Experimental and computational analysis of failure mechanisms in unidirectional carbon fiber reinforced polymer laminates under longitudinal compression loading
Abstract This study investigates the failure mechanisms of notched unidirectional (UD) carbon fiber reinforced polymer (CFRP) laminates subjected to longitudinal compressive loading. A sequence of failure initiation and propagation is observed based on optical microscopy images of specimens during failure. The micrographs reveal that the main failure mechanism in UD laminates is fiber kinking failure. The influence of manufacturing defects and voids on fiber kinking mechanisms is also analyzed. The results show that the voids in the resin-rich area lead to kink-band splitting, while in some cases the voids cause the kink-band to deflect in a new direction depending on the location of the voids. The next focus of this study is to propose a computational micromechanics model considering local fiber waviness to study the fiber kinking failure mechanism. The computational results on kink-band formation and stress-strain response show good consistency with our experimental analysis. Finally, the failure envelopes of σ 11 -σ 22 and σ 11 - τ 12 subjected to combined loading conditions are obtained from the computational model, which provide essential inputs for future theoretical failure criteria.
Abstract A multi-scale computational analysis based on representative volume element (RVE) modeling and molecular dynamics (MD) simulations is developed to investigate the microscopic failure mechanisms of unidirectional (UD) carbon fiber reinforced polymer (CFRP) composites. The average properties of the 200-nm thickness interphase region between fiber and matrix are characterized through MD simulations and an analytical gradient model. The results demonstrate that the interphase region has hig...
Abstract The effects of defects on lowering the compressive strength of thick unidirectional carbon fiber polymer matrix composites are reported here. Experimental results on specimens with specially designed defect shape and sizes are presented. A decrease in compressive strength is seen with an increase in both misalignment angle and defect height. Defect aspect ratio seems to influence the dominant mode of failure, with lower defect aspect ratio coupons showing propensity to kink, whereas, hi...
The key objective of this work is to highlight the effect of manufacturing-induced fiber waviness defects on the compressive failure of glass fiber-reinforced unidirectional specimens. For this purpose, in-plane, through-thickness waviness defects (with different waviness severities) are induced during the manufacturing of the laminate. Numerical and experimental results show that the compressive strength of the composites decreases as the severity of the waviness defects increases. A reduction ...
Last. Javier LLorca(UPM: Technical University of Madrid)H-Index: 13
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Abstract This review paper summarizes the current state-of-art and challenges for the future developments of fiber-reinforced composites for structural applications with multifunctional capabilities. After a brief analysis of the reasons of the successful incorporation of fiber-reinforced composites in many different industrial sectors, the review analyzes three critical factors that will define the future of composites. The first one is the application of novel fiber-deposition and preforming t...
Last. Raimund Rolfes(Leibniz University of Hanover)H-Index: 28
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Abstract The compressive failure of multidirectional laminates can be considered as an interaction of four failure mechanisms: fiber kinking, fiber splitting, matrix cracking and delamination. The interaction of these four failure mechanisms is responsible for the macroscopically observed nonlinear behavior and ultimate failure of the structure. In this paper, a numerically efficient 3D Finite Element modeling approach is presented combining the benefits of homogenizing material models and micro...
#1M. Bishara(Leibniz University of Hanover)H-Index: 2
#2Raimund Rolfes(Leibniz University of Hanover)H-Index: 28
Last. Olivier Allix(Université Paris-Saclay)H-Index: 28
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Abstract The fact that complex simulation can be carried out at present days allows to go further to answer new questions in the compressive failure of polymer composites. A thorough understanding of fiber kinking is essential for the prediction of stiffness and strength of fiber reinforced composites. The goal of this paper is to give a deep understanding of some topics which are still unclear in the micro modeling of fiber kinking. Such are the kinking mechanism and the difference in the kinki...
Abstract The determination of ply properties of Fiber Reinforced Polymers (FRP) for particular operational environmental conditions in aeronautical applications is mandatory in order to fulfill current industry stringent certification requirements. However, the traditional experimental approach requires massive investments of resources and time. From the behaviour obtained experimentally, constitutive equations including failure criteria are then devised to be used in the design of FRP structure...
Abstract We perform Monte Carlo analyses of the anisotropic viscoelastic response of random RVEs representing the microstructure of UD fibre composites. Both fibres and matrix are taken as isotropic viscoelastic solids; the fibres have different shapes including circular, elliptical, Reuleaux and star-shaped; they are separated from the matrix by interphase regions of different mechanical properties and thicknesses. The analyses allow determining the sensitivity of the transversely isotropic, vi...
Abstract A modified kink band model for compressive failure in fiber direction of fiber reinforced composite polymers was investigated and established in this study. Practically modifying the previous kink band model by logically applying a quadratic yield function combining transverse tensile and shear stress to the kinking instability, the modified model was able to determine the compressive strength along with the kink band failure angle theoretically. Especially in case of unidirectional car...
