A micromechanics-based damage model for compressive behavior analysis of impacted composite laminates

2019 ◽  
Vol 29 (3) ◽  
pp. 369-387 ◽  
Author(s):  
Xiaofei Lou ◽  
Xuecheng Han ◽  
Hongneng Cai

The compressive strength of composite laminates decreases seriously after being subjected to impact loading, which is an important item to be considered in the usage of composite material. In this paper, a micromechanics-based damage model is proposed to study the compressive behavior of impacted composite laminates. The micro stresses of fiber and matrix are calculated by stress amplification factors and then used to judge the failure mechanisms according to corresponding physical failure criteria. A progressive damage model based on different failure statuses of constituents is established to study the degradation of material properties. The bi-linear cohesive model is used in the research of delamination onset and propagation. The compressive behaviors of quasi-isotropic composite laminates subjected to different impact energies are investigated by this proposed method. Good agreements in terms of structure responses, failure mechanisms, and residual compressive strengths are obtained between numerical results and experimental data. The matrix cracking and delamination caused by impact loading are responsible for the initiation and propagation of buckling, which leads to the final collapse of entire laminates. Based on the numerical investigations of material parameters, the increment of mode II interlaminar fracture toughness is capable of improving the residual compressive strength significantly.

2016 ◽  
Vol 51 (10) ◽  
pp. 1433-1454 ◽  
Author(s):  
Paria Naghipour ◽  
Steven M Arnold ◽  
Evan J Pineda ◽  
Bertram Stier ◽  
Lucas Hansen ◽  
...  

The generalized method of cells (GMC) is demonstrated to be a viable micromechanics tool for predicting the deformation and failure response of laminated composites with and without notches subjected to tensile and compressive static loading. Given the axial [0], transverse [90], and shear [+45/−45] response of a carbon/epoxy (IM7/977-3) system, the unnotched and notched behavior of three multidirectional layups (1) Layup 1: [0,45,90,−45]2S, (2) layup 2: [60,0,-60]3S, (3) layup 3: [30,60,90,−30,−60]2S) are predicted under both tensile and compressive static loading. Matrix nonlinearity is modeled in two ways. The first assumes all nonlinearity is due to anisotropic progressive damage of the matrix only, which is modeled, using the multiaxial mixed mode continuum damage model (MMCDM) within GMC. The second utilizes matrix plasticity coupled with brittle final failure based on the maximum principle strain criteria to account for matrix nonlinearity and failure within NASA's multiscale framework (FEAMAC). Both MMCDM and plasticity models incorporate brittle strain and stress based failure criteria for the fiber. Upon satisfaction of this criterion, the fiber properties are immediately reduced to a nominal value. The constitutive response for each constituent (fiber/matrix) is characterized using a combination of vendor data and the axial, transverse and shear response of unnotched laminates. Then, the capability of the multiscale methodology is assessed, by performing blind predictions of the mentioned notched and unnotched composite laminates response under tensile and compressive loading. Tabulated data along with the detailed results (i.e. stress–strain curves as well as damage evolution states at various ratios of strain to failure) for all laminates are presented.


1993 ◽  
Vol 115 (1) ◽  
pp. 117-121 ◽  
Author(s):  
D. J. Thomas ◽  
R. C. Wetherhold

At a macroscopic level, a composite lamina may be considered as a homogeneous orthotropic solid whose directional strengths are random variables. Incorporation of these random variable strengths into failure models, either interactive or noninteractive, allows for the evaluation of the lamina reliability under a given stress state. Using a noninteractive criterion for demonstration purposes, laminate reliabilities are calculated assuming previously established load sharing rules for the redistribution of load as the failure of laminae occurs. The matrix cracking predicted by ACK theory is modeled to allow a loss of stiffness in the fiber direction. The subsequent failure in the fiber direction is controlled by a modified bundle theory. Results using this modified bundle model are compared with previous models, which did not permit separate consideration of matrix cracking, as well as to results obtained from experimental data.


2011 ◽  
Vol 306-307 ◽  
pp. 733-737
Author(s):  
Xu Dan Dang ◽  
Xin Li Wang ◽  
Hong Song Zhang ◽  
Jun Xiao

In this article the finite element software was used to analyse the values for compressive strength of X-cor sandwich. During the analysis, the failure criteria and materials stiffness degradation rules of failure mechanisms were proposed. The failure processes and failure modes were also clarified. In the finite element model we used the distributions of failure elements to simulate the failure processes. Meanwhile the failure mechanisms of X-cor sandwich were explained. The finite element analysis indicates that the resin regions of Z-pin tips fail firstly and the Z-pins fail secondly. The dominant failure mode is the Z-pin elastic buckling and the propagation paths of failure elements are dispersive. Through contrast the finite element values and test results are consistent well and the error range is -7.6%~9.5%. Therefore the failure criteria and stiffness degradation rules are reasonable and the model can be used to predict the compressive strength of X-cor sandwich.


