Search Results (32)

Crash boxes play a crucial role in automotive safety by absorbing impact energy during collisions. The advancement of additive manufacturing (AM), particularly Fused Deposition Modeling (FDM), has enabled the fabrication of geometrically complex and lightweight crash boxes. This study presents a comparative evaluation of the crashworthiness performance of five FDM materials, namely, PLA+, PLA-ST, PLA-LW, PLA-CF, and PETG, across four structural configurations: Single-Cell Circle (SCC), Multi-Cell Circle (MCC), Single-Cell Square (SCS), and Multi-Cell Square (MCS). Quasi-static axial compression tests are conducted to assess the specific energy absorption $\left(SEA\right)$ and crush force efficiency $\left(CFE\right)$ of each material–geometry combination. Among the materials, PLA-CF demonstrates superior performance, with the MCC configuration achieving an $SEA$ of 22.378 ± 0.570 J/g and a $CFE$ of 0.732 ± 0.016. Multi-cell configurations consistently outperformed single-cell designs across all materials. To statistically quantify the influence of material and geometry on crash performance, a two-factor ANOVA was performed, highlighting geometry as the most significant factor across all evaluated metrics. Additionally, a comparative test with aluminum 6063-T5 demonstrates that PLA-CF offers comparable crashworthiness, with advantages in mass reduction, reduced $PCF$, and enhanced design flexibility inherent in AM. These findings provide valuable guidance for material selection and structural optimization in FDM-based crash boxes. Full article

Crash boxes play a vital role in improving vehicle safety by absorbing collision energy and reducing the forces transmitted to occupants. Additive manufacturing (AM) has become a powerful method for developing advanced crash boxes by enabling complex geometries. This review provides a comprehensive examination of recent progress in AM crash boxes, with a focus on three key aspects: geometric design innovations, material behavior, and manufacturing techniques. The review investigates the influence of various AM-enabled structural configurations, including tubular, origami-inspired, lattice, and bio-inspired designs, on crashworthiness performance. Among these, bio-inspired structures exhibit superior energy absorption characteristics, achieving a mean specific energy absorption $\left(SEA\right)$ of 21.51 J/g. Material selection is also explored, covering polymers, fiber-reinforced polymers, metals, and multi-material structures. Metallic AM crash boxes demonstrate the highest energy absorption capacity, with a mean $SEA$ of 28.65 J/g. In addition, the performance of different AM technologies is evaluated, including Stereolithography (SLA), Material Jetting (MJT), Selective Laser Melting (SLM), Selective Laser Sintering (SLS), Fused Deposition Modeling (FDM), and hybrid manufacturing techniques. Among these, crash boxes produced by SLM show the most favorable energy absorption performance, with a mean $SEA$ of 16.50 J/g. The findings presented in this review offer critical insights to guide future research and development in the design and manufacturing of next-generation AM crash boxes intended to enhance vehicle safety. Full article

Crash boxes play a crucial role in mitigating force during vehicle collisions by absorbing impact energy. Additive manufacturing (AM), particularly Fused Deposition Modeling (FDM), has emerged as a promising method for their fabrication due to its design flexibility and continuous advancements in material development. This study investigates the crash performance of tapered crash box configurations, each manufactured using two FDM materials: Carbon Fiber-Reinforced Polylactic Acid (PLA-CF) and Polylactic Acid Plus (PLA+). The specimens vary in wall thickness and taper angles to evaluate the influence of geometric and material parameters on crashworthiness. The results demonstrated that both specific energy absorption ($SEA$) and crush force efficiency ($CFE$) increase with wall thickness and taper angle, with PLA-CF consistently outperforming PLA+ in both metrics. ANOVA results showed that wall thickness is the most influential factor in crashworthiness, accounting for 73.18% of $SEA$ variation and 58.19% of $CFE$ variation. Taper angle contributed 13.49% to $SEA$ and 31.49% to $CFE$, while material type had smaller but significant effects, contributing 0.66% to $SEA$ and 0.11% to $CFE$. Regression models were developed based on the experimental data to predict $SEA$ and $CFE,$ with a maximum absolute percentage error of 4.97%. These models guided the design of new configurations, with the optimal case achieving an $SEA$ of 32.086 ± 0.190 kJ/kg and a $CFE$ of 0.745 ± 0.034. The findings confirm the potential of PLA-CF in enhancing the energy-absorption capability of crash boxes, particularly in tapered designs. Full article

