an increase in charge density values for the cathodic and anodic peaks that displayed the vanadium redox potential. The ECDs need an electrolyte, and many papers on gel polymer electrolytes tested in different electrochemical devices have been published already. These electrolytes are very promising because they provide good contact between the electrodes, do not leak, and if obtained from natural polymers or their derivatives they also are environmentally friendly. Furthermore, in the case of natural polymer-based electrolytes, a clay addition can improve their ionic conductivity values. In the case of sodium alginate with 5 wt.% montmorillonite clay that reached 2.77 × 10⁻³ S/cm² at 25 °C and 1.96 × 10⁻² S/cm² at 70 °C. In summary, thin films of transition metal oxides and natural macromolecules are still attracting attention because of their new application prospects including aviation industry.

5. Track 2: Sustainable Aviation Fuels (SAF) Forum

5.1. China’s Airworthiness Certification Policy and Sustainability Development for Sustainable Aviation Fuel

Name: Zhiyuan Yang

Organization: The Second Institute of CAAC

Lecture Summary/Abstract:

This presentation provides an analysis of the current development of Sustainable Aviation Fuel (SAF) both domestically and internationally. It introduces the growing importance of SAF in promoting sustainability within the civil aviation sector. In alignment with our strategic objectives, the presentation emphasizes two critical attributes of SAF: airworthiness and sustainability, both of which are essential for its application. It also presents international SAF approval models, with a particular focus on the airworthiness certification scheme of the Civil Aviation Administration of China (CAAC), alongside ongoing efforts in sustainability assessment. Additionally, it explores the challenges that SAF development faces and outlines potential future growth directions.

5.2. The European Union Aviation Safety Agency (EASA)’s Activities in the Field of Sustainable Aviation Fuels (SAF) and Its Contributions to International Cooperation

Name: TERMINET CEDRIC

Organization: EU-China APP (part of the European Union-North Asia Civil Aviation Cooperation Programme)

Lecture Summary/Abstract:

It is EASA’s expectation that SAF will play a role in fulfilling the vision of making Europe the first climate-neutral continent by 2050. EASA is committed to facilitate the uptake of Sustainable Aviation Fuels (SAFs) in the aviation industry.

As an aviation regulator, EASA is involved with the SAF approval process ensuring the associated airworthiness standards are met. In addition, the European Commission has envisioned a more active role for EASA in the context of the ReFuelEU Aviation legislative proposal aiming at increasing both supply and demand for SAF as proposed in the ‘Fit for 55’ package.

EASA’s International Cooperation activities are key in building the capacity to address the global environmental and sustainability challenges facing the aviation sector. EU funded actions are enhancing the relationship with partner states and providing sound technical understanding to facilitate their transition to sustainable aviation.

Available online: https://www.easa.europa.eu/en/light/topics/sustainable-aviation-fuel (accessed on 6 November 2024).

5.3. Practice and Exploration on SAF Life-Cycle Carbon Reduction

Name: Eason Chen

Organization: Tianzhou International Trading Group

Lecture Summary/Abstract:

The report first introduces the development history of Sichuan Tianzhou, including project progress in the SAF field. It points out that the aviation industry accounts for 2.5% of global carbon emissions and is growing rapidly, emphasizing the importance of Sustainable Aviation Fuel (SAF) as a low-carbon alternative to fossil based jet fuel. SAF is mainly synthesized from raw materials such as waste oils and agricultural, forestry, and urban waste, with a carbon reduction potential of up to over 80% throughout its life cycle. The report also outlines global hotspots for SAF, China’s civil aviation industry’s application plans for SAF, the main global SAF process pathways and their costs, as well as the announced SAF design capacities in the world and China. Finally, the report discusses strategies to tap into the carbon reduction potential of SAF from both the supply and demand sides, including expanding the scale of non-edible oil crop cultivation and the global SAF trading rules system, as well as the innovative model of decoupling physical SAF from its carbon reduction attribute.

5.4. Understanding Soot Formation in Combustion of Evolving SAFs

Name: Chih-Jen SUNG

Organization: University of Connecticut

Lecture Summary/Abstract:

Sustainable aviation fuels (SAFs) derived from renewable sources are promising solutions for achieving carbon neutrality and further controlling aircraft engine emissions, operating costs, and energy security. These SAFs, primarily consisting of branched and normal paraffins, exhibit significantly reduced sooting tendencies compared to conventional petroleum-based jet fuels, due to their lack of aromatics content. Since future fuels and engines will have to achieve very tight control of particulate emissions, a comprehensive understanding of particulate formation fundamentals is essential.

