Submit to Materials Review for Materials Propose a Special Issue

Journal Browser

► Journal Browser

On the Residual Strength and Damage Identification of Damaged Composite Structure

Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Mechanics of Materials".

Deadline for manuscript submissions: closed (20 February 2024) | Viewed by 18107

Share This Special Issue

Special Issue Editors

Dr. Alessandro De Luca

E-Mail Website
Guest Editor

Department of Engineering, University of Campania “Luigi Vanvitelli”, Roma St. 29, 81031 Aversa, Italy
Interests: structural health monitoring; finite element analysis; structural behavior; mechanical design; crashworthiness
Special Issues, Collections and Topics in MDPI journals

Dr. Michele Guida

E-Mail Website
Guest Editor

Department of Industrial Engineering - Aerospace Branch, University of Naples Federico II, Via Claudio, 21 80125 Naples, Italy
Interests: crashworthiness; dynamic impact; biomechanics; structural dynamic; multibody and vehicle dynamics
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Roberto Citarella

E-Mail Website
Guest Editor

Department of Industrial Engineering, University of Salerno, 84084 Fisciano, Italy
Interests: fracture mechanics; fatigue; bioengineering; vibroacoustics; boundary element method; finite element method; statistical energy analysis; dynamics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In recent years, composites have been used in many industrial applications due to their excellent strength, weight, and durability characteristics. Composites come with numerous benefits which encourage engineers to use them in various structural forms. Some examples of these benefits include that they are weight-saving (high specific strength), have low maintenance requirements, exhibit resistance to environmental effects (corrosion-free), are able to be formed into a complex shape, and are easy to install offsite, both as engineered and fabricated elements. However, some negative aspects still limit their use. The most important issues in the structural behavior of all composites are some of their dynamic characteristics due to their lightweight superstructure, failure mechanisms, susceptibility to environmental conditions (e.g., humidity), susceptibility to undetectable defects due to the manufacturing process, and damages caused by accidental loads, which lead the current design practice being based on a damage tolerance approach (i.e., use of larger safety factors, stiffeners and scheduling of several inspection operations during the in-service life).

This Special Issue is dedicated to publishing papers in all fields related to composite materials that address recent advances in the research and development of the materials. Results of theoretical, analytical, numerical or experimental investigation can be presented. Review articles can be also proposed. The key focus is on fiber-reinforced composite materials and particle-reinforced composite materials, addressing not only just the usual topics on structural/mechanical properties, but also more novel areas such as intelligent materials, sensing (e.g., structural health monitoring) applications, extreme environment applications, and sustainability areas, such as recyclability and repair strategies, etc.

The topics of interest include but are not limited to:

Structural behavior and mechanical properties of reinforced composite materials;
Load-carrying capacity of pristine and damaged composite structures;
SHM system applications on composite structures;
Crashworthiness of composite structures;
Dynamic behavior of composite structures;
Failure mechanisms in different types of laminate.

Dr. Alessandro De Luca
Dr. Michele Guida
Prof. Roberto Citarella
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

damage tolerance
SHM systems
composite materials
dynamic loads
failure, crashworthiness, and airworthiness
impact loads

Published Papers (10 papers)

Download All Papers

Research

18 pages, 3173 KiB

Open AccessArticle

A New Method to Predict Damage to Composite Structures Using Convolutional Neural Networks

by Laurent Mezeix, Ainhoa Soldevila Rivas, Antonin Relandeau and Christophe Bouvet

Materials 2023, 16(22), 7213; https://doi.org/10.3390/ma16227213 - 17 Nov 2023

Viewed by 1205

Abstract

To reduce the cost of developing composite aeronautical structures, manufacturers and university researchers are increasingly using “virtual testing” methods. Then, finite element methods (FEMs) are intensively used to calculate mechanical behavior and to predict the damage to fiber-reinforced polymer (FRP) composites under impact loading, which is a crucial design aspect for aeronautical composite structures. But these FEMs require a lot of knowledge and a significant number of IT resources to run. Therefore, artificial intelligence could be an interesting way of sizing composites in terms of impact damage tolerance. In this research, the authors propose a methodology and deep learning-based approach to predict impact damage to composites. The data are both collected from the literature and created using an impact simulation performed using an FEM. The data augmentation method is also proposed to increase the data number from 149 to 2725. Firstly, a CNN model is built and optimized, and secondly, an aggregation of two CNN architectures is proposed. The results show that the use of an aggregation of two CNNs provides better performance than a single CNN. Finally, the aggregated CNN model prediction demonstrates the potential for CNN models to accelerate composite design by showing a 0.15 mm precision for all the length measurements, an average delaminated surface error of 56 mm², and an error rate of 7% for the prediction of the presence of delamination. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Graphical abstract