Abstract An experimental study on the axial compressive failure of cylindrical unidirectional (UD) carbon fibre-epoxy rods has been performed to better understand kink bands and the relevant damage mechanisms in three dimensions (3D). Post-mortem X-ray micro-computed tomography (micro-CT) imaging has shown that fibre kink bands predominantly all lie within the same plane in a cylindrical rod sample uniaxially compressed without lateral constraint. Kink bands at different stages of development ar...
Abstract In this study, integrated experimental tests and computational modeling are proposed to investigate the failure mechanisms of open-hole cross-ply carbon fiber reinforced polymer (CFRP) laminated composites. In particular, we propose two effective methods, which include width-tapered double cantilever beam (WTDCB) and fixed-ratio mixed-mode end load split (FRMMELS) tests, to obtain the experimental data more reliably. We then calibrate the traction-separation laws of cohesive zone model ...
Last. Brandon L. Ennis(SNL: Sandia National Laboratories)H-Index: 6
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Abstract An approach to increase the value of carbon fiber for wind turbines blades, and other compressive strength driven designs, is to identify pathways to increase its cost-specific compressive strength. A finite element model has been developed to evaluate the predictiveness of current finite element methods and to lay groundwork for future studies that focus on improving the cost-specific compressive strength. Parametric studies are conducted to understand which uncertainties in the model ...
Last. Wentao Yan(NUS: National University of Singapore)H-Index: 17
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Abstract Fused filament fabrication (FFF) with continuous carbon fiber filaments has proven to be a promising manufacturing technique in engineering applications. To provide guidance in the design of 3D printed carbon fiber reinforced polymer (CFPR) components, the longitudinal compression failure of continuous CFPR composites using the FFF technique is investigated systematically. First, longitudinal compression tests are performed for 3D printed continuous CFRP composites with and without desi...
Last. Weijian Han(Nanjing Tech University)H-Index: 1
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Abstract In this work, multi-scale finite element analyses based on three-dimensional (3D) hybrid macro/micro-scale computational models subjected to various loading conditions are carried out to examine the in-situ effect imposed by the neighboring plies on the failure initiation and propagation of cross-ply laminates. A detailed comparative study on crack suppression mechanisms due to the effect of embedded laminar thickness and adjacent ply orientation is presented. Furthermore, we compare th...
Fiber-reinforced composite structures are used in different applications due to their excellent strength to weight ratio. Due to cost and tool handling issues in conventional manufacturing processes, like resin transfer molding (RTM) and autoclave, vacuum-assisted resin transfer molding (VARTM) is the best choice among industries. VARTM is highly productive and cheap. However, the VARTM process produces complex, lightweight, and bulky structures, suitable for mass and cost-effective production, ...
#1Kangyi Lu(Huada: Beijing University of Chemical Technology)H-Index: 2
#2Wenmo Zhu(Huada: Beijing University of Chemical Technology)
Last. Xiaoping Yang(Huada: Beijing University of Chemical Technology)H-Index: 44
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Abstract Epoxy matrix with high modulus was synergistically designed by organic amide acid (AA) and inorganic nano silica (SiO2) as well as stiffened interphase of carbon fiber composite, and the effects of matrix modulus on longitudinal compressive strength and failure mechanism of composites were investigated. The elastic and shear modulus of matrix was enhanced by increased chemical cross-linking cites of AA and mechanical restraint of SiO2, contributing to improved interfacial properties fro...
Abstract A bottom-up multi-scale modeling approach is used to develop an Integrated Computational Materials Engineering (ICME) framework for carbon fiber reinforced polymer (CFRP) composites, which has the potential to reduce development to deployment lead time for structural applications in lightweight vehicles. In this work, we develop and integrate computational models comprising of four size scales to fully describe and characterize three types of CFRP composites. In detail, the properties o...
#1Bing Wang(HIT: Harbin Institute of Technology)H-Index: 24
#2Guodong Fang(HIT: Harbin Institute of Technology)H-Index: 14
Last. Shuo Liu(HIT: Harbin Institute of Technology)H-Index: 6
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Abstract The longitudinal compressive properties of carbon fiber/nanoparticles reinforced polymer unidirectional composites are investigated by experiments and a series of numerical simulations based on fast Fourier transforms (FFT) method taking into consideration matrix plastic behavior and initial fiber waviness. The efficient and accurate FFT-based method is convenient and has the low computation cost to discuss the effects of material and geometric parameters on the longitudinal compressive...
Last. Tong Earn Tay(NUS: National University of Singapore)H-Index: 28
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Abstract The prediction of compressive failure of composite laminates is generally more challenging than tensile failure, due to more complex failure mechanisms and nonlinear effects. This work presents an extension of a previously developed numerical framework utilizing discontinuous solid-shell elements and enriched cohesive elements for the simulation of damage growth of open-hole laminates under compression. Unlike tension, compressive loading may result in inclined matrix cracks due to loca...
Last. Jia-guang Meng(Xi'an Polytechnic University)H-Index: 2
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Recent increases in the use of carbon fiber reinforced plastics, especially for high-temperature applications, has induced new challenges in evaluating their mechanical properties. The effects of t...