4/25/2021 0 Comments Abaqus Fatigue
It includes leading and industry proven software, such as Abaqus, fe -safe, Tosca, Isight, Simpack, CST, XFlow, and others.Its high accuracy, robustness, and performance are combined with easy to use pre and post processor.
We use cookies to operate this website, improve its usability, personalize your experience, and track visits. By continuing to use this site, you are consenting to the use of cookies. You have the possibility to manage parameters and choose whether to accept certain cookies while on the site. ![]() According to ( 3 ), is a constant matrix in the increment step of damage parameter. Anthymidis Received 15 Nov 2015 Revised 17 Jan 2016 Accepted 20 Jan 2016 Published 16 Feb 2016 Abstract Based on the assumption of quasibrittle failure under high-cycle fatigue for the metal material, the damage constitutive equation and the modified damage evolution equation are obtained with continuum damage mechanics. Then, finite element method (FEM) is used to describe the failure process of metal material. The increment of specimens life and damage state can be researched using damage mechanics-FEM. Finally, the lifetime of the specimen is got at the given stress level. The damage mechanics-FEM is inserted into ABAQUS with subroutine USDFLD and the Python language is used to simulate the fatigue process of titanium alloy specimens. The simulation results have a good agreement with the testing results under constant amplitude loading, which proves the accuracy of the method. Introduction Fatigue failure, as one of the major causes of damage for the mechanical components, relates to alternative loads subjected on engineering structures, which drew increasingly researching work focusing on the fatigue life prediction. There are two methods to forecast the structure fatigue life: one is fatigue safe life prediction based on fatigue cumulative damage theories and the other is damage tolerance method based on fracture mechanics 1. In general, the fatigue life of material is estimated based on the damage tolerance method. However, a high proportion of the overall lifetime for the metal high-cycle fatigue is the fatigue initiation life 2. Damage mechanics is the theory studying the mechanisms and rules of solid material degradation performance by changing mechanical variables under the external loads. As an important branch of damage mechanics, the continuum damage mechanics 3 5 is a theory based on continuum mechanics and irreversible thermodynamics. Abaqus Fatigue Crack Initiation AndTherefore, the process of fatigue crack initiation and development can be analyzed by the fatigue life prediction model based on continuum damage mechanics. And the model of fatigue damage can be classified briefly into ductile fatigue damage model 6 and brittle fatigue damage model 7, 8. Considering that the metal subjected to high-cycle fatigue could be regarded as quasibrittle material, the brittle damage mechanism is often employed to build a damage propagation model on the basis of irreversible thermodynamics 8, which is broadly accepted in engineering practices on account of less parameters of evolution equations. Moreover, the damage numerical analysis method is another core element of damage mechanics. The determination of damage field and the forecast of fatigue life have been achieved by the damage mechanics-finite element method 9 11, which can be utilized to obtain the lifetime of damage initiation and damage propagation path. In this study, a brittle fatigue damage model is modified and combined with a damage constitutive model to predict the fatigue life of the metal material in Section 2. The method to estimate fatigue lifetime of titanium alloy components is accomplished by the commercial software ABAQUS which is developed by programming in Python and Fortran in Section 3. Then, the correctness of the fatigue damage model, the finite element model, and the simulation method is validated through comparing the analytical results with experimental results under constant amplitude loading in Section 4. ![]() Thus, for one-dimensional structure, damage variable 3, 12 can be defined as where is the total area of the cross section and is the total area of microcracks and cavities. Since Lemaitre 4 has obtained the true stress of material by the strain equivalence theory after damage initiation, the constitutive relation of material can be defined, under the state of one-dimensional stress, as where,, and are, respectively, the true stress of damaged material, the initial elasticity modulus of material, and the elastic strain. The constitutive relation of three-dimensional isotropic damage material can be written as where means the material is undamaged and means the material has completely failed. Here, a damage evolution model 8, 13 is introduced as where and are both material constants, is the maximum equivalent stress of loading (MISES), and is the minimum equivalent stress. To obtain the stress and damage field of the model numerically, the nonlinear equations above are solved with the damage parameter as the increment variable.
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