Progressive Damage Simulation Research Articles

Progressive Damage Simulation of Wood Veneer Laminates and Their Uncertainty Using Finite Element Analysis Informed by Genetic Algorithms

Within the search for alternative sustainable materials for future transport applications, wood veneer laminates are promising, cost-effective candidates. Finite element simulations of progressive damage are needed to ensure the safe and reliable use of wood veneers while exploring their full potential. In this study, highly efficient finite element models simulate the mechanical response of quasi-isotropic [90/45/0/−45]s beech veneer laminates subjected to compact tension and a range of open-hole tension tests. Genetic algorithms (GA) were coupled with these simulations to calibrate the optimal input parameters and to account for the inherent uncertainties in the mechanical properties of wooden materials. The results show that the continuum damage mechanistic simulations can efficiently estimate progressive damage both qualitatively and quantitatively with errors of less than 4%.Variability can be assessedthrough the relatively limited number of 400 finite element simulations as compared to more data-intensive algorithms utilised for uncertainty quantification.

Bayesian parameter estimation for the inclusion of uncertainty in progressive damage simulation of composites

Despite gradual progress over the past decades, the simulation of progressive damage in composite laminates remains a challenging task, in part due to inherent uncertainties of material properties. This paper combines three computational methods — finite element analysis (FEA), machine learning and Markov Chain Monte Carlo — to estimate the probability density of FEA input parameters while accounting for the variation of mechanical properties. First, 15,000 FEA simulations of open-hole tension tests are carried out with randomly varying input parameters by applying continuum damage mechanics material models. This synthetically-generated data is then used to train and validate a neural network consisting of five hidden layers and 32 nodes per layer to develop a highly efficient surrogate model. With this surrogate model and the incorporation of statistical test data from experiments, the application of Markov Chain Monte Carlo algorithms enables Bayesian parameter estimation to learn the probability density of input parameters for the simulation of progressive damage evolution in fibre reinforced composites. This methodology is validated against various open-hole tension test geometries enabling the determination of virtual design allowables.

Finite Element Analysis Combined With Machine Learning to Simulate Open-Hole Strength and Impact Tests of Fibre-Reinforced Composites

Data-driven calibration techniques, consisting of theory-guided feed-forward neural networks with long short-term memory, have previously been developed to find suitable input parameters for the finite element simulation of progressive damage in fibre-reinforced composites subjected to compact tension and compact compression tests. The results of these machine learning-assisted calibration approaches are assessed in a range of virtual open-hole strength tests under tensile and compressive loadings as well as in low velocity impact tests. It is demonstrated that the calibrated material models with bi-linear softening are able to simulate the structural response qualitatively and quantitatively with a maximum error of 9[Formula: see text] with regards to experimentally measured open-hole strength values. Furthermore, the highly efficient models enable the virtual analysis of size effects as well as accurate force simulations in quasi-isotropic laminates under impact loading.

Meshfree simulation of progressive damage in composite laminates using discrete element analysis

This study presents a Discrete Element Method (DEM) for a meshfree progressive failure analysis of IM7/8552 carbon fibre reinforced polymer laminates at the macroscale. By implementing a cohesive contact model to describe progressive damage, experimental results from over-height compact tension (OCT) tests are used to calibrate the required input parameters in the DEM contact model. The simulation of various open-hole tension (OHT) test specimens validates the presented DEM model with minimal errors in strength predictions of up to 4%. Discrete Element Method results are directly compared to those obtained from finite element (FE) models. It is demonstrated that DEM is able to seemingly incorporate damage evolution leading to realistic macroscopic damage patterns, however the computational cost is increased by a factor of 100 compared to FE simulations.