Carbonaceous particle nucleation in flames is one of the key challenges of combustion. Insight is lacking at many levels for transportation-relevant fuels, including chemical kinetics, reaction pathways leading to polycyclic aromatic hydrocarbons and their growth to soot. Moreover, the complex effects of fuel structure on soot formation are not fully understood, and the abilities of various sooting indices to account for such fuel structure effects on soot prediction have not been systematically examined over a broad range of fuel compositions and engine conditions. Hence, experimentally determined spatial distributions of sooting levels over a wide range of combustion conditions are still required for the development and validation of comprehensive chemical kinetic/soot models that can predict the combustion chemistry of different sustainable fuels involving soot formation.

The present investigation aims to provide insights into the soot formation of various ASTM-approved SAFs and their surrogate fuel formulation for the emulation of sooting characteristics. In addition, the suitability of binary fuel blends of iso-dodecane (2,2,4,6,6-pentamethylheptane, iC12) and normal-dodecane (n-dodecane, nC12) as a surrogate fuel for reproducing the sooting propensity of each SAF studied herein is assessed by comparing the measured soot volume fraction results of surrogate fuel and the corresponding SAF. Furthermore, soot volume fraction results as a function of blending ratio, varying from pure iC12 to pure nC12, were analyzed to illustrate the effects of fuel molecular structure, i.e., alkane branching, on soot formation.

5.5. Sustainable Aviation Fuel from Lignocellulos

Name: Chenguang Wang

Organization: Guangzhou Institute of Energy Conversion, CAS

Lecture Summary/Abstract:

Lignocellulose is a good feedstock to produce sustainable aviation fuel. We developed three method to produce aviation fuel from lignocelluose, aqueous reforming, Fischer-Tropsch (FT) from biomass syngas and alcohol to jet (ATJ) fuel by catalysis. For aqueous forming, a 1000 t/y demonstration system was built to test the feasibility, with a result that 10 ton of biomass can produce 1 ton jet fuel and 0.25 levulinic acid which is a fine chemical. With upgrading FT catalyst, a 150 t/y demonstration system is on the way. With the catalysts we developed, a 100 t/y demonstration system is under construction.

5.6. An Overview of SAF’s Scalable Supply & Commercialization

Name: Meiting Wang

Organization: Aviation Industry Development Research Center of China

Lecture Summary/Abstract:

SAF feedstocks, production pathways, and supply chains have continued to evolve in the last few years. It’s an ongoing sector of the sustainable aviation industry and it is expanding policy and regulation landscapes more than ever. This lecture presents an overview of SAF’s scalable production and supply. It also presents the latest updates and addresses concerns about the sector’s commercialization.

6. Track 3: Integrated Design of Materials and Structure Forum

6.1. Multi-Fidelity Full-Field Surrogates for Design Optimization

Name: Piotr Breitkopf

Organization: Université de Technologie de Compiègne

Lecture Summary/Abstract:

High-fidelity numerical models in Multidisciplinary Design Optimization (MDO) present significant challenges, including the complexity of coupling discipline-specific solvers, robust remeshing for shape optimization, and managing computational demands in high-dimensional design spaces. Surrogate-Based Optimization (SBO) helps address these issues, especially in Derivative-Free Optimization (DFO), where the goal is to find a global solution. However, SBOs often require extensive training samples, and inadequate sampling can lead to poor function representation or false optima.

To improve this, Multi-Fidelity Surrogate Modeling (MFSM) has become increasingly important in MDO research. While most MFSM techniques fuse scalar data with predefined kernel functions, there is a growing interest in physics-based approaches. These could potentially enhance precision and reduce computational costs in industrial applications by giving better insight into intricate local physical phenomena appearing at different scales.

6.2. Surface Mechanical Treatment: Effective Method for Lightweight of Mechanical Structure

Name: Vincent Ji

Organization: Université Paris-Saclay

Lecture Summary/Abstract:

Lightweight of mechanical structure contributes to the green manufacturing and the green aviation for aeronautic components, and to the reduce of energy consumption during service. Surface mechanical treatment process can increase effectively the durability of the mechanical components by introducing surface compressive residual stress and by surface microstructure modification; with surface compressive residual stress introduction and the associated microstructure evolution, surface mechanical treatment can also reduce efficiently the weight or thickness of treated components keeping the same initial design life.

The principal of classical process of surface mechanical treatment, such as shot-peening and ultrasonic peening, will be presented. The recent developed new technologies (dual peening, stress peening, laser peening, water peening) will be introduced and discussed.