Magnetic pulse welding (MPW) is a promising solid-state joining process that utilizes electromagnetic forces to create high-speed, impact-like collisions between two metal components. This welding technique is widely known for its ability to join dissimilar metals, including aluminum, steel, and copper, without the need for additional filler materials or fluxes. MPW offers several advantages, such as minimal heat input, no distortion or warping, and excellent joint strength and integrity. The process is highly efficient, with welding times typically ranging from microseconds to milliseconds, making it suitable for high-volume production applications in sectors including automotive, aerospace, electronics, and various other industries where strong and reliable joints are required. It provides a cost-effective solution for joining lightweight materials, reducing weight and improving fuel efficiency in transportation systems. This contribution concerns an application for the automotive sector (body-in-white) and specifically examines the welding of AA6082-T6 aluminum alloy with HC420LA cold-rolled micro-alloyed steel. One of the main aspects for MPW optimization is the determination of the process window that does not depend on the equipment used but rather on the parameters associated with the physical mechanisms of the process. It was demonstrated that process windows based on contact angle versus output voltage diagrams can be of interest for production use for a given component (shock absorbers, suspension struts, chassis components, instrument panel beams, next-generation crash boxes, etc.). The process window based on impact pressures versus impact velocity for different impact angles, in addition to not depending on the equipment, allows highlighting other factors such as the pressure welding threshold for different temperatures in the impact zone, critical transition speeds for straight or wavy interface formation, and the jetting/no jetting effect transition. Experimental results demonstrated that optimal welding conditions are achieved with impact velocities between 900 and 1200 m/s, impact pressures of 3000–4000 MPa, and impact angles ranging from 18–35°. These conditions correspond to optimal technological parameters including gaps of 1.5–2 mm and output voltages between 7.5 and 8.5 kV. Successful welds require mean energy values above 20 kJ and weld specific energy values exceeding 150 kJ/m². The study establishes critical failure thresholds: welds consistently failed when gap distances exceeded 3 mm, output voltage dropped below 5.5 kV, or impact pressures fell below 2000 MPa. To determine these impact parameters, relationships based on Buckingham’s π theorem provide a viable solution closely aligned with experimental reality. Additionally, shear tests were conducted to determine weld cohesion, enabling the integration of mechanical resistance isovalues into the process window. The findings reveal an inverse relationship between impact angle and weld specific energy, with higher impact velocities producing thicker intermetallic compounds (IMCs), emphasizing the need for careful parameter optimization to balance weld strength and IMC formation. Full article

Impact absorbers are needed in many different areas in terms of energy absorption and crashworthiness. While the design of these structures is expected to increase mechanical performance, they are expected to be lightweight, and when evaluated in this context, lattice structures come to the fore. In this study, impact absorbers, also known as crash boxes, consisting of lattice structures designed to increase energy absorption performance were fabricated by a new manufacturing method, metal powder additive manufacturing, and their mechanical performance was experimentally investigated under quasi-static axial loading, and energy absorption data were obtained. The specimens were designed from Ti6Al4V, INC 718, and AISI 316L materials by forming 18 matrix structures with square and hexagonal geometries. According to this study, the lattice structures absorbed up to 4.5 times more energy than the shell structures of a similar material group. According to the normalized values among all samples, the hexagonal sample made of Ti6Al4V material showed 4.3 times higher energy absorption efficiency. The AISI 316L material showed the best crushing performance due to its ductile structure. Full article

