今日更新:Composite Structures 6 篇,Composites Part A: Applied Science and Manufacturing 3 篇,Composites Science and Technology 1 篇
Composite Structures
A bistable impact resistant sandwich carbon-fibre reinforced core
Francesco Flora, Marco Boccaccio, Fulvio Pinto, Michele Meo
doi:10.1016/j.compstruct.2023.117865
双稳态抗冲击夹层碳纤维增强内核
The interest of aerospace and automotive fields in the improvement of energy absorption properties of composite materials has stimulated researchers to design new typologies of cores of sandwich-structures under impact events. In this work, a sandwich structure based on pre-stressed bistable carbon fibre composite core is proposed. The core, named Circular Prestressed Carbon Core (CPCC), takes advantage of the asymmetric fibres orientation and the bistability-concept to enhance energy dissipation and reduce the damage extension during impacts. The impact campaign was conducted both experimentally and numerically to analyse the mechanical properties of the core and to study the contribution of the residual stresses. Experimental results were compared with an aerospace-grade aluminium honeycomb-core and a not-prestressed version of the core. Results proved its unique impact characteristics, showing, an improvement of the maximum-force up to 171% and 23% in comparison with aluminium honeycomb and not-prestressed CPCC, respectively. The specific properties of the CPCC were considerably higher than the aluminium sandwich, with peak force values up to +75%, displacement reduced up to -71%, and non-destructive evaluation (NDE) test showed a reduction of the projected damaged area by ∼20%. These results demonstrates that the CPCC structure constitutes a novel high-performance sandwich core for improved impact resistance.
Low-velocity impact response of the post-buckled FG-MEE plate resting on visco-Pasternak foundation: Magneto-electro-mechanical effects-based interaction analysis
Lizhi Li, Lu Nie, Yiru Ren
doi:10.1016/j.compstruct.2023.117869
粘滞-帕斯捷尔纳克地基上的后扣式 FG-MEE 板的低速冲击响应:基于磁机电效应的相互作用分析
Revealing the coupling of nonlinear behavior and the magneto-electro-mechanical effects in the impact responses of post-bucked magneto-electro-elastic structures contributes to the intelligent development of aircraft structural systems. The low-velocity impact responses of the post-buckled functional gradient magneto-electro-elastic(FG-MEE) plate resting on visco-Pasternak foundation are investigated. In the framework of the von Kármán-type nonlinear model considering post-buckling configurations, the low-velocity impact dynamics model of the post-buckled FG-MEE plate is constructed. The two-step perturbation method is developed to obtain the post-buckling equilibrium path induced by the magneto-electro-mechanical effects. Further, the higher-order form of the two-step perturbation method-Galerkin integral method is proposed for the post-buckled FG-MEE plate resting on visco-Pasternak foundation, acquiring the high-order truncated solutions of displacement, electric potential, and magnetic potential. Ultimately, the snap-through phenomenon of the post-buckled FG-MEE plate under low-velocity impact is captured, and the variation in the degree of coupling between nonlinear behavior and the magneto-electro-mechanical effects is systematically revealed.
The linear and nonlinear isogeometric finite element models of an axially functionally graded graphene platelet-reinforced composite (AFG-GPLRC) curved beam are established within the framework of the third-order shear deformation beam theory (TSDT) and von-Kármán’s nonlinear geometric relation. The AFG-GPLRC curved beams can be seen as composite structures in which the graphene platelets (GPLs) are continuously distributed in the matrix along the length direction of the curved beam according to different patterns. The modified Halpin-Tsai parallel model and the rule of mixture are implemented to predict the effective Young’s modulus and mass density as well as Poisson’s ratio, respectively. Hamilton's principle, TSDT, and von-Kármán’s strain-displacement relation are combined to derive the governing partial differential equation of motion and corresponding boundary conditions. Furthermore, the Non-Uniform Rational B-splines (NURBS)-based isogeometric analysis (IGA) approach together with a direct iterative technique are utilized to solve the nonlinear governing equation. The accuracy and efficiency of the proposed IGA framework are confirmed by comparing corresponding numerical solutions with other available results. The parametric investigations, such as the curved beam’s geometric parameters, boundary conditions, and GPL’s distribution patterns, on the nonlinear bending and vibration responses of the AFG-GPLRC curved beams are carried out by some illustrative examples.
