A numerical micro-mechanical study on damage induced by the curing process in carbon/epoxy unidirectional material

Danzi, Federico; Fanteria, Daniele; Panettieri, Enrico; Mancino, M.C.

doi:10.1016/j.compstruct.2018.11.059

Cited by 27 publications

(28 citation statements)

References 28 publications

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“…Such defects can degrade the in situ matrix properties significantly and therefore, affect the composite mechanical response during subsequent load applications [ 16 , 17 , 18 , 19 , 20 , 21 ]. Despite these significant research contributions, a knowledge gap exists on the evolution of these process-induced uncertainties and their influence on the composite mechanical response such as transverse tensile [ 17 , 18 , 19 , 20 , 22 , 23 ] and compressive response [ 17 , 24 ]. It is paramount to address these knowledge gaps with novel and reliable process modeling approaches.…”

Section: Introductionmentioning

confidence: 99%

“…Computational micromechanics is an emerging field that leverages the advances in finite element methods (FEM) and the ever-increasing computing capabilities to accurately predict the microscale response of composite representative volume elements (RVEs) when subjected to various thermo-mechanical boundary conditions [ 16 , 17 , 18 , 19 , 20 , 21 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Within this framework, process-induced residual stress generation and damage accumulation can be obtained, and their influence on the bulk composite properties can be investigated by means of virtual curing and mechanical loading simulations of RVEs.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the prediction of the stress and strain microfields throughout the microstructure allow precise estimations of stress concentration, damage initiation, and propagation during curing and subsequent mechanical loading. Several numerical studies have been performed to characterize the generation of process-induced residual stresses and evaluate their effect on the processed composite performance [ 16 , 17 , 18 , 19 , 20 , 21 , 23 , 24 , 25 , 26 , 27 , 29 ]. These studies most commonly utilize the phenomenological cure kinetic model, introduced by Kamal [ 30 ], along with the Fourier’s heat transfer law to define the progression of cure, heat generation, and heat conduction in the PMCs during cure.…”

Section: Introductionmentioning

confidence: 99%

“…These studies most commonly utilize the phenomenological cure kinetic model, introduced by Kamal [ 30 ], along with the Fourier’s heat transfer law to define the progression of cure, heat generation, and heat conduction in the PMCs during cure. Coupled thermo-mechanical analysis with appropriate constitutive models have been used to predict residual stresses in composite microstructures including incremental elasticity model [ 31 , 32 ], linear mixing rule based on composite laminate plate theory [ 33 ], instantaneous linear elastic models [ 16 , 17 , 18 ], CHILE model [ 24 ], linear and nonlinear visco-elastic models [ 34 , 35 , 36 , 37 , 38 ], elasto-plastic model [ 23 , 26 ], network-based model [ 19 , 20 , 22 , 39 , 40 ], columnar model [ 29 ], and analytical models [ 41 ]. Some studies have investigated the effect of process-induced residual stresses on the bulk composite response under different loading scenarios.…”

Section: Introductionmentioning

confidence: 99%

“…These studies demonstrated that process-induced residual stresses affected the in situ matrix properties and the effective stiffness and strength of the composite. More recently, Danzi et al [ 23 ] integrated the network model proposed by Heinrich et al [ 40 ] to estimate matrix shrinkage and elastic property evolution during cure with damageable elasto-plastic constitutive relations, to emphasize on the importance of the curing process in damage analysis of composites. On similar lines, Hui et al [ 24 ] developed an analytical numerical framework and investigated the effect of residual stresses on the transverse compressive response of IM7/8552 RVEs under quasi-static and dynamic test conditions.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Manufacturing on the Transverse Response of Polymer Matrix Composites