Lightweighting is a critical focus in the transportation sector, directly enhancing efficiency and significantly reducing costs. In electric vehicle (EV) design, the body surrounding the battery must effectively absorb impact, especially during crashes. This study aims to improve the crash performance of the side profiles in the battery box of an M1 category vehicle. It is based on the crash test in Annex 8D of the ECE R100 regulation. In this study, the safe displacement at which the battery will not deform is set as 20 mm, and the maximum force and energy absorption at this displacement are compared. In total, 33 different electric and hybrid vehicle models were benchmarked in this study. L-shaped geometry and aluminum materials are generally preferred; this study focuses on using glass-fiber-reinforced polymer (GFRP) pultruded profiles to make batteries more durable and lighter. The GF800 material was selected for its superior mechanical strength among glass fiber composites. A virtual tensile test verified its properties. A unique hybrid model combining honeycomb and auxetic geometries was developed, showing a crash performance improvement of ~360% over honeycomb structures and ~88% over auxetic structures. Through multi-objective optimization using artificial neural networks (ANNs), 27 models were analyzed, leading to an optimized design. The final design resulted in the battery box side profile being 23.9% lighter and 38.6% cheaper, and exhibiting a performance 3% higher. This study demonstrates significant advancements in EV safety and cost efficiency, highlighting the practical benefits of innovative material and design approaches. Full article

This study investigated the performance optimization of nickel-cobalt (Ni-Co)-coated absorber panels in solar flat plate collectors (SFPCs) using response surface methodology for sustainable operation and optimized performance. Ni-Co coatings, applied through an electroplating process, represent a novel approach by offering superior thermal conductivity, durability, and environmental benefits compared to conventional black chrome coatings, addressing critical concerns related to ecological impact and long-term reliability. Experiments were conducted to evaluate the thermal efficiency of Ni-Co-coated panels with and without reflectors under varying flow rates, collector angles, and reflector angles. The thermal efficiency was calculated based on the inlet and outlet water temperatures, solar radiation intensity, and panel area. The results showed that the SFPC achieved average efficiencies of 50.9% without reflectors and 59.0% with reflectors, demonstrating the effectiveness of the coatings in enhancing solar energy absorption and heat transfer. A validated quadratic regression model (R² = 0.9941) predicted efficiency based on the process variables, revealing significant individual and interaction effects. Optimization using the Box–Behnken design identified the optimal parameter settings for maximum efficiency: a flow rate of 1.32 L/min, collector angle of 46.91°, and reflector angle of 42.34°, yielding a predicted efficiency of 79.2%. These findings highlight the potential of Ni-Co coatings and reflectors for enhancing SFPC performance and provide valuable insights into the sustainable operation of solar thermal systems. Furthermore, the introduction of Ni-Co coatings offers a sustainable alternative to black chrome, reducing environmental risks while enhancing efficiency, thereby contributing to the advancement of renewable energy technologies. Full article

To develop a new type of biomimetic single-cell and multi-cell energy-absorbing box (tube) featuring conical tubes at the intersection of cell walls, it is necessary to address the issue of large bottom-space requirements in current conical energy-absorbing tubes with superior crashworthiness due to their large semi-apical angles. This study proposes adding corrugations to conical tubes with small semi-apical angles and modifying the bottom by replacing the last one or two inclined corrugations with vertical ones. Finite element simulation results show that, compared to conventional conical tubes, adding corrugations reduces the optimal semi-apical angle of conical tubes by 5°, with the optimal range being 5–10°. Furthermore, the modification method of replacing inclined corrugations with vertical ones effectively mitigates the challenges of increasing peak crushing force and large end-peak crushing force as the semi-apical angle increases. This structural optimization lays a foundation for the development of new biomimetic single-cell and multi-cell energy-absorbing boxes (tubes) incorporating conical tubes. Full article