An efficient surrogate model for damage forecasting of composite laminates based on deep learning
Guowen Wang, Laibin Zhang, Shanyong Xuan, Xin Fan, Bin Fu, Xiao Xue, Xuefeng Yao
doi:10.1016/j.compstruct.2023.117863
基于深度学习的复合材料层压板损伤预测高效替代模型
In this paper, full-field damage forecasting of a laminated composite structure subjected to different low velocity impact (LVI) conditions is realized through the proposed surrogate model, named VQ-SM. First, an efficient surrogate modelling method is proposed based on the advanced Vector Quantised-Variational AutoEncoder (VQ-VAE) proposed by DeepMind. Second, numerical simulation based on the progressive damage model of composite laminates is performed to obtain the training dataset. After training, the performance of VQ-SM is evaluated compared to the surrogate model without a representation learning process. The results show that VQ-SM has better performance with high-precise and good robustness, trained on the small dataset. Finally, the impact damage field of composite laminates is analyzed based on the surrogate model. The proposed surrogate modelling method provides not only the full-field damage forecast model for composite structures, but also an efficient method of improving the performance of the “generative” surrogate model.
Finite element analysis of the influence of dowel angle on CFRP anchors
José Luis Jiménez, Hernán Santa María
doi:10.1016/j.compstruct.2023.117866
锚栓角度对 CFRP 锚固件影响的有限元分析
In current retrofitting design guidelines, carbon fiber reinforced polymer (CFRP) anchors are recognized as an efficient and minimally invasive approach to delaying delamination. Recent research has demonstrated the capability of Finite Element Method (FEM) models to accurately reproduce the behavior of experimentally tested CFRP anchors. Among the various design parameters of CFRP anchors, the dowel angle is one of the least studied, yet it is a crucial factor. There is limited experimental data available for this parameter and there are no numerical models focused on its influence on anchor behavior. This article reports the results of a comprehensive three-dimensional FEM model for CFRP anchors, with a particular emphasis on varying dowel angles. The model accuracy is verified against direct shear joint tests drawn from the literature, including aspects such as the maximum load, load-slip curves, and the distribution of strains along the CFRP. Subsequently, the model is used to conduct a sensitivity analysis of the dowel angle in conjunction with other important parameters for the design of CFRP anchors. These parameters are the length of the CFRP ply behind the anchor, the number of anchors within the joint, the fiber content, and the depth of the dowel. The results obtained from the modeling show an important influence of the dowel angle on the effective use of carbon fibers and the enhancement of joint strength. By offering insights into the interactions between the dowel angle and other design parameters, this research contributes information that can guide the development of design guidelines for the optimization of CFRP anchor systems.
Mould Free Laminated Composites Using Eccentric Fibre Prestressing
Christopher Jenkins, Matthew J. Donough, B. Gangadhara Prusty
doi:10.1016/j.compstruct.2023.117867
使用偏心纤维预应力的无模层压复合材料
Mould free fibre reinforced composites are an emerging manufacturing process that allows for complex shapes to be produced, independently from complex moulding. Previous examples demonstrated reconfiguration through thermal stresses induced by an asymmetrical stacking sequence within a laminate. However, asymmetry within the laminate can adversely influence the stiffness and geometric coupling which results in heavier structures. This paper presents eccentric prestressing as a novel method to produce more structurally efficient mould free laminated composites. Euler-Bernoulli beam theory and finite element methods were employed to predict the strain and deformation of laminated composites with selective fibre prestress. The internal and external strains were measured with chirped fibre bragg grating sensors, and surface mounted strain gauges respectively to validate the numerical and analytical predictions where a difference of 3.13% was reported. Finally, a comparative study was conducted to show the benefits of eccentric prestress over asymmetric 4D printed laminates.
Development of polymer-based composites with excellent thermal conductivity and electrical insulation properties is a hot research topic, because more and more electrical devices with high energy/power density need thermal conductive electrical insulation systems. Polymers generally own lower thermal conductivity, and the composites filled with thermally conductive fillers is a common method for preparing high thermal conductivity composites. However, large amounts of fillers always result in decreasing of electrical insulation properties in the composites. Morphology control of the filler, complete core-shell structure, and core-shell-like structure fillers can achieve optimization of thermal conductivity and electrical insulation properties in filled composites. This work covers how to obtain a reasonable balance of thermal conductivity and electrical insulation properties in filled composites from the filler chosen of view. Recent advances in new thermally conductive fillers are summarized, to provide a reference for the application of high thermal conductivity composites in the electrical insulation field.
