{"title":"Feasibility study on additive-manufactured honeycomb sandwich structural solutions for a Fast Patrol Vessel","authors":"Simone Scattareggia Marchese , Gabriella Epasto , Vincenzo Crupi , Yordan Garbatov","doi":"10.1016/j.compstruct.2024.118607","DOIUrl":"10.1016/j.compstruct.2024.118607","url":null,"abstract":"<div><div>This work represents a significant step toward integrating additive-manufactured honeycomb sandwiches into ship hull structures. The sandwich structure consists of two continuous fibre-reinforced thermoplastic faces and a regular honeycomb core made of chopped fibre-reinforced thermoplastic. The primary goal is to create optimal manufacturing and design methods to determine to which extent the sandwich solution that has been analysed may be used as a structural component of a fast patrol vessel. The core of the design procedure is a purposely developed evolutionary multiobjective optimisation routine suited to evaluate the flexural response of the structure under investigation. The analytical formulations utilised to predict the structural response of an additive-manufactured honeycomb sandwich subjected to 3-point bending have been derived using a combined analytical and experimental approach. A fast patrol vessel made of steel has been taken as a reference to demonstrate the capabilities of the proposed solution. A steel primary stiffener and its associated plate have been extracted from the midship section and replaced by an additively manufactured honeycomb sandwich. By maintaining the same structural encumbrances, it has been found that a pseudo-optimal combination of the mechanical properties of the sandwich base materials can accomplish an exceptional weight reduction of three times.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118607"},"PeriodicalIF":6.3,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mechanical properties and failure analysis of ring-stiffened composite hulls under hydrostatic pressure","authors":"Kaifeng Yuan , Zhenmeng Xia , Lianbo Wang , Linzhi Wu","doi":"10.1016/j.compstruct.2024.118609","DOIUrl":"10.1016/j.compstruct.2024.118609","url":null,"abstract":"<div><div>Ring stiffeners improve the buckling resistance of thin-walled hulls. In this study, theoretical models of buckling and strength failure of ring-stiffened composite hulls (RSCHs) were used to determine the design parameters. The hulls were prepared by filament winding on a mould composed of multi-petal-combined foams and steel shafts. The experimental results showed that the hydrostatic bearing performance of RSCHs was 1.79 times that of an unstiffened composite hull (USCH) with the same weight-to-displacement ratio (<em>WDR</em>). The crack in the damaged stiffened hulls penetrated the entire axis and expanded circumferentially, resulting in a stiffener fracture. Imperfections related to thickness deviations were introduced into a nonlinear buckling model by considering progressive damage. In contrast to the failure mechanism of USCH, the failure pressure of RSCHs was not at the peak of nonlinear buckling, and fibre compressive failure at 90° on the outermost layer of the skin was dominant. The error between simulated and experimental results was 4.64 %. The parameter analysis indicated that the stiffener height and width had different effects on the buckling load. However, when only the same type of strength failure occurred, both were independent of the load. This study demonstrated the load-bearing advantages of RSCHs for ocean engineering applications.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118609"},"PeriodicalIF":6.3,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High-performance composite electrode based on polyaniline/graphene oxide carbon network for vanadium redox flow batteries","authors":"Amanpreet Kaur , Gurpreet Singh , Jun Woo Lim","doi":"10.1016/j.compstruct.2024.118606","DOIUrl":"10.1016/j.compstruct.2024.118606","url":null,"abstract":"<div><div>In this study, an electrode wrapped in a carbon network is fabricated using a straightforward hydrothermal technique. Conducting polymers such as polyaniline (PANi) have been used to form carbon networks on the surfaces of carbon fibers. However, the cycling instability of PANi, which is a consequence of structural modifications, is a significant obstacle to its commercial application. This study presents an innovative and effective approach for synthesizing carbon networks using PANi/reduced graphene oxide (PANi-rGO-CF) composites to enhance the performance of vanadium redox flow battery (VRFB) electrodes. PANi-rGO was deposited on carbon felt using a hydrothermal method, followed by calcination under an argon atmosphere. The presence of graphene oxide facilitated the uniform distribution of PANi and enhanced its stability. PANi-rGO-CF demonstrated superior electrocatalysis toward vanadium redox couples owing to the abundant heteroatom active sites, affording VRFBs with extraordinary stability and outstanding energy efficiency after 100 cycles at 100 mA/cm<sup>2</sup>.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118606"},"PeriodicalIF":6.3,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Research on the influence of impact damage on force identification for composite material","authors":"Yuqing Qiu, Hongli Ji, Chongcong Tao, Jinhao Qiu","doi":"10.1016/j.compstruct.2024.118595","DOIUrl":"10.1016/j.compstruct.2024.118595","url":null,"abstract":"<div><div>The invisible damage caused by low-velocity impacts are safety threats to engineering structures. Thus, impact force identification is crucial in the context of composite structures for both structure health monitoring (SHM) and composite structure design. This paper investigates the process of identifying impacts on composite structures subjected to low-velocity impact. Considering the damage evolution in the composite structure during impact, this paper explores the influence of impact damage on the accuracy of force identification. Impact experiments on carbon fiber reinforced polymer (CFRP) laminates were conducted to obtain impact force peaks and displacement responses. Furthermore, a validated finite element model (FEM) is established for more elaborate analysis on the mechanism. The findings reveal that the structural damage can lead to significant deviations in force identification if the damage is not considered. Finally, a neural network is employed to predict the force history taking impact damage into consideration. This research provides a reference for the composite structures design and health monitoring of engineering structures considering impact damage.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118595"},"PeriodicalIF":6.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Smolnicki Michał, Duda Szymon, Zielonka Paweł, Stabla Paweł