28 pages, 12738 KiB

Open AccessArticle

Modeling the Crack Interference in X80 Oil and Gas Pipeline Weld

by Wei Cui, Zhongmin Xiao, Qiang Zhang, Jie Yang and Ziming Feng

Materials 2023, 16(9), 3330; https://doi.org/10.3390/ma16093330 - 24 Apr 2023

Cited by 1 | Viewed by 902

Abstract

Based on the numerical simulation method of the virtual crack closure technique (VCCT), an interference model was established to investigate the physical problem of two interacting cracks of different sizes in the welding zone of oil and gas pipelines. The obtained results of the current interference problem were compared with those of single crack case. Various crack configurations, such as different crack spacing and different crack sizes, were analyzed. The characteristic quantity fluid pressure load P during the crack propagation process, the peak value of the von Mises stress distribution field of the crack growth path, as well as the difference ∆Bx between the peak value of the magnetic induction intensity component at the crack and the value of the magnetic induction intensity component at its symmetrical position were calculated. The crack interaction scale factors, including

γ_{P}

γ_{Mises}

, and

γ_{Δ B x}

, were compared and analyzed. The numerical modeling results show that when the unequal-length double cracks interfere with each other, the cracks are more likely to propagate toward each other. The tendency of the double-cracks to propagate toward each other gradually weakens as the distance between the crack tips increases and is finally the same as that of single-crack cases. It was also found that the effect of large-sized cracks on small-sized cracks is greater than that of small-sized ones on large-sized ones. The numerical modeling results could be applied for the prediction and analysis of multicrack damage in oil and gas pipeline welds. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

13 pages, 6542 KiB

Open AccessArticle

Deep Drawing Behavior of Metal-Composite Sandwich Plates

by Shun-Fa Hwang and Yu-Ren Li

Materials 2022, 15(19), 6612; https://doi.org/10.3390/ma15196612 - 23 Sep 2022

Cited by 2 | Viewed by 1368

Abstract

The deep drawing behavior of metal-composite sandwich plates, or fiber-metal laminates, in which aluminum or steel sheets are used as the face layer and composite materials are used as the core layer, is discussed in this work to find the workpieces without fractures and wrinkles. Two types of aluminum, 1050 and 6061, are considered their suitability as face sheets. The preheat effect of aluminum 6061 on formability is also investigated. When steel sheets are used, the effect of blank-holder pressure is included. In addition, to understand the deformation of fabric composite, pure composite laminates are deep drawn. The results of composite laminates show that after drawing, the weft and warp lines are shorter than the other radial lines, causing the specific deformed shape and the variation of the fiber intersection angle. For Al-composite sandwich plates, fractures and wrinkles are easy to occur. Even though the fracture and wrinkle conditions are released with the increase in preheating temperature of aluminum 6061, it may be not enough. For the deep drawing of the steel-composite sandwich plates, in which fractures are avoided, the increase of blank-holder pressure could reduce the wrinkle number. Hence, good quality workpieces without fracture and wrinkle could be obtained when the blank-holder pressure is high enough. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

10 pages, 2439 KiB

Open AccessEditor’s ChoiceArticle

Biocompatibility of Zinc Matrix Biodegradable Composites Reinforced by Graphene Nanosheets

by Mei Fan, Fei Zhao, Shanshan Peng, Qianfei Dai, Yuan Liu, Sheng Yin and Zongkui Zhang

Materials 2022, 15(18), 6481; https://doi.org/10.3390/ma15186481 - 19 Sep 2022

Cited by 6 | Viewed by 1621

Abstract

As a new type of biodegradable implant material, zinc matrix composites have excellent potential in the application of biodegradable implants because of their better corrosion resistance than magnesium matrix materials. Our previous studies have shown that graphene nanosheet reinforced zinc matrix composites (Zn-GNS) prepared by spark plasma sintering (SPS) have good mechanical properties and suitable degradation rate. However, the biocompatibility of zinc matrix composites is still a problem of concern. The cytocompatibility and blood compatibility of pure zinc and Zn-GNS composites in vitro were studied. The results showed that Zn-GNS composites had acceptable toxicity to MG-63 human osteosarcoma cells. In addition, the hemolysis rate of pure zinc and its composites were less than 3%, which has no adverse effect on adhered platelets, and has good antithrombotic and antiadhesion platelets properties. In conclusion, the addition of GNS did not adversely affect the biocompatibility of Zn-GNS composites, which indicated that Zn-GNS composites are a promising candidate for bone implantation. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

