scholarly journals High Cycle Fatigue Damage Model for Delamination Crack Growth in CF/Epoxy Composite Laminates

2010 ◽  
Vol 20 (5) ◽  
pp. 783-807 ◽  
Author(s):  
Laurent Gornet ◽  
Hassan Ijaz
2014 ◽  
Vol 941-944 ◽  
pp. 1477-1482
Author(s):  
Xu Tao Nie ◽  
Wan Hua Chen ◽  
Yuan Xing Wang

High-cycle fatigue damage analysis and life prediction is a most crucial problem in the research field of solid mechanics. Based on the thermodynamic potentials in the framework of thermodynamics a numerical method for high-cycle fatigue damage was studied and provided by using a two-scale damage model. Furthermore, according to the “jump-in-cycles” procedure the numerical simulation of high-cycle fatigue damage was implemented in a user subroutine of ABAQUS software. Finally, a numerical simulation instance of high-cycle fatigue damage was provided and compared with a set of test data, which indicates that the numerical simulation method presented is reasonable and applicable.


2011 ◽  
Vol 326 ◽  
pp. 37-52 ◽  
Author(s):  
Hassan Ijaz ◽  
M Aurangzeb Khan ◽  
Waqas Saleem ◽  
Sajid Raza Chaudry

This paper presents the mathematical modelling of fatigue damage able to carry out simulation of evolution of delamination in the laminated composite structures under cyclic loadings. A new elastic fatigue damage evolution law is proposed here. A classical interface damage evolution law, which is commonly used to predict static debonding process, is modified further to incorporate fatigue delamination effects due to high cycle loadings. The proposed fatigue damage model is identified using Fracture Mechanics tests like DCB, ENF and MMB. Simulations of delamination under fatigue loading are performed and results are successfully compared with reported experimental data on HTA/6376C unidirectional material. Delamination crack growth with variable fatigue amplitude is also performed and simulation results show that the proposed fatigue damage law can also accommodate this variable amplitude phenomenon. A study of crack tip behaviour using damage variable evolution is also carried out in this paper. Finally the effect of mesh density on crack growth is also discussed.


2016 ◽  
Vol 697 ◽  
pp. 658-663
Author(s):  
Rong Guo Zhao ◽  
Ya Feng Liu ◽  
Yong Zhou Jiang ◽  
Xi Yan Luo ◽  
Qi Bang Li ◽  
...  

The high cycle fatigue tests for smooth specimens of TC25 titanium alloy under different stress ratios are carried out on a MTS 809 Material Test Machine at a given maximum stress level of 917MPa at ambient temperature, the high cycle fatigue lifetimes for such alloy are measured, and the effects of stress amplitude and mean stress on high cycle fatigue life are analyzed. The initial resistance is measured at the two ends of smooth specimen of TC25 titanium alloy, every a certain cycles, the fatigue test is interrupted, and the current resistance values at various fatigue cycles are measured. The ratio of resistance change is adopted to characterize the fatigue damage evolution in TC25 titanium alloy, and a modified Chaboche damage model is applied to derive the fatigue damage evolution equation. The results show that the theoretical calculated values agree well with the test data, which indicates that the modified Chaboche damage model can precisely describe the accumulated damage in TC25 titanium alloy at high cycle fatigue under unaxial loading. Finally, the high cycle fatigue lifetimes for TC25 titanium alloy specimens at different strain hardening rates are tested at a given stress ratio of 0.1, the effect of strain hardening on fatigue life is investigated based on a microstructure analysis on TC25 titanium alloy, and an expression between fatigue life and strain hardening rate is derived


2012 ◽  
Vol 570 ◽  
pp. 25-36 ◽  
Author(s):  
Hassan Ijaz ◽  
L. Gornet ◽  
M.A. Khan ◽  
W. Saleem ◽  
K. Nisar ◽  
...  

The global behavior of composite materials is strongly influenced by the quality of adhesion between different components. A component can be single phase, like fibers or particles used as reinforcement in a homogenous matrix, or a multiphase material like a layer in long-fiber laminate. In the latter case the degradation of adhesion implies the separation of the layers, known as delamination. Among all different failure mechanisms, Delamination is considered to be the most prominent mode of failure in fiber-reinforced laminates as a result of their relatively weak inter-laminar strength. When laminated structures are subjected to static, dynamic or cyclic loadings, the inter-laminar adhesion strength between individual plies tends to deteriorate significantly and act as the origin of the final failure. Therefore, an efficient and reliable design tool capable of predicting delamination could improve the durability for composite laminates. There exist damage mechanics based formulations capable of simulating the delamination crack growth in carbon/glass fiber epoxy based composite laminates. The present study is focused on taking a step forward in this respect. At first, already existed local interface models effectiveness is tested and results are successfully compared with available experimental data for UD IMS/924 Carbon/fiber epoxy composite laminate. Next, a non-local integral-type regularization scheme is introduced to overcome the spurious localization problem associated to the existing local model. Basic concepts and mathematical modeling of Non-Local damage evolution law are comprehensively studied and presented in this study. Finite Element simulation results based on proposed model are discussed in detail and are compared with experimental results.


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