2005 ◽  
Vol 297-300 ◽  
pp. 1303-1308 ◽  
Author(s):  
Jae Hoon Kim ◽  
Duck Hoi Kim ◽  
Hu Shik Kim ◽  
Byoung Jun Park

The objectives of this study are to evaluate the internal damage and compressive residual strength of composite laminate by impact loading. To investigate the environmental effects, as-received and accelerated-aged glass/phenolic laminates are used. UT C-Scan is used to determine the impact damage characteristics and CAI tests are carried out to evaluate quantitatively the reduction of compressive strength by impact loading. The damage modes of the woven glass/phenolic laminates are evaluated. In the case of the accelerated-aged laminates, as aging time increases, initial failure energy and residual compressive strength decrease.


2013 ◽  
Vol 387 ◽  
pp. 185-188
Author(s):  
Jian Yu Zhang ◽  
Ming Li ◽  
Li Bin Zhao ◽  
Bin Jun Fei

A progressive damage model (PDM) composed by 3D FEM, Hashin and Ye failure criteria and Changs degradation rules was established to deeply understand the failure of a new material system CCF300/5428 under low velocity impact. User defined subroutines were developed and embedded into the general FEA software package to carry out the failure analysis. Numerical simulations provide more information about the failure of composite laminates under low velocity impact, including initial damage status, damage propagation and final failure status. The history of the impact point displacement and various damage patterns were detailed studied.


2018 ◽  
Author(s):  
DC Pham

Composite laminates are susceptible to out-of-plane impact loads due to the lack of reinforcement in the through-thickness direction. Unlike the localized damage induced by a high velocity impact where the incident energy is dissipated near a contact area, low velocity impact damage involves multiple failure mechanisms such as matrix cracking, fiber breakage, and widespread interface delaminations. Depending on the extent of damage, significant reduction in the load-bearing capability of the structure has been observed. The prediction of composite impact damage resistance by a reliable progressive damage analysis tool is essential to reduce intensive and expensive certification tests at structural level. In this work, an enhanced explicit 3D damage model is implemented via VUMAT in Abaqus to perform a drop-weight impact simulation of a [454/04/-454/904]s Hexply AS4/8552 composite laminate. The impact-induced damage and its extent are captured by a 3D Continuum Damage Model (CDM) coupled with an energy driven failure mechanism. The developed module provides a unified solution process for the impact response prediction followed by the residual strength prediction under compression within an explicit solver. Two examples are selected to demonstrate the capability of the progressive failure analysis under dynamic and static loading: 1) a drop-weight test; and 2) an open-hole tension test. Numerical predictions from the developed VUMAT are compared with the test data and predictions using the open source CompDam code developed by NASA.


2019 ◽  
Vol 54 (2) ◽  
pp. 153-166
Author(s):  
Wenxuan Qi ◽  
Weixing Yao ◽  
Haojie Shen

A multidirectional damage model based on continuum damage mechanics for fiber-reinforced composite laminates is proposed in this paper. The influence of three main damage mechanisms, including transverse matrix cracking, local delamination, and fiber breakage, on the multidirectional stiffness properties of composite laminates is analyzed by introducing macro phenomenological damage variables. Then the mechanical behavior of elementary ply in laminates is modeled based on these damage variables. Besides, relations between micro-level damage variables and macro-level damage variables are established. Damage evolution laws of the three damage mechanisms are proposed to predict the degradation of multidirectional stiffness and failure strength of composite laminates under quasi-static loading. The experiment of cross-ply glass fiber-reinforced plastic laminates is carried out, and the prediction results show good agreement with the experimental results.


2011 ◽  
Vol 194-196 ◽  
pp. 1581-1585
Author(s):  
Chong Qiang Sun ◽  
Jian Yu Zhang ◽  
Bin Jun Fei

Progressive damage method is adopted to predict the static mechanics properties of FRP composite laminates with central hole. Progressive damage models with three different 3D failure criteria and material degradation models are established and analyzed via a user defined subroutine embedded into the general FEA package. Numerical results indicate that all the three 3D failure criteria can simulate the failure process of FRP laminates with central hole, but the final failure load is different. Degradation coefficient and the finite element mesh have significant effect on the numerical results.


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