15 pages, 11247 KiB

Open AccessArticle

A Study on the Ultrasonic Regulation of the Welding Performance and Residual Stress of 316L Stainless Steel Pipes

by Xiaowei Jiang, Chunguang Xu, Jingdong Li, Jiangquan Lu and Lin Wang

Materials 2022, 15(18), 6255; https://doi.org/10.3390/ma15186255 - 08 Sep 2022

Cited by 2 | Viewed by 1430

Abstract

Due to its extreme service conditions, low-temperature pressure piping often needs post-welding stress measurement and control. Aiming at the phenomenon of local stress concentration in welded 316L pipes, this study used ultrasound to regulate the stress in the welded area at different times during and after the multi-layer welding of the pipeline butt joint for different time lengths. Mechanical properties such as tensile strength and hardness were tested for each comparison group, and the microcrystalline phases of the weld and its surrounding microstructure were analyzed. The transverse and longitudinal surface residual stresses of each comparison group were measured. The influence of high-energy ultrasound on the surface temperature field during and after welding was analyzed. The experimental results show that ultrasonic wave regulation can speed up heat exchange and radiation in the weld zone (WZ), refine the grains in the WZ, heat-affected zone (HAZ) and fusion zone (FZ) to some extent and reduce and homogenize residual stress to a certain degree. In the 120 mm area of the weld center, the residual stress measured after the mid-welding regulation was smaller than that of any other comparison group. This regulation result was the best, followed by that of hot regulation and finally that of offline regulation. The tensile strengths obtained by the mid-welding regulation and post-welding hot regulation of this group were the best, increasing by 17.2% and 24.3%, respectively, compared with the untreated groups. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

16 pages, 2991 KiB

Open AccessArticle

Dynamic Stiffness Matrix Approach to Free Vibration Analysis of Functionally Graded Rotor Bearing System Subjected to Thermal Gradients

by Bharath Obalareddy, Prabhakar Sathujoda and Roberto Citarella

Materials 2022, 15(4), 1540; https://doi.org/10.3390/ma15041540 - 18 Feb 2022

Cited by 3 | Viewed by 1784

Abstract

The dynamic stiffness matrix (DSM) method, an analytical method that provides exact solutions, has been used for the first time for the free vibration analysis of a functionally graded (FG) rotor bearing system subjected to temperature gradients and to investigate its application to FG rotors. The material gradation occurs based on the power law between the inner metal core and the outer ceramic rich layer of the FG rotor. The temperature gradation follows the Fourier law of heat conduction which leads to non-linear temperature distribution (NLTD) in the radial direction of the FG rotor. The development of the DSM formulations for Timoshenko FG rotor elements using the governing equations derived from translational and rotational equilibrium conditions is the novelty of the present work. The DSM of the FG rotor elements, rigid disk and linear isotropic bearings are assembled to obtain the global dynamic stiffness matrix of the FG rotor bearing system. The natural whirl frequencies are computed from the global DSM using the Wittrick–William algorithm as a root searching technique. The natural and whirl frequencies are validated with the results available in the literature and the exactness of the DSM method has been exemplified. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

20 pages, 6900 KiB

Open AccessArticle

Numerical Investigation on Guided Waves Dispersion and Scattering Phenomena in Stiffened Panels

by Alessandro De Luca, Donato Perfetto, Giuseppe Lamanna, Antonio Aversano and Francesco Caputo

Materials 2022, 15(1), 74; https://doi.org/10.3390/ma15010074 - 23 Dec 2021

Cited by 23 | Viewed by 2579

Abstract

The aim of this work is to propose a numerical methodology based on the finite element (FE) method to investigate the dispersive behavior of guided waves transmitted, converted, and reflected by reinforced aluminum and composite structures, highlighting their differences. The dispersion curves of such modes can help designers in improving the damage detection sensitivity of Lamb wave based structural health monitoring (SHM) systems. A preliminary phase has been carried out to assess the reliability of the modelling technique. The accuracy of the results has been demonstrated for aluminum and composite flat panels by comparing them against experimental tests and semi-analytical data, respectively. Since the good agreement, the FE method has been used to analyze the phenomena of dispersion, scattering, and mode conversion in aluminum and composite panels characterized by a structural discontinuity, as a stiffener. The research activity allowed emphasizing modes conversion at the stiffener, offering new observations with respect to state of the art. Converted modes propagate with a slightly slower speed than the incident ones. Reflected waves, instead, have been found to travel with the same velocity of the incident ones. Moreover, waves reflected in the composite stiffened plate appeared different from those that occurred in the aluminum one for the aspects herein discussed. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

16 pages, 7172 KiB

Open AccessArticle

Face Damage Growth of Sandwich Composites under Compressive Loading: Experiments, Analytical and Finite Element Modeling

by Moustafa Kinawy, Felice Rubino, Giacomo Canale, Roberto Citarella and Richard Butler

