Fire Response Calculation Based on Damage Mechanics

2013 ◽  
Vol 639-640 ◽  
pp. 1193-1199 ◽  
Author(s):  
Song Hua Tang ◽  
Ying She Luo ◽  
Shui Ping Yin ◽  
Yong Hong Li ◽  
Chao Chen ◽  
...  
Keyword(s):  
Temperature Field ◽  
Heat Conduction ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Concrete Slab ◽  
Failure Process ◽  
Strength Theory ◽  
Fire Response ◽  
Damage Evolution Equation ◽  
Damage And Failure

Damage mechanics is introduced into the fire response calculation of the concrete structure. The damage mechanics equations for fire response calculation are established. They are the damage evolution equation based on “residual strength” theory, heat conduction equations, and elastic mechanical equations. The fire response calculation of a concrete slab under external load and fire is shown. ANSYS is selected for calculating. The temperature field and stress field are obtained, the damage and failure process are described using the technique of killing or activating elements in ANSYS, and the fire resistance of the slab is obtained.

Damage Observation and Analysis of a Rock Brazilian Disc Using High-Speed DIC Method

2011 ◽  
Vol 70 ◽  
pp. 87-92 ◽  
Author(s):  
Shao Peng Ma ◽  
Dong Yan ◽  
Xian Wang ◽  
Yan Yan Cao
Keyword(s):  
Strain Field ◽  
Damage Evolution ◽  
High Speed ◽  
Failure Process ◽  
Tensile Load ◽  
Brazilian Test ◽  
Elastic Model ◽  
Strain Fields ◽  
Brazilian Disc ◽  
Damage And Failure

Observation of damage evolution is of great importance to the understanding of the failure process of rock materials. High-speed DIC system is constructed and used to observe the strain field evolution of the granodiorite disc in Brazilian test. The strain fields at different load levels are analyzed based on the stain abnormality indicator (SAI) which is the ratio of the strain measured in experiment to the strain from theoretical solution in an isotropy and elastic model. SAI could be used to indicate the damage in the specimen. The process of damage and failure of the specimen in Brazilian disc test is quantitatively analyzed and deeply discussed according to the strain fields and the statistics of SAI. Experimental results in this paper show that the failure process of the disc specimen in Brazilian test is not simple crack propagation under tensile load, but a complicated damage evolution procedure.

Damage Analysis of Concrete Subjected to Freeze-Thaw Cycles and Chloride Ion Erosion

2011 ◽  
Vol 488-489 ◽  
pp. 464-467
Author(s):  
Ji Ze Mao ◽  
Zhi Yuan Zhang ◽  
Zong Min Liu ◽  
Chao Sun
Keyword(s):  
Constitutive Equation ◽  
Evolution Equation ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Chloride Ion ◽  
Offshore Structures ◽  
Damage Evolution Equation ◽  
Freeze Thaw ◽  
Concrete Materials ◽  
Ion Erosion

With the development of damage mechanics, many researchers have used it to analyze the constitutive equation of concrete. Since the special environment in the cold marine regions, the offshore structures are common to subject to the comprehensive effects of freeze-thaw action and chloride erosion. This might cause concrete materials degradation and reduce the mechanical performance of concrete seriously. In this paper, based on the analysis and mechanical experiments of concrete materials under the comprehensive effects of freeze-thaw action and chloride ion erosion, the damage evolution equation of concrete elastic modulus along with the freeze-thaw cycles and chloride ion contents was established. The effects of chloride ion were investigated during the process of concrete degradation. According to the damage evolution equation, a new constitutive equation of concrete under freeze-thaw action and chloride erosion was established. And then, by means of the element simulation analysis of concrete beams when subjected to the comprehensive actions, the feasibility and applicability of the equation was examined and discussed. In this equation, both the freeze-thaw action and chloride ion erosion were considered together. It will be more suitable for analyzing the durability of concrete structures in the real cold marine regions. It will also provide some references for concrete constitutive theory.

Numerical Simulation of Gun Bore Damage during Engraving Process of Driving Band

2017 ◽  
Vol 1142 ◽  
pp. 363-366
Author(s):  
He Yang Sun ◽  
Chang Zhi Jia ◽  
Yao Xin He ◽  
Tian Xiao Cui
Keyword(s):  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Firing Process ◽  
Computation Method ◽  
Damage Behavior ◽  
Damage And Failure ◽  
Gun Barrel ◽  
Safety Design ◽  
Microscopic Damage

A Damage mechanics finite element numerical computation method was established based on HLC microscopic damage model to solve the problem of damage, crack initialization and growth inside bore during the firing process. The damage and failure process of the bore surface was simulated numerically during multiple rounds of firing. The law of the barrel material performance changing with the number of firing rounds was analyzed during the engraving process of the driving band and compared with the experimental results. It is proved that HLC microscopic damage model can show the complicate damage behavior and predict the cracking defect, which provides a reference for safety design of the gun barrel.