{"title":"Damage characterisation of GFRP composites based on clustering acoustic emission events utilizing single-failure-cause tests as reference","authors":"Smolnicki Michał, Duda Szymon, Zielonka Paweł, Stabla Paweł","doi":"10.1016/j.compstruct.2024.118596","DOIUrl":"10.1016/j.compstruct.2024.118596","url":null,"abstract":"<div><div>A new method to identify causes of fracture in composites based on acoustic emission (AE) and clusterization of AE data based on reference datasets is presented within the manuscript. Acoustic Emission (AE) is a widely used non-destructive method for fracture analysis, but data due to their multidimensionality are not easy to analyze especially if the acoustic events appear simultaneously and have similar parameters even if they are an effect of different failure mechanisms. In this research, we utilize an unsupervised learning algorithm besides the simplest K-means, through fuzzy c-means to Gaussian Mixture Model (GMM) and spectral clustering to investigate the dataset obtained from the three-point bending test manufactured by us composite. The analysis is preceded by data curation, feature determination (Laplacian score) and the best number of cluster investigations (DB index, Caliński-Harabasz score, and Silhouette method) To enable interpretation of the clustering we run an additional three groups of tests covering fibre breakage (two methods), resin fracture (in tension and in compression) and delamination (DCB test) creating reference datasets. These datasets were statistically analyzed and kernel density estimators were generated for each AE feature as well as amplitude-frequency characteristics. Clusters obtained for the main dataset were then assigned to particular causes of failure by comparing them with the reference dataset. It was found that clusters generated using spectral clustering were the most realistic ones, as it was possible to assign the cause of failure to them.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118596"},"PeriodicalIF":6.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Domenico Magisano, Leonardo Leonetti, Giovanni Garcea
{"title":"Optimal lamination angles via exact and efficient differentiation of the geometrically nonlinear finite element solution","authors":"Domenico Magisano, Leonardo Leonetti, Giovanni Garcea","doi":"10.1016/j.compstruct.2024.118579","DOIUrl":"10.1016/j.compstruct.2024.118579","url":null,"abstract":"<div><div>Laminates allow tailoring the fiber orientations in the layers to obtain the desired mechanical response. The optimal layup design is a challenging task in the case of finite deformations and buckling. For an assigned design, an incremental-iterative finite element analysis is needed to compute the structural response. Gradient-based methods are very often the most efficient optimization tools. Their bottleneck is the gradient evaluation, generally possible only approximately by finite differences. This article shows how to compute the exact gradient of the geometrically nonlinear finite element solution with respect to the stacking sequence. The strategy relies on the implicit differentiation of the nonlinear discrete equations of a control equilibrium point corresponding to an assigned displacement. This provides the load factor gradient by a single fast-solution linear system with the already factorized tangent stiffness matrix, regardless of the number of design variables, and scalar products involving the partial derivatives of the discrete internal force vector, calculated in an exact and efficient way. Several applications demonstrate the efficiency and robustness of the approach.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118579"},"PeriodicalIF":6.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bio-inspired discontinuous composite materials with a machine learning optimized architecture","authors":"Theodoros Loutas , Athanasios Oikonomou , Christoforos Rekatsinas","doi":"10.1016/j.compstruct.2024.118597","DOIUrl":"10.1016/j.compstruct.2024.118597","url":null,"abstract":"<div><div>Bio-inspired hierarchical discontinuous fibrous composite materials are investigated with the aim of achieving enhanced pseudo-ductility and elevated toughness. A novel methodology is proposed to search quickly and efficiently through the vast design space of the geometrical parameters of the discontinuities, combining advanced numerical simulations of the material’s mechanical behavior with state-of-the-art Machine Learning approaches, such as Active Learning. A continuum mesoscale-based numerical model is developed to simulate the mechanical behavior of discontinuous composites under three-point bending loading and is utilized in a sequential Bayesian optimization scheme that iteratively searches for the material architecture that maximizes toughness. Five independent geometrical variables related to the size and exact topology of the discontinuities form a vast five-dimensional design space of more than 2.6 million possible combinations. In this space, the proposed methodology efficiently identifies, after 100 iterations, a remarkable optimal configuration that increases the material’s toughness by more than 100%, with a knock-down effect on the ultimate bending strength of only 10%.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118597"},"PeriodicalIF":6.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007256/pdfft?md5=34dfb53e7afc868f36092a059bf5235c&pid=1-s2.0-S0263822324007256-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
María del Pilar de Urquijo-Ventura , Julio Alejandro Rodríguez-González , Carlos Rubio-González