6.3. On the Design and Mechanical Properties of Novel Modular Discrete Auxetic Honeycomb Meta-Structures

Name: Yilin Zhu

Organization: Southwest Petroleum University

Lecture Summary/Abstract:

Auxetic honeycomb meta-structures typically have complex artificial microstructures and require integrated production through additive manufacturing. Although additive manufacturing technology has made significant progress in recent years, structures produced by additive manufacturing are prone to being trapped in internal defects, rough surfaces, uneven microstructures, and residual stresses, which significantly affect the service performance of this kind of structures. Furthermore, the maturity of additive manufacturing technology still cannot compare with traditional manufacturing in many cases. Currently, it is still a challenge to manufacture low-cost auxetic honeycomb meta-structures with outstanding properties. Additionally, integrated structures are not sufficiently flexible in responding to engineering demands. Hence, there is a urgent engineering demand for the development of discrete auxetic honeycomb meta-structures that are not only cost-effective to manufacture but also capable of flexibly meeting various engineering demands. To address this demand, three types of modular discrete auxetic honeycomb meta-structures were developed. These designs are characterized by significantly lower crush stress and a more effective prevention of impact load transfer compared to their integrated counterparts. Theoretical models assessing the crashworthiness of these structures were established and thoroughly validated through finite element (FE) simulations and experimental tests.

6.4. Accounting for the Size Effect in Modeling the Behavior of Nanocomposite Materials

Name: Ludovic Cauvin ¹, Dang Phong Bach ¹, Delphine Brancherie ¹ and Djimedo Kondo ²

Organization:

^1. 

Université de Technologie de Compiègne, Sorbor Alliance

^2. 

CNRS Institut Jean Le Rond d’Alembert

Lecture Summary/Abstract:

Driven by the synergy of smart materials and weight reduction, nanocomposites are increasingly used. Despite their low reinforcement volume fraction, they exhibit exceptional mechanical properties due to the nanoscale reinforcement size, where interfacial phenomena play a key role.

Modeling the size effect in nanocomposites remains a formidable challenge. While micromechanical models incorporating interfacial effects have shown promise, they often face analytical limitations, especially for complex inclusion shapes and nonlinear behavior.

To address these limitations, we have developed numerical strategies based on representative volume elements (RVEs). Our approaches include interface elements, XFEM/level set, and embedded FEM methods. Key results from our studies on elastic and elasto-plastic behavior of nanocomposites will be presented in the talk.

7. Track 4: Aerodynamics Design and Optimization Forum

7.1. A High-Fidelity Wall-Modeling Approach for the Laminar Boundary Layer in WMLES Calculations

Name: João Luiz F. Azevedo

Organization: Instituto Tecnológico de Aeronáutica

Lecture Summary/Abstract:

The present talk discusses a possible approach for handling the very thin laminar boundary layer that develops near the body leading edge on external flows at high Reynolds numbers. Scale resolving simulations are becoming commonplace for addressing turbulent flows involving complex phenomena, such as those encountered near stall conditions on flight vehicles. The need for having acceptable computational costs, while still considering realistically complex configurations, indicates that the use of Wall-Modeled Large Eddy Simulation (WMLES) is the high-fidelity method of choice for handling such calculations. Therefore, WMLES has become the often-used technique for calculating turbulent flows with massive separation, where the usual Reynolds-averaged Navier-Stokes formulation approaches fail to provide adequate resolution of the relevant flow phenomena. However, even if the reference flow Reynolds number is high, there is a very thin laminar boundary layer near the body leading edge which has to be solved for. Estimates indicate that the costs of resolving this laminar portion of the boundary layer can render such simulations prohibitively expensive, due to the very stringent mesh refinement requirements needed to resolve the very thin laminar layer. In the present talk, an approach for addressing this problem is presented. The approach is based on developing a wall model for the laminar portion of the boundary layer, using concepts inspired on classical boundary layer local self-similar solutions, which can be implemented in a very similar way as WMLES wall models. The presentation highlights the efforts in analyzing the proposed model characteristics, by addressing flows over a NACA 0012 airfoil configuration at subsonic flight conditions and looking at the behavior of pressure and skin friction coefficients, as well as some flow topology visualizations. Some fundamental aspects of the proposed model are investigated by studying the effects of the wall model height parameter, which is a key element in WMLES calculations. Mesh refinement and other numerical characteristics of the solutions are also investigated. The results demonstrate that the model can yield solutions which are quite independent of the assumptions leading to the specification of the behavior of the wall model height parameter. In summary, the present results are very encouraging as good agreement with fully-resolved, reference solutions is obtained. Hence, they demonstrate the feasibility of the use of the proposed model for the laminar flow portion of an otherwise high-fidelity turbulent calculation.

7.2. Extension of a DG Method with h/p Adaptivity and Sub-Cell Resolution for Airframe Noise Generation and Propagation

Name: John Ekaterinaris

Organization: Embry—Riddle Aeronautical University (ERAU)

Lecture Summary/Abstract:

High-order discontinuous Galerkin (DG) methods developed in the last three decades have emerged as an attractive alternative for numerical simulation of complex flows and they have been extended to other fields, such as electromagnetics and MHD. The DG method is a mixture of the finite volume (FV) method, using a numerical flux at the element interfaces, and the finite element (FE) method, using local expansion of the numerical solution within the element. The FV context of the DG method provides local conservation and stable discretization of the convective fluxes. The FE context endows the DG method with a strong mathematical foundation that can be exploited for error estimation and mesh adaptation (h-refinement), and for adaptive local increase of the order of accuracy (p-refinement) as well as h/p—refinement. The DG method has been widely used in conjunction with explicit time marching for unsteady flows. Implicit RK methods combined with iterative methods for the solution of the large systems of nonlinear equations have been also developed and used for viscous flow calculations. For flows with strong shocks, limiting of high order (DG) expansions is required to stabilize the calculations. In this presentation, a widely used formulation of the DG method, well suited for discretization of complex geometries and p-adaptive calculations, through the implementation of hierarchical expansion functions, is presented. The DG method is applied for calculations of shock dominated unsteady flows encompassing complex flow features. Adaptive mesh refinement (AMR) in flow regions with steep gradients is employed. It is shown that isotropic AMR greatly enhances the resolving ability of lower order expansions. A new approach suitable for limiting high order expansions that also provides sub-cell resolution of discontinuities is presented and applied to compute complex shock interactions. The developed DG framework has been also applied in p-adaptive and h/p adaptive framework to obtain high order accurate numerical solutions. The p-adaptive feature of DG methods can be exploited to revitalize the Hardin and Pope acoustic splitting approach that has been used in the past for airframe noise generated by low speed flows in collocated meshes. The p-refinement feature of the DG method can be exploited for propagating the noise to far field where the mesh for the flow calculations is too coarse to support acoustic propagation. In addition, the limiters developed may be required for regions with steep variations discretized with high order expansions.

Radar cross section Hz component of the magnetic field. Demonstration of a P1–P2–P3 numerical solution of the Maxwell equations. The numerical solution was computed with automatic p-type adaptivity based on cell size and the wavelength of the incident wave.

7.3. Investigation and Inspiration on the Effects of Aerodynamic Interaction Between Propellers and Other Components of UAVs

Name: Xiaolu Wang

Organization: Zhengzhou University of Aeronautics

Lecture Summary/Abstract:

Propeller propulsion systems are widely utilized in modern unmanned aerial vehicles (UAVs), attributed to their high efficiency and versatility. The aerodynamic characteristics and flight performance of these UAVs are shaped by the complex and diverse flow fields produced by the propellers. Initially, we introduce the fundamental principles and parameters of propellers, summarizing the numerical methods used in engineering to evaluate their performance. Subsequently, we classify the UAV propulsion configurations into four categories: traditional propulsion configuration, vertical take-off and landing with hybrid wing configuration, distributed propulsion configuration, and ducted fan configuration. Within each category, we review the research advancements concerning the aerodynamic interactions between propellers and other components of UAVs. Ultimately, an investigative application focusing on the aerodynamic gain design of wings, fuselage, and tail is conducted, with the anticipation of future trends in propeller-driven UAV development. The objective is to provide insights for selecting propeller configurations and facilitating the integrated design of propeller-driven UAVs.

7.4. Harnessing Physics-Informed Neural Networks for Precision and Efficiency in UAVs

Name: Mir Feroskhan

Organization: School of Mechanical and Aerospace Engineering, NTU Singapore, Singapore

Lecture Summary/Abstract:

Physics-Informed Neural Networks (PINNs) can revolutionize UAVs by embedding physical laws directly into neural networks modeling its dynamics, addressing the limitations of traditional mathematical models and data-driven approaches. In this talk, I will explore how PINNs significantly reduce data requirements and improve real-time control by incorporating fundamental aerodynamic equations into the neural network’s learning process. Unlike data-driven models, which demand vast datasets and offer no inherent understanding of the system’s physics, PINNs leverage known physics to accurately model the complex dynamics of multi-rotor drones and other aerial robots. This integration allows for the reduction of data needs by up to 65%, while effectively managing uncertainties in dynamic environments such as sudden wind gusts or visual servoing errors.

Drawing from my research, particularly on visual servoing for multi-rotor control, PINNs have shown the ability to handle up to 70% of system uncertainties and provide real-time control tasks up to 10 times faster than traditional data-driven models. Visual servoing, where a robot’s movement is controlled through camera-based feedback, is especially susceptible to uncertainties in both the robot’s dynamics and the camera system itself. PINNs, by embedding physics into the cost function of neural networks, enable more robust and efficient control solutions for these tasks, making them highly applicable for autonomous flight in unpredictable environments. The talk will further highlight applications of PINNs in other complex aerial tasks, such as modular parcel delivery and eVTOLs. For instance, in collaborative aerial tasks like decentralized parcel delivery, PINNs can efficiently model multi-agent control strategies. Furthermore, the potential of PINNs in modeling unsteady aerodynamics during hover to cruise transition in eVTOLs, will be discussed.

