Progressive Damage Analysis of Random Chopped Fiber Composite Using Finite Elements

Author(s):  
Yi Pan ◽  
Assimina A. Pelegri

The mechanical properties of random chopped fiber composites are analyzed using micromechanical principles. A progressive damage model is adopted to investigate the damage and failure of the material. A representative volume element is generated numerically based on microscopic observations that capture the complex mesostructure of the random chopped fiber composite specimens. Sequentially, the mechanical properties are obtained using a micromechanics approach, particularly, the homogenization method. The underlying hypothesis insinuates that damage mechanisms such as matrix cracking, fiber damage, and interfacial debonding are responsible for the damaged behavior of the composite. Matrix cracking and fiber damage are modeled by progressive degradation of their respective stiffnesses. The interfacial debonding is modeled with a cohesive zone model. The prediction of uniaxial tensile response is compared with experimental data.

Author(s):  
Yi Pan ◽  
Assimina A. Pelegri

Fiber debonding in a bundled fiber reinforced polymer composite is investigated by using finite element method and cohesive zone model. Fiber and matrix are modeled as isotropic and linear elastic materials. Fiber/matrix interface is represented by a cohesive zone model governed by the traction-separation law. Effects of interfacial strength on interfacial debonding and stress field in the bundled fiber composite are examined. The stress field of the debonding composite is compared to that of perfectly bonded composite.


2019 ◽  
Vol 28 (10) ◽  
pp. 1457-1489 ◽  
Author(s):  
Seshadri Matta ◽  
Naresh Reddy Kolanu ◽  
Viswanath Chinthapenta ◽  
C M Manjunatha ◽  
M Ramji

In this paper, the in-plane compression behaviour of open-hole carbon fibre composite specimens adhesively bonded with the external carbon fibre composite patches on the single- and double side are studied. Uniaxial compression tests are conducted on MTS machine using ASTM anti-buckling fixture. A 3D progressive damage model is developed to predict the damage initiation and failure in both unrepaired open cutout and repaired carbon fibre composite specimens under compressive load. Stress-based 3D-Hashin's failure criteria are used for predicting the fibre and matrix damage in carbon fibre composite. The cohesive zone model element is used for modelling the interlaminar delamination in carbon fibre composite specimen and also the adhesive layer between patch and specimen. Initial stiffness, damage initiation load and ultimate load of the specimen are obtained using progressive damage model based on finite element analysis, and they are compared against the experimental values. The load–deflection curve and the damage progression obtained from finite element analysis using progressive damage model is found to be in good coherence with the experimental predictions. In case of patch bonded carbon fibre composite specimens, failure mechanism starts with partial patch debonding followed by complete specimen failure.


Author(s):  
Yi Pan ◽  
Assimina A. Pelegri

A micro-mechanics based finite element analysis method for random chopped fiber composites is applied. A modified random sequential adsorption technique is developed to generate representative volume elements of the composites so to overcome the “jamming limit” in the existing techniques. A homogenization scheme is applied to acquire the effective elastic constants of the composite. Two damage mechanisms are considered, matrix cracking and interfacial debonding, which occur prior to fiber breakage and consequentially leading to catastrophic failure. The incremental plastic model and the cohesive zone model are adopted to account for matrix plasticity and interfacial debonding, respectively. The finite element analysis results are validated by experimental data.


2020 ◽  
Vol 980 ◽  
pp. 107-116
Author(s):  
Hong Wang Zhao ◽  
Xiao Gang Liu ◽  
Abraham Kent

This paper expounds the basic theory of composite mechanics, and discusses the damage forms, damage analysis and failure criteria of composite materials. Then, the basic mechanical properties of unidirectional CFRP laminates with different layers, including modulus of elasticity, strength and so on, were obtained through a large number of experiments. Based on the experimental data, the relationship between the number of layers and the properties of materials was studied. The brittle fracture process of CFRP laminates was simulated by finite element analysis based on progressive damage model and compared with the force-displacement curves obtained by experiments. The validity of progressive damage model was proved.


2020 ◽  
Vol 57 (6A) ◽  
pp. 61
Author(s):  
Hoa Cong Vu

In this paper, a damage model using cohesive damage zone for the simulation of progressive delamination under variable mode is presented. The constitutive relations, based on liner softening law, are using for formulation of the delamination onset and propagation. The implementation of the cohesive elements is described, along with instructions on how to incorporate the elements into a finite element mesh. The model is implemented in a finite element formulation in ABAQUS. The numerical results given by the model are compare with experimental data


2011 ◽  
Vol 339 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Eric Lorentz ◽  
S. Cuvilliez ◽  
K. Kazymyrenko

2006 ◽  
Vol 324-325 ◽  
pp. 847-850 ◽  
Author(s):  
Cedric Lequesne ◽  
A. Plumier ◽  
H. Degee ◽  
Anne Marie Habraken

The fatigue behaviour of the welded beam-to-column connections of steel moment resisting frame in seismic area must be evaluated. The cohesive zone model is an efficient solution to study such connections by finite elements. It respects the energetic conservation and avoids numerical issues. A three-dimensional cohesive zone model element has been implemented in the home made finite element code Lagamine [1]. It is coupled with the fatigue continuum damage model of Lemaître and Chaboche [2]. The cohesive parameters are identified by the inverse method applied on a three points bending test modelling.


Author(s):  
Lijuan Liao ◽  
Toshiyuki Sawa ◽  
Chenguang Huang

The failure mechanism of scarf joints with a series of angles and brittle-ductile adhesives subjected to uniaxial tensile loads is analyzed by using a numerical method which employs a cohesive zone model (CZM) with a bilinear shape in mixed-mode (mode I and II). The adopted methodology is validated via comparisons between the present simulated results and the existing experimental measurements, which illustrate that the load-bearing capacity increases as the scarf angle decreases. More important, it is observed that the failure of the joint is governed by not only the ultimate tensile loads, but also the applied tensile displacement until complete failure, which is related to the brittle-ductile properties of the adhesive layer. In addition, failure energy, which is defined by using the area of the load-displacement curve of the joint, is adopted to estimate the joint strength. Subsequently, the numerical results show that the strength of the joint adopting ductile adhesive with higher failure energy is higher than that of the joint using brittle adhesive with lower failure energy.


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