{"title":"Mode I delamination monitoring in carbon nanotubes-glass fiber/epoxy composites using simultaneous electrical self-sensing and acoustic emission techniques","authors":"María del Pilar de Urquijo-Ventura , Julio Alejandro Rodríguez-González , Carlos Rubio-González","doi":"10.1016/j.compstruct.2024.118608","DOIUrl":"10.1016/j.compstruct.2024.118608","url":null,"abstract":"<div><div>The aim of this work is to demonstrate that simultaneous electrical resistance (ER) and acoustic emission (AE) techniques are a viable complementary procedures for in-situ mode I delamination monitoring of glass fiber/epoxy composite laminates containing multiwall carbon nanotubes (MWCNTs). The incorporation of MWCNTs was made by the spray-coating technique and composite laminates were manufactured by means of VARI process. The manufactured laminates were cut into double cantilever beam (DCB) specimens for fracture testing and simultaneous ER and AE measurements were carried out under mode I fracture loading condition. The results showed that the ER signal of the DCB specimens follows the load–displacement (P-δ) curve from initiation to growth of delamination failure, confirming the electrical self-sensing capability of the embedded MWCNT electrical network into the laminate. The correlation of AE events with the P-δ curves of the laminates with and without MWCNTs also allowed to detect the mode I delamination initiation and propagation. Although both the ER and AE techniques demonstrated their capability to determine mode I interlaminar fracture toughness and are in agreement with the results of ASTM standard, the presence of MWCNTs into laminates for self-sensing was more favorable since provided mechanical, electrical and sensing capabilities for SHM applications.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118608"},"PeriodicalIF":6.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0263822324007360/pdfft?md5=c6aec74e4fa5f5631c4dd0e6168abbed&pid=1-s2.0-S0263822324007360-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Failure mechanism investigation of the adhesively bonded joints using Finite Element and Discrete Element methods","authors":"Arman Abylkassimov , Gulnur Kalimuldina , Sherif Araby , Yerlan Amanbek","doi":"10.1016/j.compstruct.2024.118574","DOIUrl":"10.1016/j.compstruct.2024.118574","url":null,"abstract":"<div><div>Structural integrity is commonly defined by strength and durability of structure’s components. Adhesive joints have advantages over welding and bolted joints by less stress concentration, less weight and easier in manufacturing. In this study, numerical modelling analysis is employed to better understand fracture progression and its mechanism in adhesively bonded joints (lap shear joints) subjected to axial loading. Finite element method and discrete element method were used to predict strength and damage propagation of single lap joints. The study utilized Loctite EA 9497 epoxy as adhesive and three different adherends including polyphtalamide–polyphtalamide (PPA–PPA), aluminium–aluminium (AL–AL) and aluminium–polyphtalamide (AL–PPA) in the lap shear joints. The finite element model employed Cohesive Zone Model to examine joint strength, stress distributions along adhesive/adherend interface, and to perform scalar stiffness degradation analysis. The finite element model revealed that the adhesive damage takes place at the interface adjacent to the adherend with lower material stiffness. In addition, validation using load–displacement curves and comparison with experimental data demonstrated good agreement. Subsequently, discrete element model coupled with the Johnson–Kendall–Roberts (JKR) cohesion model was employed to adapted failure progression based on discrete particle interactions. The developed model was verified and compared with experimental results. Using the innovative discrete element method coupled with the JKR cohesion model, the bond number per particle parameter served as a material failure indicator. Analysis from the discrete element approach revealed that failure consistently takes place at the adhesive/adherend interface, irrespective of the adherend type. These study findings provide insights into investigating failure mechanisms in adhesively bonded joints at both macro- and micro-scales.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118574"},"PeriodicalIF":6.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Automatic modeling and optimization of tapered laminates with ply drops","authors":"Chen Du, Jiajun Chen, Qinghu Wang, Xiongqi Peng","doi":"10.1016/j.compstruct.2024.118603","DOIUrl":"10.1016/j.compstruct.2024.118603","url":null,"abstract":"<div><div>Ply-drop (PD) is the termination of specific plies for laminated composite structures to obtain continuous thickness changes. It brings flexibility to the design of tapered composite laminates. However, as a structural defect, ply drops could have an impact on performance. Considering the impact of ply drop during stacking sequence design can provide more accurate performance analysis, but this will bring challenges in modeling and optimization. To consider the PD impact and achieve convenience in optimization, this paper proposes a high-fidelity finite element automatic modelling method of tapered laminates and corresponding optimization framework. By parameterizing the PD information and defining the basic elements and nodes of start stacking surface of the structure, the entire finite element model is layer-wisely constructed and controllable. Subsequently, based on the genetic algorithm framework, a repair strategy and its genetic operations are proposed to ensure that the design variables satisfy the ply-drop design guidelines. And a detailed optimization process is provided. Finally, the strength and deflection performance optimization problem of a tapered laminate with PD from 28 layers to 16 layers under three-point bending test is introduced for illustration of the proposed automatic modeling and optimization method. Comparisons between simulation results and experimental data of the obtained optimization solution verify the effectiveness of the proposed modeling and optimization method.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"351 ","pages":"Article 118603"},"PeriodicalIF":6.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}