Despite these advantages, challenges remain. Key issues include ensuring the availability of accurate physics laws for unconventional aerial robots and improving the interpretability of the resulting models. Addressing these challenges is essential to fully unlock the potential of PINNs in UAVs, where complex dynamics and uncertainties present significant obstacles. By embedding classical physics into the fabric of neural networks, PINNs offer a promising path forward in the development of more intelligent, adaptable, and efficient UAVs, capable of performing complex tasks in dynamic environments. This talk will provide insights into recent advancements, ongoing research, and future directions, positioning PINNs as a key tool in the future of UAVs.

8. Track 6: Green Airport Technologies and Operation Forum

8.1. International Green Airports Case Studies

Name: Hyvan Tsz Yat Wong

Organization: Mott MacDonald Hong Kong Limited

Lecture Summary/Abstract:

To share experience and cases studies of green airports around the world, focus on various perspectives including green airport strategies and policies, decarbonization, road maps, renewable energy applications and etc.

8.2. Digital-Enabled Green ATM System: History, Advances, Challenges and Future

Name: Zhijun Wu

Organization: Civil Aviation University of China

Lecture Summary/Abstract:

Air Traffic Management (ATM) utilizes aeronautic communication, navigation, surveillance, and automation technologies to dynamically and comprehensively manage air traffic and airspace in a safe, economical, and efficient manner. The development of aeronautic communication, navigation, surveillance, and automation technology has a great impact on the development of green aviation. Taking ADS-B technology as an example, the flight path using ADS-B technology is smoother compared to radar technology and the flight distance is shorter. And, the descent process of an aircraft using ADS-B technology is continuous, while the descent process using radar technology is stepped and requires constant throttle control, resulting in significant fuel consumption. In addition, due to the use of navigation satellite technology, aircraft can fly directly across the ocean, freeing the design of flight routes from the limitations of ground navigation stations, greatly shortening flight distance, reducing flight time, lowering fuel consumption, and greatly improving safety. Hence, with the surge in traffic flow, increasing attention to environmental issues such as carbon emissions, and the emergence of new roles in airspace such as drones, it is urgent to build a sustainable, scalable, and flexible air traffic management system to unify the use of airspace and air traffic management resources of member countries and enhance airspace safety. Therefore, the Digital ATM strategy has emerged to promote the digital transformation and upgrading of air traffic management systems, with a focus on transforming aviation infrastructure through the use of the latest digital technologies to meet the safety and efficiency needs of future air traffic operations, while minimizing the impact of aviation operations on the environment.

The core of digital air traffic control is the network-centric architecture, network- enabled operation, and digital application, involving air traffic control systems, onboard equipment, airline operation control, airport operation command, and other aspects. It is applied in four major scenarios: efficient airport operation, advanced air traffic services, optimized air traffic management networks, and aviation infrastructure upgrades. The challenges faced by digital ATM include the sharing of flight data (including initial flight paths, etc.), network security (including passenger privacy protection and prevention of sensitive information leakage, etc.). It can be foreseen that the implementation of digital ATM strategy can cope with complex and dense airspace, meet the safety and efficiency requirements of future air traffic operations, while minimizing the impact of aviation operations on the environment, thus making a huge contribution to the development of green aviation.

8.3. Hong Kong International Airport–Net Zero Carbon Pledge and Business Partners Carbon Support Programme

Name: Wai Man

Organization: Airport Authority Hong Kong

Lecture Summary/Abstract:

Climate change is the most pressing environmental issue for Hong Kong International Airport (HKIA); meaningful action to mitigate the crisis and prepare for its consequences will be vital to the long-term continuity of our operations. Recognising the goals of the Paris Agreement, Airport Authority Hong Kong (AAHK), the operator of HKIA, aims to curb and limit carbon emissions by working collaboratively with business partners to reduce HKIA’s direct and indirect emissions and become a low-carbon, climate-resilient airport. We have a proud history of leading the airport community to measure, reduce and disclose HKIA’s carbon footprint.

In 2021 we unveiled our HKIA 2050 Net Zero Carbon Pledge: “AAHK and its key aviation-related business partners commit to achieve Net Zero Carbon by 2050, with a midpoint target of 55% absolute emissions reduction by 2035 from a 2018 baseline.”

We currently have buy-in from 30 key aviation-related business partners and launched a dedicated HKIA Business Partners Carbon Support Programme focusing on four main pillars of finance, governance, technology and innovation, and capacity building to drive collaborative action. More details will be provided on HKIA’s Net Zero Carbon Pledge and Business Partners Carbon Support Programme.