Materials 2021, 14(19), 5553; https://doi.org/10.3390/ma14195553 - 24 Sep 2021

Cited by 1 | Viewed by 1528

Abstract

Sandwich panels with composite laminate skins having [(±45_C)₂,(0_C,0_G)₄,(±45_C)₂] stacking sequence (subscript C for carbon fibers, G for glass) and containing barely visible impact damage (BVID) induced on the whole sandwich structure impacted at low energy, were tested in edge after-impact-compression with load direction parallel and transversal to the fibers direction (0-dir.). The morphology of impact damage on the sandwich structure was determined by using ultrasonic C-Scan and visual observation of laminate cross section. A Digital Image Correlation (DIC) system was used to measure the delamination evolution during the test. Two different failure behaviors were observed in two different impacted panels. Panel with fibers oriented transversally to the compressive load showed an opening (Mode-I) propagation of a delamination, while the panel with fibers parallel to the load showed shear (Mode-II) propagation. The static load such to determine local buckling of the composite face and failure was experimentally measured. An analytical model was implemented to predict the static strength of laminate with Mode-I opening. An FE model was instead built to predict the local buckling failure mode of the laminate with BVID, which is the first phenomenon to appear. The results of the analytical model and the numerical simulation correlate well with the test. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

13 pages, 3120 KiB

Open AccessArticle

Characterization of Adhesives Bonding in Aircraft Structures

by Maria Grazia Romano, Michele Guida, Francesco Marulo, Michela Giugliano Auricchio and Salvatore Russo

Materials 2020, 13(21), 4816; https://doi.org/10.3390/ma13214816 - 28 Oct 2020

Cited by 11 | Viewed by 2214

Abstract

Structural adhesives play an important role in aerospace manufacturing, since they provide fewer points of stress concentration compared to faster joints. The importance of adhesives in aerospace is increasing significantly because composites are being adopted to reduce weight and manufacturing costs. Furthermore, adhesive joints are also studied to determine the crashworthiness of airframe structure, where the main task for the adhesive is not to dissipate the impact energy, but to keep joint integrity so that the impact energy can be consumed by plastic work. Starting from an extensive campaign of experimental tests, a finite element model and a methodology are implemented to develop an accurate adhesive model in a single lap shear configuration. A single lap joint finite element model is built by MSC Apex, defining two specimens of composite material connected to each other by means of an adhesive; by the Digimat multi-scale modeling solution, the composite material is treated; and finally, by MSC’s Marc, the adhesive material is characterized as a cohesive applying the Cohesive Zone Modeling theory. The objective was to determine an appropriate methodology to predict interlaminar crack growth in composite laminates, defining the mixed mode traction separation law variability in function of the cohesive energy (G_c), the ratio between the shear strength τ and the tensile strength σ (

β_{1}

), and the critical opening displacement υ_c. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

20 pages, 2798 KiB

Open AccessArticle

Effect of Corrosion on the Natural and Whirl Frequencies of a Functionally Graded Rotor-Bearing System Subjected to Thermal Gradients

by Prabhakar Sathujoda, Bharath Obalareddy, Aneesh Batchu, Giacomo Canale, Angelo Maligno and Roberto Citarella

Materials 2020, 13(20), 4546; https://doi.org/10.3390/ma13204546 - 13 Oct 2020

Cited by 8 | Viewed by 1839

Abstract

Corrosion causes a loss of material resulting in the reduction of mass and stiffness of a component, which consequently affects the dynamic characteristics of any system. Fundamental frequency analysis of a corroded functionally graded (FG) rotor system, using the finite element method based on the Timoshenko beam theory, was investigated in the present paper. The functionally graded shaft consisting of an inner metallic core and an outer ceramic layer was considered with the radial gradation of material properties based on the power law. Nonlinear temperature distribution (NLTD) based on the Fourier law of heat conduction was used to simulate the thermal gradient through the cross-section of the FG rotor. The finite element formulation for a functionally graded shaft with a corrosion defect was developed and the dynamic characteristics were investigated, which is the novelty of the present work. The corrosion parameters such as length, depth and position of the corrosion defect in the shaft were varied and a parametric study was performed to investigate changes in the natural and whirl frequencies. An analysis was carried out for different power indexes and temperature gradients of the functionally graded shaft. The effects of corrosion were analysed and important conclusions are drawn from the investigations. Full article

(This article belongs to the Special Issue On the Residual Strength and Damage Identification of Damaged Composite Structure)

► Show Figures

Figure 1

Journal Menu

Journal Browser

On the Residual Strength and Damage Identification of Damaged Composite Structure

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (10 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI