Fatigue damage evolution analysis of the CA mortar of ballastless tracks via damage mechanics-finite element full-couple method

2021 ◽  
Vol 295 ◽  
pp. 123679
Author(s):  
Shijie Deng ◽  
Juanjuan Ren ◽  
Kai Wei ◽  
Wenlong Ye ◽  
Wei Du ◽  
...  
2014 ◽  
Vol 707 ◽  
pp. 390-396
Author(s):  
Xian Min Chen ◽  
Di Guan ◽  
Feng Ping Yang

A damage accumulation model is presented for fatigue life prediction of metallic structures. Based on the energy theory and material fatigue test data, the plastic strain threshold for damage initiation was modified for HCF and LCF respectively. The damage evolution parameters were determined according to the fatigue test results of standard specimens. A damage mechanics-finite element full-couple method was adopted to simulate the process of fatigue damage evolution, incorporating elastic modulus reduction due to fatigue damage. Comparisons are made with the fatigue tests of 2A12-T4 open-hole plates and good agreement was obtained.


2007 ◽  
Vol 348-349 ◽  
pp. 761-764
Author(s):  
Tai Quan Zhou ◽  
Yuan Hua ◽  
Tommy Hung Tin Chan

The finite element analysis fully coupled fatigue damage evolution is implemented on the user subroutine UMAT of the finite element software ABAQUS. The fully coupled method developed with damage mechanics and the finite element analysis is performed on calculation of fatigue damage accumulation of the critical welded member in the Tsing Ma Bridge. The calculated result shows that the fatigue damage in the critical welded member is accumulated in the region of toe of welding. The value of faitgue life calculated by the fully coupled method is smaller than that by the uncoupled method, which suggests that there exists interaction between the fatigue damage evolution and the structural response. The linear Miner’s Law is widely used however conservative for the evaluation of fatigue life of bridge on service. The above results provide feasible method for accurate evaluation of fatigue damage in bridge components based on the hot spot stress analysis and the damage mechanics theory.


2015 ◽  
Vol 750 ◽  
pp. 266-271 ◽  
Author(s):  
Yu Zhou ◽  
Xue Dong Chen ◽  
Zhi Chao Fan ◽  
Yi Chun Han

The creep behavior of 2.25Cr-1Mo-0.25V ferritic steel was investigated using a set of physically-based creep damage constitutive equations. The material constants were determined according to the creep experimental data, using an efficient genetic algorithm. The user-defined subroutine for creep damage evolution was developed based on the commercial finite element software ANSYS and its user programmable features (UPFs), and the numerical simulation of the stress distribution and the damage evolution of the semi V-type notched specimen during creep were studied. The results showed that the genetic algorithm is a very efficient optimization approach for the parameter identification of the creep damage constitutive equations, and finite element simulation based on continuum damage mechanics can be used to analyze and predict the creep damage evolution under multi-axial stress states.


Author(s):  
Yi Zhang ◽  
P-Y Ben Jar ◽  
Shifeng Xue ◽  
Lin Li

A phenomenon-based hybrid approach of experimental testing and finite element simulations is used to describe the fracture behavior of pipe-grade polyethylene. The experimental testing adopts a modified D-split test method to stretch the pipe ring (notched pipe ring) specimens that have symmetric, double-edged flat notches along the pipe direction. Two series of experimental testing were conducted: (1) monotonic loading till fracture and (2) monotonic loading to a predefined strain level, keeping constant displacement for a period of time, and then unloaded. Crosshead speeds of 0.01, 1, and 100 mm/min were used in both series of tests. Likewise, two series of finite element simulation were conducted to establish the constitutive equations, either with or without considering damage evolution during the deformation process. The constitutive equation without the consideration of damage was established using results from the first series of experimental testing, and that with damage was inspired from the second series which showed the decrease in unloading modulus with the increase of crosshead speed or the predefined strain level. The results show that with the consideration of damage evolution, the constitutive equations enable the finite element simulation to determine the whole stress–strain relationship during both necking and fracture processes.