8.4. Implementation Paths for Goal- and Effect-Oriented Low-Carbon Buildings

Name: Gang Liu

Organization: School of Architecture, Tianjin University

Lecture Summary/Abstract:

The construction industry, as a fundamental pillar of the national economy, plays a crucial role in carbon emissions. Its high-quality development is essential to advancing national economic and social progress. This report addresses the high energy consumption associated with large public buildings and outlines strategies for diagnosing and selecting key design parameters that affect building performance during the design phase. It further explores the application of intelligent methods to identify energy-saving and emission-reducing implementation pathways. These approaches aim to enhance architects’ capacity to design green, energy-efficient buildings, thereby driving the development of high-quality, low-carbon construction in China.

8.5. Structural Optimization of Chinese Airport Layout Planning Based on Global Green Civil Aviation Governance Perspective

Name: Jie Ouyang

Organization: Civil Aviation University of China

Lecture Summary/Abstract:

Under the background of fundamental changes in the international economic landscape and geopolitical pattern, it is believed that China’s civil aviation is not only a “barometer” of the national economy, but also a “regulator” to promote the transformation and upgrading of the consumption structure. Therefore, the current situation of China’s civil airport layout planning is analyzed, and the idea of optimizing China’s international air route structure under the “the Belt and Road” initiative is proposed. At the same time, from the perspective of global civil aviation governance structure and global aviation emergency rescue needs, the plan for optimizing China’s airport layout structure is proposed, and specific countermeasures such as “forward access” for international flights, “cut corners and straighten” for international routes, and “teaming up” for airport groups are proposed.

9. Track 7: eVTOLs Forum

Ground Effect on the Flow Stability of the Ducted-Fan Propulsion System in Flying Car

Name: Yuping Qian

Organization: Tsinghua University

Lecture Summary/Abstract:

As urban air traffic demand increases, flying cars are rapidly developing, with electric ducted-fans becoming the preferred propulsion system due to their efficiency, safety, and low noise levels. However, during near-ground operations such as vertical takeoff and landing of flying cars, ground effect cause dynamic thrust fluctuations in ducted-fan propulsion system, severely affecting the safety of near-ground flights. In response to this issue, Tsinghua University Turbo e-Power Team has conducted research on the impact of ground effect on the flow stability of ducted-fan. Under near-ground conditions, ground effect would trigger rotating stall in the ducted-fan, and the rotating stall cells are the main cause of dynamic thrust fluctuations. Further investigations into aerodynamic design and flow control methods were conducted to improve the flow stability of ducted-fans and reduce thrust fluctuations. This research will provide theoretical and technical support for enhancing the safety of ducted-fan propulsion system during near-ground flight of flying cars.

10. Track 8: AI in Green Aviation Transformation Forum

On the Autonomous and Synergistic Capabilities of UAVs in BVLOS and High-Risk Environment

Name: Xianchang Wang

Organization: Shenyang Aerospace University

Lecture Summary/Abstract:

With the rapid development of the low-altitude economy in China, the relevant UAV flight regulations in the urban environment will pose much higher requirement for UAV’s autonomy and collaborative capability. These regulations are further requirements for the information integration, autonomy and collaboration capabilities of UAVs in BVLOS and high risk environment. This discussion uses some regulation examples in low-altitude flight in typical scenarios to discuss the basic autonomy and coordination capabilities and the Platform-independent interface description specification for the current and future UAVs.

11. Track 9: Green MRO Forum

Not available.

12. Track10: China-France Seminar on Aero-Power

12.1. Effect of Laser Energy and Scanning Speed on Temperature and Residual Stress of Ni-Based Superalloys

Name: Sabeur Msolli

Organization: The University of Technology of Belfort-Montbéliard (UTBM)

Lecture Summary/Abstract:

Nickel-based superalloys are a class of high-tech materials that are mostly made of nickel with significant amounts of other elements such as cobalt, chromium, iron, aluminium, titanium, and more. These alloys are designed to withstand harsh circumstances, particularly in high-temperature and high-stress situations like those found in gas turbines, jet engines, and aerospace settings. They have the following important characteristics such as elevated temperature strength, resistance to oxidation and corrosion, creep resistance, resistance to fatigue, high thermal stability, and weldability. These materials find extensive use in aerospace, aviation, and power generation industries, meeting the demand for high-performance substances in challenging conditions. Specific applications range from turbine blades and combustion chambers in aircraft engines to components in power plants dedicated to energy generation. The evolution and adoption of nickel-based superalloys have been instrumental in advancing the efficiency and performance of diverse technologies. Nickel-based superalloys are nowadays fabricated using LPBF process offering more flexibility in part shaping and conserving the excellent properties of the material. The alloying elements are critical in providing the final characteristics of the LPBF and special attention should be addressed to such aspect. Among the major characteristics are the crack initiation and propagation and the tensile strength. Residual stresses are pointed out as potential precursors of failure and the residual stress therefore are straightly related to the alloy composition. Besides the experience, numerical simulations of the residual stress are important to decide whether the LPBF part can hold under thermal loadings. Therefore, in the work presented in this report, we present an introduction to the development of a FEM model which will be useful to predict residual stress generated from LPBF process and the associated deformations and temperatures (Figure 1).