Simulation of buckling-driven progressive damage in composite wind turbine blade under extreme wind loads

Wind turbine blades are continuously upscaled in size to meet the increasing demand of low cost renewable energy. The larger and slender blades with reduced mass are susceptible to large-deflection bending and instability during extreme wind gusts. The loading can induce interactive damage modes such as adhesive bond failure and composite skin damage progressively degrading the blade structural performance. The structural deformation and instability as well as progressive damage in composite blade is analyzed by developing finite element (FE) models using ANSYS software. First, a geometric nonlinear FE analysis of the 3D blade is performed to predict its deflection and regions of high stresses. The results demonstrated that high compressive stresses in the blade suction side trigger local skin buckling; thus initiating debonding of weak adhesive interface joint between skin and spar combined with skin damage. Subsequently, the interactive buckling-driven skin-spar debonding and composite skin damage in the identified region are analyzed through a submodel using cohesive zone model (CZM) as well as continuum damage mechanics (CDM) based progressive failure analysis, respectively, through a user-defined material subroutine. The results indicated that buckling-driven debonding of adhesive interface between skin and spar was primary damage mode leading to progressive failure of the blade composite skin. Consequently, the blade ultimate load carrying-ability was governed by coupled adhesive debonding and progressive skin damage phenomena, which is in good agreement with published experimental results. The developed simulation approach is capable to efficiently analyze the interactive buckling-induced interface damage as well as progressive failure of composite blade structure. In this work, modelling of interaction between interface debonding and skin damage, based on the CZM and CDM scheme, is a novel methodology for progressive damage analysis of blade under extreme loading.

Multi-fidelity progressive damage simulation of notched composite laminates with various ply thicknesses

In this study, a multi-fidelity fracture simulation scheme of composite laminates that accomplishes a seamless transition between medium- and high-fidelity crack models, namely, smeared crack models (SCMs) and discrete crack models (DCMs), is developed. The proposed scheme is based on the adaptive discrete-smeared crack (A-DiSC) method and a theoretical model for saturated crack density. The A-DiSC method first employs a DCM to model the transverse cracks in the laminates. If the crack density of each ply reaches the saturation value calculated using the theoretical model, the DCM is converted to an SCM. At this point, some cracks that are longer than a certain critical length remain explicitly modeled by the DCM, as they can significantly affect the subsequent path to final failure. By combining the two models, this method reduces the computational cost while preserving a sufficient prediction accuracy particularly in the case with numerous noncritical cracks up to failure. A simulation of the open-hole tensile test of composite laminates with various ply thicknesses was performed to verify the prediction accuracy of the developed scheme, and the predicted results were compared with the experimental results.

3D-printed thermoplastic composite fasteners for single lap joint reinforcement

This study presents findings for the strength and failure mechanism of a 3D-printed Continuous Carbon Fibre reinforced Onyx (CCF/Onyx) Thermo-Plastic Composite Fastener (TPCF) and a single lap-joint (SLJ) made of fibre/polymer composite reinforced by the TPCF. The study was carried out by numerical analysis and experiment methods including test sample design, manufacturing process and mechanical test. The 3D-printed fasteners were manufactured and tested in shear mode for two types of joining arrangement: fastened and hybrid bonded/fastened joints. Firstly, experiment was carried out for the TPCF fastened SLJ and the results show that addition of CCF in the Onyx matrix and post heat-treatment process could significant enhance the TPCF strength. The results was then benchmarked against a SLJ with steel fastening. The shear failure load of the SLJ reinforced by heat-treated CCF/Onyx TPCF of 8 mm diameter was 36% lower than a SLJ reinforced by a steel bolt of the same size. Numerical model for progressive damage simulation was also created based on the failure theory from Puck and Schürmann achieving good correlation with the experimental data. Secondly, the TPCF fasteners were manufactured with two types of heat-treated countersunk head and pan head forming and used to reinforce bonded SLJ. The test results show that the bonded SLJ reinforced by the TPCF fastener of countersunk head is of 11.7% higher strength and an increase in ultimate deformation by 9.1% compared to a bonded SLJ reinforced by steel fastener of 5 mm diameter. From the numerical and experimental study, it was noted that this was attributed to countersunk configuration to reduce out-out-plane bending and provide better crack arresting for the joint bonding.