2006 ◽  
Vol 324-325 ◽  
pp. 827-830
Author(s):  
Cheng Yi ◽  
Shi Zhao Shen ◽  
He Ping Xie ◽  
Chang Jun Wang

Partially High Percentage Fiber Reinforced Concrete (PHPFRC) is a kind of cement composite in which fibers are concentrated with high volume fraction in the tension region of the component under bending. Therefore, PHPFRC possesses much higher load bearing capacity, rigidity, fatigue and fracture properties than conventional steel fiber reinforced concrete (SFRC) while its cost is similar to that of SFRC. In this paper, the fatigue test of PHPFRC is carried out to gain its flexural fatigue damage evolution rule. It is found from the test that, PHPFRC have long post-crack fatigue life and its fatigue damage is tough damage. Based on the continuum damage mechanics and fatigue behavior of the specimens, a fatigue damage variable D for PHPFRC is defined and the elementary form of damage evolution function is determined. For the specimens in which average fiber volume fraction are 1.2% and local fiber volume fraction are 10%, the function parameters and the damage threshold value are given according to the test results.


2005 ◽  
Vol 127 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Abı´lio M. P. De Jesus ◽  
Alfredo S. Ribeiro ◽  
Anto´nio A. Fernandes

In this paper, a fatigue model formulated in the framework of the continuum damage mechanics (CDM) is presented. The model is based on an explicit definition of fatigue damage and introduces a kinematic damage differential equation formulated directly as a function of the number of cycles and the stress cycle parameters. The model is initially presented for uniaxial problems, which facilitates the identification of its constants. An extension of the fatigue model to multiaxial problems is also proposed. This model was implemented in a nonlinear finite element code in conjunction with a constitutive model for cyclic plasticity. The cyclic plasticity model considered is based on a J2-plasticity theory with nonlinear isotropic and kinematic hardenings. In order to enhance the description of the cyclic elastoplastic behavior, the superposition of several nonlinear kinematic hardening variables is suggested. Both fatigue and plasticity models are identified for the P355NL1 (TStE355) steel. Finally, the numerical model is used to predict the fatigue crack initiation for a welded nozzle-to-plate connection, made of P355NL1 steel, and results are compared with experimental fatigue data.


2014 ◽  
Vol 904 ◽  
pp. 508-512
Author(s):  
Hong Wang ◽  
Ping Yang ◽  
Jun Lin Deng ◽  
Qin Dong

Based on the continuum damage mechanics theory, according to the development of the fatigue damage evolution equation, and combining the interaction coefficient of stiffener and plate, with plastic strain as the control quantity of damage evolution, the stiffened plate low cycle fatigue damage mechanics model is established, and the calculation method of the fatigue crack initiation life is obtained. This method for the initiation life of fatigue crack is divided into the life before the damage and the life of the damage evolution. The model results are compared with those of the finite element results. Conclusions show that the model can reflect the regularity of axial plastic strain evolution of stiffened plate, and can be directly used for fatigue loads analysis under the mechanism of initiation life.


2014 ◽  
Vol 711 ◽  
pp. 40-43 ◽  
Author(s):  
Yong Qi Wang ◽  
Hai Bing Zhang

The low cycle fatigue damage of turbine disc which is made of GH901 material is systematic analyzed and studied in the article that is based on the theory of continuum damage mechanics and fatigue testing, we improved the common Lemaitre’s low cycle fatigue damage mechanics model, the damage evolution law that the model describes is in good agreement with the test results throughout the course of the fatigue damage. The simplified analysis method for low cycle fatigue damage evolution and life prediction is proposed based on the GH901 low cycle damage features, the practical method of getting damaged material’s constants by existing data is proposed as well.


2017 ◽  
Vol 27 (8) ◽  
pp. 1192-1212 ◽  
Author(s):  
Ding Zhaodong ◽  
Li Jie

The fatigue problem of concrete is still a challenging topic in the researches and applications of concrete engineering. This paper aims to develop a fatigue damage evolution law based model for concrete motivated by the analysis of physical mechanism. In this model, the fatigue energy dissipation process at microscale is investigated with rate process theory. The concept of self-similarity is employed to bridge the scale gap between microscale cracking and mesoscale dissipative element. With the stochastic fracture model, the crack avalanches and macro-crack nucleation processes from mesoscale to macroscale are simulated to obtain the behaviors of macroscope damage evolution of concrete. In conjunction with continuum damage mechanics framework, the fatigue damage constitutive model for concrete is then proposed. Numerical simulations are carried out to verify the model, revealing that the proposed model accommodates well with physical mechanism of fatigue damage evolution of concrete whereby the fatigue life of concrete structures under different stress ranges can be predicted.


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