12.2. A Method for Identifying the Properties of CMC Material Components Based on Multi-Scale Constitutive Models and Multi-Dimensional Boundary Condition

Name: Sheng Huang

Organization: Northwestern Polytechnical University

Lecture Summary/Abstract:

Ceramic Matrix Composites (CMC) are ideal structural materials for high-temperature components such as turbine blades and combustion chamber casings in aero engines due to their high temperature resistance, high specific stiffness, and high specific strength. When combined with film cooling, they can withstand higher turbine inlet temperatures than high-temperature alloy materials. However, the efficient development of multi-scale models and a comprehensive material property database remain key challenges limiting the engineering application of CMC.

In this study a macro-micro combined finite element model is established, which is capable of representing the densification structure around pores based on CT scan images. A progressive damage model for CMC is developed using the 3D Hashin failure criterion and a modified Von-Mises failure criterion. By analyzing the uniaxial tensile stress-strain behavior of CMC specimens under both room temperature and high-temperature conditions, and utilizing techniques such as CT scans and scanning electron microscopy, the study reveals the influence of parameters such as porosity, pore diameter, and densification band radius on the mechanical properties of CMC.

To address the under-constrained issues and size effects in CMC mechanical testing, an inversion method for the elastic parameters of CMC micro-components is developed based on the aforementioned macro-micro combined model. A novel error function refinement method based on multi-scale and multi-modal experimental data is proposed, effectively improving the inversion accuracy of the target component parameters. The inversion optimization process is significantly accelerated by employing a BP+UNet neural network. Bayesian methods are utilized for uncertainty parameter inference, enriching the inversion results of CMC micro-component elastic parameters, and establishing a parameter identification method that considers dispersion.

The proposed method can predict, identify, and analyze the elastic parameters of CMC micro-components and the macroscopic strength parameters. It allows for the extraction of more comprehensive material parameter information from traditional macroscopic mechanical tests of CMC, further reducing experimental and application costs.

12.3. Fourier-Based Efficient Numerical Methods for Turbomachinery Aeroelasticity Analysis in a Multi-Stage Environment

Name: Dingxi Wang

Organization: Northwestern Polytechnical University

Lecture Summary/Abstract:

Axial-flow turbomachinery is often designed with multiple stages. In a multi-stage environment, the coupling between blade rows is often important for aeroelasticity. To capture blade-row coupling effects for aeroelastic analysis, there is a need to solve the unsteady flow governing equations in a domain consisting of multiple stages. The most straightforward approach to such a mission is the time-domain-time-marching method. This approach also has the highest fidelity. However, this approach is computationally extensive and not amenable to the strict time constraints of routine design activities even with today’s computing resources.

To meet the time constraints, the temporal and spatial periodicity of the unsteady flows within a multi-stage turbomachine has been explored to develop efficient numerical methods. Truncated Fourier series have been used to approximately represent a flow field with strong temporal and spatial periodicity. With this, on one hand, an unsteady analysis can be transformed into a quasi-steady analysis, bypassing the lengthy process required for filtering the influence of initialization. On the other hand, the size of a computational domain can be reduced to one blade passage, achieving further gain in computational efficiency.

The use of truncated Fourier series for an efficient solution of unsteady flows in a multi-stage machine needs to circumvent two more key issues. The first one is how to couple temporal and spatial harmonics in a single solution, which is required to capture every other blade row interaction. The second one is how to couple solutions between adjacent blade rows.

To solve the first issue, a coupled time and passage spectral method has been proposed. The coupled time and passage spectral method uses a coupled time and passage Fourier series to present temporal and spatial periodic flow fields, unifying the representation of temporal harmonics and spatial harmonics. A time-and-space oversampling method together with a modified Gram-Schmidt process is used to perform a coupled non-uniform time and space sampling.

To solve the second issue, a time and space mode decomposition and matching method has been proposed. The method uses a coupled time and space Fourier series to represent flow field at a constant radius of a rotor-stator interface. By matching corresponding flow modes across an interface, the method can faithfully relay solution information across an interface. This method is also generic as it can handle analysis for both blade row interaction and flutter.

Finally, test cases will be presented to demonstrate the effectiveness of the proposed methods in capturing multi-stage coupling effect and the importance of capturing multi-stage coupling effect in an aeroelasticity analysis.