Comparison of progressive damage simulation of 3D woven composites between voxel and conformal discretization models

This paper comprehensively compares the progressive damage simulation of 3D woven composites between the voxel and conformal mesh models. A progressive damage model for capturing the damage mechanisms of 3D woven composites is proposed, in which the longitudinal fiber fracture, transverse inter-fiber crack and matrix failure are detected by the Puck criterion, 3D hashin criteria and modified von Mises criterion, respectively. Benefiting from the periodicity of the woven architecture, a mesoscopic representative volume cell with high fidelity is constructed based on the microscope observations. The voxel and conformal meshing techniques are employed to discretize the periodic RVC model, and a mesh convergence analysis is performed to estimate the influence of element size. The comparison of the two discretization models is conducted in terms of fiber volume fraction, macroscopic stress-strain relations, damage developments and local stress fields. The results indicate that the damage initiations and developments obtained from voxel models are highly influenced by the spurious stress concentrations and artificial connections induced by the steplike elements.

A practical approach for the non-local simulation of progressive damage in quasi-isotropic fibre-reinforced composite laminates

This paper presents a generic strategy to generate macroscopic continuum damage models using non-local averaging. Formulation and derivation of such model are shown for dispersed quasi-isotropic IM7/8552 carbon fibre-reinforced composites. Experimental data and results from local damage simulations in over-height compact tension and compact compression tests are used to calibrate the non-local model for the simulation of progressive damage. A wide range of open–hole tension and compression tests validate these results. Thereby, different averaging radii are assessed in terms of prediction accuracy and computational efficiency. Besides the derivation of a practical relation of non-local damage parameters and fracture energy, it is shown that in these applications, non-local modelling enables the simulation of more realistic, mesh-independent damage. It is further concluded that the non-local averaging radius should be chosen to be small enough to avoid a significant increase of computational cost compared to local simulation methods.

Progressive damage simulation of 3D four-directional braided composites based on surface-interior unit-cells models

To accurately predict the longitudinal tensile mechanical properties of 3D four-directional braided composites, parameter modeling for surface and interior unit-cells mesoscopic solid models was implemented and the deviation of yarn spatial traces and squeeze deformation of yarn cross-section were considered in the surface unit-cell model. Voxel mesh was used to discrete models on which appropriate boundary conditions were imposed and damage models for each constituent of composites were added into a user-defined material subroutine (UMAT) in finite element analysis software ABAQUS. By simulation analysis of surface-interior unit-cells models for 3D four-directional carbon fiber/epoxy braided composites with 30° and 45° interior braiding angles respectively, using the volume-weighted average method, longitudinal tensile modulus and strength for braided composites specimens with different thicknesses were predicted. The progressive damage process of composites was studied by counting the number of integration points with the same damage modes. Results show that the longitudinal tensile mechanical properties predicted based on surface-interior unit-cells models for 3D four-directional braided composites agree well with experimental results, and damage analysis results reflect reasonably progressive damage process of surface and interior unit-cells.

Material model for simulation of progressive damage of composite materials using 3D Puck failure criterion

This paper describes the proposal and implementation of a material model in the commercial software Abaqus. The material model is capable of simulating progressive damage of composite materials. Progressive damage simulation is based on a stiffness matrix degradation and the 3D Puck failure criterion. Statistics of the input material parameters are simulated. The predictive capability of the material model was tested by a comparison of the numerical simulations to the tensile test of a laminate.

A computational approach with surface-based cohesive contact for meso-scale interface damage simulation in 3D braided composites

The yarn/yarn and yarn/matrix interface debonding has been recognized as a vital failure mode of 3 D braided composites. We present in this paper a meso-scale finite element (FE) model, which considers yarn/yarn and yarn/matrix interface debonding, for modeling progressive damage evolution of 3 D braided composites under typical tensile and shear loadings. In this setting, the damage state of braiding yarns and matrix is described through a continuum damage model (CDM) coupled with Murakami damage tensor; a bilinear traction-separation description is employed to govern the yarn/yarn and yarn/matrix interface behavior modeled by surface-based cohesive contact. We thus develop a user-material subroutine VUMAT (ABAQUS/Explicit) for our progressive damage simulation, including stress analysis, failure analysis and material properties degradation scheme. The mechanical properties of 3 D braided composites, and more importantly the damage evolution of interface debonding are thoroughly analyzed. The proposed FE modeling strategy provides a new perspective for the interface response study of other textile composites.