The conventional Trombe wall (TW) with concrete construction has been shown to enhance the indoor environment of buildings in cold and Mediterranean climates. Thus, a TW is an option for reducing energy consumption related to thermal comfort for buildings in the northwestern region of Mexico, characterized by arid and semi-arid conditions with low winter temperatures. The thermal behavior of the TW and a conventional facade (CF) of concrete were compared when installed in the southern wall of reduced-scale test boxes in Ensenada, B.C. Unlike other research works available in the literature, which typically monitored a data point measure of the wall and room temperatures, the present study measured the temperature of key components: the absorber wall, the air at the bottom and top vents, the glass cover, and the air at the cross-section plane of the TW test box. The results showed that the TW increases the air temperature through its channel up to ${14}^{ \circ }$C and yields a maximum thermal efficiency of 84% during a sunny winter week. Further, the indoor air temperature at the midpoint of the TW test module is up to $6^{ \circ }$C greater than the obtained on the CF-test module; therefore, the TW improved the thermal comfort conditions during winter. Full article

Road accidents cause considerable losses to road users and to society. The steady increase in the number of vehicles leads to increased traffic volume. Therefore, there is a real need to improve passenger safety by developing passive safety systems. This article presents the results of experimental tests of structures absorbing kinetic energy, which could be used in the front section of a vehicle in order to reduce the consequences of passenger car head-on collisions. A number of crash tests of selected structures were conducted under various load conditions. An analysis was carried out of parameters enabling the authors to assess the level of energy absorption by the absorbers made, and compare these to absorbers available on the market. The tests carried out made it possible to determine energy absorption capability of the crash boxes prepared and to identify a structure exhibiting the most advantageous properties from the point of view of its prospective use. Of all of the absorbers analysed, in the context of energy absorption, it was the absorber made of glass-fibre-reinforced polyphenylene sulphide that produced the most advantageous results. Nonetheless, favourable results were obtained for all of the structures tested. Full article

Origami-shaped composite structures are currently being explored for their ability to absorb energy in a progressive and controlled manner. In vehicle passive safety applications, this prevents the occurrence of peak forces that could potentially cause injuries to vehicle passengers. The work presents the design of a carbon fiber-reinforced polymer (CFRP) crash box for a Formula Student race car, using a numerical model validated by experimental tests. An initial characterization of the material is conducted according to the standards. Following, six origami samples are manufactured and subjected to crash tests to gather accurate experimental data. The numerical model is validated on the tests and used for the design of the race car’s impact attenuator. The designed crash box meets the Formula Student requirements while reducing the total mass by 14% and the maximum deceleration of 21% compared with the previous design. The study confirms the potential use of origami structures to improve crashworthiness while reducing vehicle weight. Full article

Creating lightweight and impact-resistant box structures has been an enduring pursuit among researchers. A new energy-absorbing structure consisting of a bionic gradient lattice-enhanced thin-walled tube is presented in this article. The gradient lattice and thin-walled tube were prepared using selective laser melting (SLM) and wire-cutting techniques, respectively. To analyze the effects of gradient pattern, mass ratio, diameter range and impact speed on structural crashworthiness, low-speed impact at 4 m/s and finite element simulation experiments were conducted. The study demonstrates that the design of inward radial gradient lattice-reinforced thin-walled tubes can effectively enhance structure’s energy-absorption efficiency and provide a more stable mode of deformation. It also shows a 17.44% specific energy-absorption advantage over the uniformly lattice-reinforced thin-walled tubes, with no significant overall gain in peak crushing force. A complex scale evaluation method was used to determine the optimum structure and the structure type with the best crashworthiness was found to be a gradient lattice-filled tube with a thickness of 0.9 mm and a slope index of 10. The gradient lattice-reinforced thin-walled tube suggested in this investigation offers guidance for designing a more efficient thin-walled energy-absorption structure. Full article