13. Accepted (Extended) Abstracts

13.1. A Dynamic Topology Optimization Method Extending the Service Life of Viscoelastic Materials

• Ziyu Liang ^1,2, Huanhuan Gao ^1,2 and Guikai Guo ^1,2
• ¹ Key Laboratory of CNC Equipment Reliability, Ministry of Education, School of Mechanical and Aero Space Engineering, Jilin University
• ² School of Mechanical and Aerospace Engineering, Jilin University

Abstract: We propose a new structural dynamic topology optimization method based on the Solid Isotropic Material with Penalization (SIMP) model in order to reduce the material fatigue damage by adjusting dissipation energy constraint. In our research scheme, we employ the Finite Element Method to acquire the structural displacement and velocity fields. Then, the adjoint variable method is applied to obtain the sensitivities of the structural dynamic compliance and the disspation energy constraint with respect to the design variables. Finally, the pseudo density design variables are optimized with the Method of Moving Asymptotes (MMA) to yield the minimum of the dynamic compliance. Three numerical examples with different load-cases are carried out to illustrate the validity and the stability of the proposed method, and the obtained structural topology patterns, together with the structural performance functions, are compared with those yielded without the dissipation energy constraint.

Keywords: viscoelastic materials; material fatigue damage; topology optimization; dynamic structural analysis; dissipation energy constraint; adjoint variable method

13.2. Dynamic Topology Optimization for Fail-Safe Structures Using the Adaptive Bubble Method

• Zhenyang Ma, Shouyu Cai, Shun Li and Delu Duan
• School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou

Abstract: To overcome the shortcomings of dynamic topology optimization design results, which are overly sensitive to local damage due to the absence of redundant structures, this work combines the Adaptive Bubble Method (ABM) and the fail-safe design concept to propose a novel dynamics topology optimization design framework.

Compared with traditional topology optimization methods (such as the Density Based Method and the Level Set Method), ABM boasts advantages like fewer design variables and optimization results with smooth, clear boundaries that can be directly imported into CAD systems. Additionally, ABM employs closed B-splines to construct hole features, effectively preventing local mode phenomena caused by weak elements during the optimization process.

Firstly, to extend the application of ABM to dynamics topology optimization design, a more general adaptive hole introduction method is introduced. By calculating the sensitivity ratio between the objective function and the constraint function, and combining this with a set proportion threshold and variable hole influence area, the reasonable hole introduction position is determined. Subsequently, multiple local failure conditions are considered, and structural failure is simulated by removing material from different areas. Furthermore, the structural frequency or dynamic compliance under all damage conditions are assembled by the KS function, which serves as the optimization objective to establish a dynamics structural topology optimization model considering fail-safe.

Finally, the effectiveness of the proposed design method is demonstrated through the classical design problem of a simply supported beam with fixed midpoints at both ends. Compared to the optimization result without considering fail-safe design, the result that incorporates fail-safe design exhibits more complex redundancy. After local damage, the optimized structure retains more load-bearing paths, which is essential for resisting local damage risks. Furthermore, by comparing the fundamental frequency of the structure before and after damage, it is found that the fundamental frequency of the fail-safe optimized structure decreases by 34% in the most critical damage scenario, significantly less than the 64.98% decrease observed in the structure without fail-safe considerations. This greatly reduces the structure’s sensitivity to local damage, enhances the safety of the optimized results, and proves the effectiveness of the proposed optimization model (Figure 2 and Figure 3).

Keywords: Natural Frequency, Topology Optimization, Adaptive Bubble Method, Fail-Safe, Dynamic Compliance

13.3. Topology Optimization of Support Regions to Maximize the Natural Frequencies of Thin-Walled Structures

• Shun Li, Shouyu Cai
• School of Mechanics and Safety Engineering, Zhengzhou University, Zhengzhou

Abstract: The dynamic performance of structures is significantly affected by their support regions. In this research, we focus on enhancing the fundamental frequencies of thin-walled structures through topology optimization of the support regions using the Weighted IsoGeometric Analysis (WIGA) method. Specifically, this work employs IsoGeometric Analysis (IGA) to ensure both an exact representation of smooth geometries and high-order continuity of physical fields related to thin-walled structures. To address the challenge of precisely imposing displacement constraints on the structure beyond its ends with IGA, the WIGA method is further developed by introducing the concept of Weighted Extended B-spline (WEB), which penalizes the NURBS basis functions of IGA to zero at support regions through the weight function. Then, the support regions can be optimized in a straightforward manner by setting the parameters of the weighting function as design variables. In order to improve the dynamic performance of the thin-walled structure by means of support region topology optimization, the fundamental frequency is set as the optimization objective function, and the weighting function in WIGA is defined using NURBS basis functions, whose values can be freely varied. Moreover, the adaptive Gauss quadrature method, which enables Gaussian integration points to be aggregated at boundaries, is adopted to accelerate the optimization iteration process while ensuring the computational accuracy. Numerical examples demonstrate the convenience, practicality and accuracy of our proposed method in tackling support optimization challenges (Figure 4).

Keywords: topology optimization; natural frequency; support region; isogeometric analysis