Progressive Damage Numerical Modelling and Simulation of Aircraft Composite Bolted Joints Bearing Response.

Finite element numerical progressive damage modelling and simulations applied to the strength prediction of airframe bolted joints on composite laminates can lead to shorter and more efficient product cycles in terms of design, analysis and certification, while benefiting the economic manufacturing of composite structures. In the study herein, experimental bolted joint bearing tests were carried out to study the strength and failure modes of fastened composite plates under static tensile loads. The experimental results were subsequently benchmarked against various progressive damage numerical modelling simulations where the effects of different failure criteria, damage variables and subroutines were considered. Evidence was produced that indicated that both the accuracy of the simulation results and the speed of calculation were affected by the choice of user input and numerical scheme.

Experimental and simulation investigation on BVID and CAI behaviors of CFRP laminates manufactured by RTM technology

Purpose The purpose of this paper is to synthetically investigate the impact damage responses of carbon fiber reinforced polymer (CFRP) and its influence on the compression mechanical responses of CFRP laminates, including damage distribution, residual compressive strength and fracture morphology. Design/methodology/approach A progressive damage simulation model is developed to analyze the complicated damage responses of CFRP laminates that are manufactured by resin transfer method (RTM) technology. Based on the ABAQUS/explicit finite element analysis solver, a VUMAT code is proposed to descript the composite materials’ damage behaviors under both impact and compression load. Adopting this proposed model, the primary mechanical indicators of four groups’ 5284RTM/U3160 CFRP laminates with different stacking sequences are predicted. Moreover, impact and compression after impact tests are conducted to verify the accuracy of simulation results. Findings Both simulation and experimental results show that the impact damage with low visible detectability can significantly reduce composites’ compressive strength. For all four groups’ composite laminates, the residual strength ratio is around 35% or even lower. The kernel impact damage near the plates’ geometric center promotes the degradation process of local materials and finally leads to the early occurrence of mechanical fracture. In addition, the impact damage projection area is not sensitive to the parameters of stacking sequences, while the residual compression strength is proportional to the number of 0-degree layers within whole laminates. Originality/value This study helps to understand the effect of an impact event on CFRP laminates’ compressive bearing capacity and provides a numerical method in simulating the damage responses under both impact and compression load.

Homogenization and localization of unidirectional fiber-reinforced composites with evolving damage by FVDAM and FEM approaches: A critical assessment

The recently-developed finite-volume direct averaging micromechanics (FVDAM) with progressive damage simulation capability modeled using the cohesive zone model is critically and fully assessed vis-à-vis Abaqus, a widely-adopted commercial finite-element code with cohesive element for the first time. The evolving debonding along the fiber/matrix interface of a unidirectional metal matrix composite is simulated using comparable bilinear traction-displacement separation laws in the two computational approaches. Differences between the two approaches are highlighted, including shortcomings of the Abaqus-based finite-element analysis of evolving damage. These shortcomings include the need of optimizing the compressive stiffness of the interface in order to: avoid material interpenetration; predict correct homogenized response; prevent numerical instabilities. These problems are not present in our version of the finite-volume homogenization approach since the traction-separation relations in the affected normal direction are directly eliminated when the interface is under compression. Nonetheless, comparison of the homogenized response and localized stress fields generated by the finite-element and finite-volume techniques demonstrates good agreement between the two approaches provided that a suitable compression factor is chosen in Abaqus.