In order to meet the higher requirements of energy-absorbing structures in the lightweight automobile design, the mechanical design and impact energy absorption of porous TPMS structures are studied. Eight kinds of porous TPMS structure elements, Gyroid, Diamond, I-WP, Neovius, Primitive, Fischer-Koch S, F-RD, and PMY, are designed based on Matlab, and the porous structure samples composed of eight elements are printed and molded using SLM. The deformation mechanism, mechanical response, and energy absorption characteristics of different porous TPMS structures are investigated. Gyroid and Primitive elements are selected to fill the internal structure of the energy-absorbing automobile boxes. Traditional thin-walled energy-absorbing boxes served as a control group and were subjected to low-speed impact testing. The results show that the peak load of the energy-absorbing box filled with TPMS porous structures is almost equal to the average load under a 4.4 m/s impact, and the SEA of the energy-absorbing box filled with TPMS porous structures is higher than the traditional thin-walled energy-absorbing box. The problems of excessive peak load and inconsistent load fluctuation of traditional thin-walled energy-absorbing structures are effectively solved by porous TPMS structures with the assurance that the lightweight and energy-absorbing requirements are still met. Full article

Bio-inspired gyroid triply periodic minimum surface (TPMS) lattice structures have been the focus of research in automotive engineering because they can absorb a lot of energy and have wider plateau ranges. The main challenge is determining the optimal energy absorption capacity and accurately capturing plastic plateau areas using finite element analysis (FEA). Using nTop’s Boolean subtraction method, this study combined walled TPMS gyroid structures with a normal TPMS gyroid lattice. This made a composite TPMS gyroid lattice (CTG) with relative densities ranging from 14% to 54%. Using ideaMaker 4.2.3 (3DRaise Pro 2) software and the fused deposition modeling (FDM) Raise3D Pro 2 3D printer to print polylactic acid (PLA) bioplastics in 1.75 mm filament made it possible to slice computer-aided design (CAD) models and fabricate 36 lattice samples precisely using a layer-by-layer technique. Shimadzu 100 kN testing equipment was utilized for the mechanical compression experiments. The finite element approach validates the results of mechanical compression testing. Further, a composite CTG was examined using a field emission scanning electron microscope (FE-SEM) before and after compression testing. The composite TPMS gyroid lattice showed potential as shock absorbers for vehicles with relative densities of 33%, 38%, and 54%. The Gibson–Ashby model showed that the composite TPMS gyroid lattice deformed mainly by bending, and the size effect was seen when the relative densities were less than 15%. The lattice’s relative density had a significant impact on its ability to absorb energy. The research also explored the use of these innovative foam-like composite TPMS gyroid lattices in high-speed crash box scenarios to potentially enhance vehicle safety and performance. The structures have tremendous potential to improve vehicle safety by acting as advanced shock absorbers, which are particularly effective at higher relative densities. Full article

Polymer foams are extensively utilized because of their superior mechanical and energy-absorbing capabilities; however, foam materials of consistent geometry are difficult to produce because of their random microstructure and stochastic nature. Alternatively, lattice structures provide greater design freedom to achieve desired material properties by replicating mesoscale unit cells. Such complex lattice structures can only be manufactured effectively by additive manufacturing or 3D printing. The mechanical properties of lattice parts are greatly influenced by the lattice parameters that define the lattice geometries. To study the effect of lattice parameters on the mechanical stiffness of lattice parts, 360 lattice parts were designed by varying five lattice parameters, namely, lattice type, cell length along the X, Y, and Z axes, and cell wall thickness. Computational analyses were performed by applying the same loading condition on these lattice parts and recording corresponding strain deformations. To effectively capture the correlation between these lattice parameters and parts’ stiffness, five machine learning (ML) algorithms were compared. These are Linear Regression (LR), Polynomial Regression (PR), Decision Tree (DT), Random Forest (RF), and Artificial Neural Network (ANN). Using evaluation metrics such as mean squared error (MSE), root mean squared error (RMSE), and mean absolute error (MAE), all ML algorithms exhibited significantly low prediction errors during the training and testing phases; however, the Taylor diagram demonstrated that ANN surpassed other algorithms, with a correlation coefficient of 0.93. That finding was further supported by the relative error box plot and by comparing actual vs. predicted values plots. This study revealed the accurate prediction of the mechanical stiffness of lattice parts for the desired set of lattice parameters. Full article