Shah

Maiarù

2021

Polymers

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The effect of residual stress build-up on the transverse properties of thermoset composites is studied through direct and inverse process modeling approaches. Progressive damage analysis is implemented to characterize composite stiffness and strength of cured composites microstructures. A size effect study is proposed to define the appropriate dimensions of Representative Volume Elements (RVEs). A comparison between periodic (PBCs) and flat (FBCs) boundary conditions during curing is performed on converged RVEs to establish computationally efficient methodologies. Transverse properties are analyzed as a function of the fiber packing through the nearest fiber distance statistical descriptor. A reasonable mechanical equivalence is achieved for RVEs consisting of 40 fibers. It has been found that process-induced residual stresses and fiber packing significantly contribute to the scatter in composites transverse strength. Variation of ±5% in average strength and 18% in standard deviation are observed with respect to ideally cured RVEs that neglect residual stresses. It is established that process modeling is needed to optimize the residual stress state and improve composite performance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of Manufacturing on the Transverse Response of Polymer Matrix Composites

Shah

Maiarù

2021

Polymers

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Influence of the cure state on mechanical properties of an epoxy‐based adhesive: Experimental characterization and numerical simulation

Teixeira

Akhavan‐Safar

Carbas

et al. 2021

Polymers for Advanced Techs

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Heat curing epoxy‐based adhesives are extensively used in primary bonded structures. The manufacturing process of joints with heat curing adhesives is commonly made with isothermal processes where a large curing time is set to guarantee the complete curing of the adhesive. The aim of the current study is to investigate the influence of the curing state on the tensile mechanical properties of a structural one‐component epoxy based adhesive. To achieve this, tensile tests on bulk adhesive dog‐bone coupons with incomplete curing were performed. The process cycle was adjusted to achieve the desired curing degree for testing. The curing process was simulated by using the Kamal kinetics model calibrated with differential scanning calorimetry (DSC) tests. The results show that the curing process is very sensitive to the curing temperature, requiring a low curing temperature to control process duration. A good correlation between the estimated curing degree and the final obtained curing measured with the Fourier‐transform infrared spectroscopy FTIR was found. Regarding the mechanical properties, the elastic modulus and the tensile strength are reduced at lower curing degrees making the material softer and more ductile. The loss in the mechanical properties shows to be consistent with the measurements performed with dynamical mechanical analyses (DMA) by measuring the evolution of the elastic modulus with the curing degree. In this way, the numerical simulation of the curing process seems to be a valuable tool to predict the final performance of adhesive, and design the curing cycle.

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An efficient viscoelastic multiscale model for investigation on the cure‐induced microscopic residual stresses of composite laminates

Liu,

Cao

et al. 2024

Polymer Composites

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The cure‐induced residual stresses have a significant influence on the deformation and mechanical properties of composites. Moreover, the cure‐induced residual stresses exhibit multi‐level and multiscale distributions due to the complexity of micro‐structure of composites and anisotropic characteristics. In this paper, a computationally efficient multiscale procedure is proposed to predict the microscopic residual stresses induced by cure temperature, cure shrinkage and macroscopic residual stresses, which is based to the linear viscoelastic theory combined with the micro‐mechanics method. The instantaneous microscopic residual stresses are expressed as a linear combination of the instantaneous temperature increment, degree of cure increment and macroscopic strain increment at all times of the cure process until to the current time. The proposed method is verified in comparison with the published results in literature and the microscale FEA at different length scales, respectively. The results show that the proposed method is about a thousand times faster than directly using FEA in the microscale RVE model once the influence coefficient matrices are determined. At length, the microscale stresses of all nodes of the entire macroscale model are examined by using the proposed method. It is found that the thermal‐chemical‐mechanical loads lead to serious microscopic stresses for the matrix and interphase constituents, especially for those due to the macroscopic residual stresses.Highlights Microscale residual stress is written as a linear combination of macroscale loads. Applying macroscale loads on microscale FEA model to obtain influence matrices. The presented model avoids repeatedly FEA microscopic to improve the efficiency. The online time required for the proposed model is much less than microscale FEA. The microscale stress increases the risk of matrix cracking and interface bonding.

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A numerical micro-mechanical study on damage induced by the curing process in carbon/epoxy unidirectional material

Cited by 27 publications

References 28 publications

Effect of Manufacturing on the Transverse Response of Polymer Matrix Composites

Effect of Manufacturing on the Transverse Response of Polymer Matrix Composites

Influence of the cure state on mechanical properties of an epoxy‐based adhesive: Experimental characterization and numerical simulation

An efficient viscoelastic multiscale model for investigation on the cure‐induced microscopic residual stresses of composite laminates

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