Study on Damage Evolution Mechanism of Concrete under Uniaxial Tension

2012 ◽  
Vol 238 ◽  
pp. 46-50
Author(s):  
Wei Feng Bai ◽  
Ying Cui ◽  
Qian Wang ◽  
Jun Feng Guan ◽  
Jian Wei Zhang
Keyword(s):  
Uniaxial Tension ◽  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Damage Mechanism ◽  
Deformation Characteristics ◽  
Deformation And Failure ◽  
Damage And Failure ◽  
Basic Parameters ◽  
Fundamental Research

The damage and failure mechanism of quasi-brittle materials is the most fundamental research topic in Damage Mechanics. In this paper, the mesoscopic damage mechanism of concrete under uniaxial tension was discussed. The rupture and yield damage modes in meso-scale were introduced as the two basic parameters to define the damage accumulated variable. The results show that the proposed statistical damage model can accurately predict the whole deformation and failure process of concrete under uniaxial tension, including the two-stage deformation characteristics and the size effect.

Study on Anisotropic Fatigue Damage Model of Metal Component

2011 ◽  
Vol 21 (4) ◽  
pp. 599-620 ◽  
Author(s):  
Zhang Miao ◽  
Meng Qingchun ◽  
Hu Weiping ◽  
Zhang Xing
Keyword(s):  
Fatigue Life ◽  
Damage Evolution ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Evolution Equations ◽  
Prediction Method ◽  
Volume Element ◽  
Fatigue Life Prediction ◽  
Repeated Loading ◽  
Damage Evolution Equation

First of all, the boom–panel model is constructed to describe the anisotropic damage evolution of continuum volume element. The constitutive relation of continuum volume element is represented by damage extent of the booms and panels. Furthermore, based on irreversible thermodynamics, damage evolution equations of boom and panel are constructed. The fatigue life prediction method for smooth specimen under the repeated loading with constant strain amplitude is constructed. By the theory of conservative integral in damage mechanics, the fatigue life prediction method for notched specimen under the repeated loading with constant amplitude is obtained. Using these methods, the material parameters of LC4CS aluminum alloy in the damage evolution equation can be obtained by the mean values of experimental fatigue curves of standard specimens with KT = 1, K T = 3, and K T = 5. The computational results are in accordance with the experiment data.

scholarly journals A Modified Fatigue Damage Model for High-Cycle Fatigue Life Prediction

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Meng Wang ◽  
Qingguo Fei ◽  
Peiwei Zhang
Keyword(s):  
Damage Mechanics ◽  
High Cycle Fatigue ◽  
Failure Process ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Cycle Fatigue ◽  
Damage State ◽  
Damage Evolution Equation ◽  
Metal Material ◽  
Python Language

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 specimen’s 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.

Direct Tensile Performance of UHPCC Element Based on Damage Mechanics

2007 ◽  
Vol 348-349 ◽  
pp. 829-832 ◽  
Author(s):  
Sang Mook Han ◽  
Xiang Guo Wu ◽  
Sung Wook Kim ◽  
Su Tae Kang
Keyword(s):  
Constitutive Relation ◽  
Damage Evolution ◽  
High Performance ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Damage Evolution Equation ◽  
Nonlinear Analytical Model ◽  
Material Constitutive Relation ◽  
Modified Weibull ◽  
Direct Tensile

Direct uniaxial tension test of ultra high performance cementitious composites I shape specimens have been investigated in this paper. A nonlinear analytical model based on continuum damage mechanics is developed to characterize tensile stress-strain constitutive response of UHPCC. Basic governing equations of damage evolution and material constitutive relation are established considering random damage which conforms to a modified Weibull type distribution proposed in this paper. Calculation suggests that Weibull distribution can describe damage evolution of UHPCC and predict the constitutive relation and damage evolution equation.

A new damage-coupled cyclic plastic model for whole-life ratchetting of heat-treated U75V steel

2020 ◽  
Vol 29 (9) ◽  
pp. 1397-1415
Author(s):  
Ziyi Wang ◽  
Xiang Xu ◽  
Li Ding ◽  
Guozheng Kang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Fatigue Failure ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Hysteresis Loops ◽  
Continuum Damage Mechanics ◽  
Damage Evolution Equation ◽  
Plastic Model ◽  
Cyclic Plastic ◽  
Heat Treated ◽  
Proposed Model

In the framework of continuum damage mechanics, a new damage-coupled cyclic plastic model is proposed to describe the nonlinear evolution of whole-life ratchetting and its dependence on the stress level. The characteristic that the damage evolution rate of U75V heat-treated steel decays in the initial load cycles is considered by introducing a modified term into classic damage evolution equation. A hybrid fatigue failure criterion considering both the fatigue and ratchetting strain-induced failures is established based on the fatigue failure rule concluded from experiments. Comparisons between simulated and experimental stress–strain hysteresis loops, ratchetting strains, damage evolutions, and fatigue lives are performed to validate the proposed model.

scholarly journals Anisotropic Elastoplastic Damage Mechanics Method to Predict Fatigue Life of the Structure

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Hualiang Wan ◽  
Qizhi Wang ◽  
Zheng Zhang
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Damage Evolution ◽  
Present Method ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Engineering Application ◽  
Damage Evolution Equation ◽  
Material Parameters ◽  
Elastoplastic Damage

New damage mechanics method is proposed to predict the low-cycle fatigue life of metallic structures under multiaxial loading. The microstructure mechanical model is proposed to simulate anisotropic elastoplastic damage evolution. As the micromodel depends on few material parameters, the present method is very concise and suitable for engineering application. The material parameters in damage evolution equation are determined by fatigue experimental data of standard specimens. By employing further development on the ANSYS platform, the anisotropic elastoplastic damage mechanics-finite element method is developed. The fatigue crack propagation life of satellite structure is predicted using the present method and the computational results comply with the experimental data very well.

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