Finite element simulation technique for evaluation of opening stresses under high plasticity

Author(s):  
Ans Al Rashid ◽  
Ramsha Imran ◽  
Zia Ullah Arif ◽  
Muhammad Yasir Khalid

Abstract The crack closure phenomenon is important to study as it estimates the fatigue life of the components. It becomes even more complex under low cycle fatigue (LCF) since under LCF high amount of plasticity is induced within the material near notches or defects. As a result, the assumptions used by the linear elastic fracture mechanics (LEFM) approach become invalid. However, several experimental techniques are reported on the topic, the utilization of numerical tools can provide substantial cost and time-saving. In this study, the authors present a finite element simulation technique to evaluate the opening stress levels for two structural steels (25CrMo4 and 30NiCrMoV12) under low cycle fatigue conditions. The LCF experimental results were used to obtain kinematic hardening parameters through the Chaboche model. The finite element analysis (FEA) model was designed and validated, following the fatigue crack propagation simulation under high plasticity conditions using ABAQUS. Crack opening displacement vs. stress data was exported from ABAQUS, and 1.5% offset method was employed to define opening stress levels. Numerical simulation results were compared with the experimental results obtained earlier through the digital image correlation (DIC) technique. To conclude, FEA could be a valuable tool to predict crack closure phenomena and, ultimately, the fatigue life of components. However, analysis of opening stresses using crystal plasticity models or extended finite element method (XFEM) tools should be explored for a better approximation in future studies.

2020 ◽  
Author(s):  
Ans Al Rashid ◽  
Ramsha Imran ◽  
Muhammad Yasir Khalid

Abstract The mechanical behavior of materials plays a vital role in the structural performance of designed structures. Therefore, significant resources are devoted globally towards experimental characterization of material behavior, especially for the experiments requiring particular protocols. Contrary, finite element analysis tools have made a substantial contribution to the design of structural elements, which could conserve a significant amount of resources and material wastage. Evaluation of fatigue life of materials is necessary to predict the life expectancy of the structures precisely, and opening stress levels under fatigue loading contributes towards this evaluation. Railways serve as freight and passenger carrier transportation modes. The railway axles contribute as the primary load-carrying element; therefore, the design of railway axles and the study of their mechanical behavior under repeated loading is vital. In this study, the authors present a finite element simulation technique to evaluate the opening stress levels for two structural steels subjected to low cycle fatigue. The finite element analysis (FEA) model was designed and validated following the simulation of fatigue crack propagation under high plasticity conditions. Numerical simulation results were compared with the experimental results obtained earlier through the digital image correlation (DIC) technique. To conclude, FEA could be a useful tool to predict crack closure phenomena and, ultimately, the fatigue life of components. However, researchers need to establish more sophisticated numerical tools for more precise results in case of high plasticity conditions near the crack tip.


2014 ◽  
Vol 86 ◽  
pp. 158-165
Author(s):  
J. De ◽  
S. Bhattacharjee ◽  
S. Dhar ◽  
S.K. Acharyya ◽  
S.K. Gupta ◽  
...  

2016 ◽  
Vol 58 (2) ◽  
pp. 329-349 ◽  
Author(s):  
Rui Zhang ◽  
Lihua Wen ◽  
Sam Naboulsi ◽  
Thomas Eason ◽  
Vijay K. Vasudevan ◽  
...  

2014 ◽  
Vol 875-877 ◽  
pp. 1116-1120
Author(s):  
Wen Liang Li ◽  
Wei Zhou ◽  
Li Gao ◽  
Wei Liang Dai

With finite element simulation method, the fatigue life of vehicle front floor is analyzed in different vehicle wheelbases and velocities, and the washboard enhancement coefficient is calculated, then K-v curve, K-m curve and K-v-m surface are drawn, with which influence of vehicle velocity and wheelbase on washboard enhancement coefficient is studied. The study results show that, when the wheelbase is constant, washboard enhancement coefficient increases first and then decreases with velocity increasing, and reaches peak at a certain velocity; when velocity is constant, washboard enhancement coefficient decreases as wheelbase increasing; when velocity and wheelbase both changes, washboard enhancement coefficient varies in K-v-m surface.


2006 ◽  
Vol 505-507 ◽  
pp. 739-744
Author(s):  
Yuan Chuan Hsu ◽  
Tung Sheng Yang ◽  
J.L. Wu ◽  
Y.X. Chen

Currently, tube hydroforming and metal micro-forming technique have emerged as the attractive and important developing tendencies in industry. Hence, in this study, the finite element simulation technique was employed to investigate the micro-hydroforming for making the micro-square tube with non-equal section and dendritic shape from square tube. Results of the current study show that the deformation of micro-square tube can be effectively analyzed by finite element simulation. The bulging and wall thinning of the tube are severely influenced not only by the internal hydraulic pressure but also by the punch axial feeding speed.


2005 ◽  
Vol 297-300 ◽  
pp. 96-101
Author(s):  
Ishak Abdul Azid ◽  
Lee Kor Oon ◽  
Ong Kang Eu ◽  
K.N. Seetharamu ◽  
Ghulam Abdul Quadir

An extensively published and correlated solder joint fatigue life prediction methodology is incorporated by which finite element simulation results are translated into estimated cycles to failure. This study discusses the analysis methodologies as implemented in the ANSYSTM finite element simulation software tool. Finite element models are used to study the effect of temperature cycles on the solder joints of a flip chip ball grid array package. Through finite element simulation, the plastic work or the strain-energy density of the solder joints are determined. Using an established methodology, the plastic work obtained through simulation is translated into solder joint fatigue life [1]. The corresponding results for the solder joint fatigue life are used for parametric studies. Artificial Neural Network (ANN) has been used to consolidate the parametric studies.


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