A stacked sublaminate-based damage-plasticity model for simulating progressive damage in composite laminates under impact loading

We present a simple, efficient and easy-to-use finite element (FE) model for the simulation of progressive damage in quasi-isotropic IM7/8552 carbon fibre reinforced composites under low velocity impact loading. The sub-laminate based continuum-discrete model in the commercial FE software LS-DYNA consists of built-in tools to facilitate modelling and analysis. The coupled plastic-damage material card MAT81 describes intralaminar damage in tension and compression which is calibrated using digital image correlation in over-height compact tension and compact compression tests to extract damage properties such as strain softening curves and size of the failure process zone. The cohesive interface formulation is virtually calibrated leading to realistic zones of delamination. The proposed model was applied to a wide range of impact loadings and compared to results obtained from experimental testing and high-fidelity FE models. Besides the good correlation between simulation and experiments, we demonstrate how to quantify different energy dissipation mechanisms during impact events.

A three-dimensional stochastic progressive damage simulation model for polymer matrix-based laminate composites

This article proposes a three-dimensional (3D) stochastic progressive damage simulation model for the fiber-reinforced polymer matrix composite laminates. Constituents’ strength and fracture energy of each lamina were accounted as spatially varying random fields by 3D Karhunen–Loeve expansion method. Damage mechanisms modeled by continuum damage mechanics include internal damages of matrix and fiber. An anisotropic damage model was used for damage initiation and evolution of each lamina. By the proposed model, we investigated influences of variabilities in the lamina strength properties, and fracture energies along with delamination damage to the damage progression, strength, and post-failure behavior.

Damage evolution analysis of open-hole tensile laminated composites using a progress damage model verified by AE and DIC

A three-dimensional finite element model of composite laminates for progressive damage analysis has been established based on continuum damage mechanics. The model contains four kinds of damage modes of composite laminates under three-dimensional stress states, which include matrix damage, fiber breakage, delamination and fiber pull-out. Damage initiations adopt the mixed failure criterion composed by Linde criterion and Hashin criterion, which choose strain as parametric description. An improved exponential non-linear evolution model is adopted for damage variables, which take into account the effect of material dissipated energy on the damage variables. The damage variables calculated by material dissipated energy are different from that calculated by fracture dissipation energy employed by Linde, the material dissipated energy is the result of various damage accumulation of composite material, which can reflect the gradual damage evolution process of material. The progressive damage simulations have been performed to investigate damage evolution of unidirectional laminate and bidirectional laminate with a hole under tension, the damage evolutions simulated by FEA have a good agreement with that obtained from real-time acoustic emission (AE), digital image correlation (DIC) monitoring and load–displacement relationship, which validate efficiency of the proposed 3D FEM model.

Progressive damage simulation for a 3D-printed curvilinear continuous carbon fiber-reinforced thermoplastic based on continuum damage mechanics

Continuum damage mechanics (CDM) based on finite element analysis was performed to predict the mechanical behavior of a 3D-printed curvilinear continuous carbon fiber reinforced thermoplastic (c-CFRTP). Elastoplastic properties of the 3D-printed c-CFRTP including damage initiation, evolution, and propagation were identified using monotonic and cyclic tensile tests for three specimens, i.e. [(±45)2]S, [(0/90)2]S, and [(±67.5)2]S. Then, S-shaped curvilinear c-CFRTP was 3D-printed and tested in monotonic tensile loading. The non-linear mechanical behavior of an S-shaped curvilinear c-CFRTP due to tensile loading was well predicted by means of finite element analysis using the constructed CDM-based material model.

Numerical analysis of mechanical behavior of unidirectional thermoplastic-based carbon fiber composite for 3D-printing

The paper is dedicated to the simulation of mechanical behavior of a unidirectional thermoplastic-based composite material reinforced with carbon fibers. The influence of microstructure imperfections on mechanical characteristics of the composite material has been studied, and numerical parameters that ensure a good correlation between nonlinear two-scale simulation of progressive damage and experimental data have been identified. Results of the study revealed limited importance of accounting for such imperfections of composite microstructure as deviation in fiber laying direction and fiber curvature. The two-scale simulation approach based on submodeling technique was proved to describe the nonlinear behavior of the thermoplastic-based carbon fiber material with a reasonable accuracy.