Efficient modelling of progressive damage due to quasi-static indentation on multidirectional laminates by a mesh orientation independent kinematically enriched continuum damage model
Manish Kumar, Supratik Mukhopadhyay
doi:10.1016/j.compositesa.2023.108002
通过与网格方向无关的运动学富集连续损伤模型,对多向层压板上的准静态压痕造成的渐进损伤进行高效建模
This work proposes a computationally efficient high-fidelity modelling framework for analysis of damage in composites subjected to quasi-static indentation. A ply-by-ply modelling approach is adopted, and a new semi-discrete continuum damage model is used for intra-ply cracking that allows for cracks to grow independent of the ply mesh pattern. This feature greatly simplifies the meshing effort since the requirement of a ply-oriented mesh and imposition of tie constraints at mesh-mismatched ply interfaces is eliminated. The model is further enhanced to realise kinematic interactions between the cracked and uncracked material domains at the constitutive level. Inter-ply delamination is simulated using cohesive elements. Through a challenging problem of static indentation on a quasi-isotropic laminate, it is shown that the model can capture solution-dependent multiple discrete ply cracks and detailed crack-delamination interaction, but with reduced computational time and complexity, compared to a reference model with ply-oriented mesh and pre-seeded cracks at known locations.
A comparative study of the cryogenic performance of CFRP composites with polyethersulfone/epoxy blends and electrospun polyethersulfone interleaves
Othman Laban, Garth Pearce, Jin Zhang, Mohammad S. Islam, Luke P. Djukic
doi:10.1016/j.compositesa.2023.108000
聚醚砜/环氧混合物和电纺聚醚砜交织物 CFRP 复合材料低温性能比较研究
Thermoslastic-modifers are used to enhance the fracture toughness of epoxy resins for cryogenic applications. This study presents a comparative analysis of the cryogenic performance of laminated fibre-reinforced composites, focusing on two different toughening approaches: interleaving electrospun polyethersulfone (PES) veils or epoxy/PES blends with varying PES loadings. In casted epoxy/PES blends, the particulate phase structure was formed with a PES content of 2.5-10 phr, transitioning to a co-continuous structure beyond 10 phr. Electrospun PES interleaves effectively enhanced interlaminar fracture toughness at both 293 and 77 K by 76% and 48%, respectively. These improvement levels achieved were comparable to those of laminates toughened with 7.5 phr PES/epoxy blend. The results presented suggest that interleaving composite laminates offers great potential in enhancing the durability of cryogenic tanks while being seamlessly integrated into manufacturing processes.
热塑性改性剂可用于增强环氧树脂在低温应用中的断裂韧性。本研究对层状纤维增强复合材料的低温性能进行了比较分析,重点关注两种不同的增韧方法:交错电纺聚醚砜(PES)纱或不同 PES 负载的环氧树脂/PES 混合物。在浇注环氧树脂/聚醚砜混合物中,聚醚砜含量为 2.5-10 phr 时会形成颗粒相结构,超过 10 phr 时会过渡到共连续结构。电纺聚醚砜交织层在 293 K 和 77 K 条件下分别有效提高了 76% 和 48% 的层间断裂韧性。这些改善水平与使用 7.5 phr PES/epoxy 混合材料增韧的层压板相当。研究结果表明,交错复合材料层压板在提高低温罐耐久性方面具有巨大潜力,同时可无缝集成到制造工艺中。
Zhicen Song, Yunwen Feng, Cheng Lu, Jiaqi Liu, Weihuang Pan
doi:10.1016/j.compscitech.2023.110414
基于自构建策略的增强 LSTM 方法,用于纤维增强聚合物非线性降解性能分析
The performance degradation of fiber-reinforced polymer (FRP) is a typical sequential data with a highly non-linear evolution pattern. In this study, a Self-constructed strategy-based reinforcement LSTM approach (short for SCRLA) is proposed to self-accommodate the non-linear sequential data, reduce modeling burden, and improve generalization ability. SCRLA incorporates Bayesian algorithms introducing the uncertainty of hyperparameter optimization by a probabilistic distribution of implicit objectives and self-constructed a high-dimensional, reinforced machine model that can learn and predict non-linear representations. In the case study, the datasets with different properties (one consisting of finite element analysis (FEA) results and one of real experimental (EXP) data) are selected to verify the validity of the degradation performance predictions. It is shown that the reinforced LSTM based on SCRLA is more suitable for the non-linear degradation performance analysis of FRP, especially with higher prediction accuracy for EXP data. The establishment of the approach and model provides a feasible idea and framework for the prediction of composites' sequential performance.