An endochronic damage model for three-dimensional ductile failure analysis of double-edge notched thick-tension specimens

1998 ◽  
Vol 212 (1) ◽  
pp. 25-34
Author(s):  
C L Chow ◽  
X F Chen
Keyword(s):  
Damage Evolution ◽  
Failure Process ◽  
Damage Model ◽  
Three Dimensional ◽  
Ductile Failure ◽  
Failure Criteria ◽  
Ductile Damage ◽  
Damage Evolution Equation ◽  
Double Edge ◽  
Failure Loads

A three-dimensional ductile damage model based on the endochronic plastic theory is developed and employed to characterize the failure process of double-edge notched thick-tension specimens. A ductile damage evolution equation is derived with a new intrinsic time-scale specifically defined to characterize damage evolution. Two damage failure criteria are proposed and employed to predict the failure loads and crack initiation sites which correspond well with those measured experimentally.

scholarly journals Simple Progression Law in Predicting the Damage Onset and Propagation in Composite Notched Laminates

2018 ◽  
Vol 7 (4.26) ◽  
pp. 163
Author(s):  
Mohd Suhairil Meon ◽  
Narasimha Rao Mekala ◽  
Kai-Uwe S Schroeder
Keyword(s):  
Damage Model ◽  
Three Dimensional ◽  
Failure Criteria ◽  
Constitutive Law ◽  
Fiber Reinforced Polymer ◽  
Damage Initiation ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Ultimate Failure ◽  
Progressive Damage Model

The aim of this article is to simulate the damage initiation and progression in unidirectional (UD) laminates. A three-dimensional (3D) failure criteria of Puck incorporated with degradation scheme is developed. Two types of degradation law known as sudden degradation are used to predict the damage progression in UD laminates. The establishment of constitutive law in progressive damage model (PDM) is achieved through implementation of user subroutines in Abaqus. The failure analysis is applied to various composite stacking sequences and geometries, as well as different fiber reinforced polymer (FRP) composite materials. The comparative studies revealed that the predicted ultimate failure load agree well with those available in the literature. 

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.

scholarly journals The Progressive Failure Analysis of Uni-Directional Fibre Reinforced Composite Laminates

2020 ◽  
Vol 36 (2) ◽  
pp. 159-166
Author(s):  
T. Yi
Keyword(s):  
Composite Laminates ◽  
Progressive Failure ◽  
Failure Process ◽  
Damage Model ◽  
Three Dimensional ◽  
Dissipated Energy ◽  
Solid Element ◽  
Reinforced Composite ◽  
Shear Rupture ◽  
Composite Solid

ABSTRACTThe three dimensional standard damage model developed by Lavedeze et.al [9, 13] for uni-directional fibre reinforced ply is implemented into the nonlinear solution of NX Nastran within composite solid element to analyze the progressive damage process and ultimate failure of fibre reinforced composite laminates. This ply level meso-damage-constitutive-model takes into account main damage mechanisms including fibre breaking, matrix transverse cracking, and fibre/matrix de-bonding; also considers contributions like plasticity coupling, damage delay effects, and elastic nonlinearity in fibre compression. Dissipated energy and damage status are also introduced to reflect the damage condition on the macrostructural-level. Using the implemented code, simulation is carried out on the uniaxial tension of a [±45]2s laminate with IM6/914 material, wherein the predicted ply shear rupture stress matches the experimental results very well and better than the theoretical predictions in literature. Moreover, a [-45/0/45/90] holed laminate loaded in tension is simulated to show the complex behavior of subcritical damage evolution and failure process in the composite structure. The composite solid element with damage model supported in NX Nastran is shown to be a reliable tool to analyze the progressive failure of uni-directional fibre reinforced composite laminates.

Progressive Damage Model of FRP Composite Laminates with Central Hole

2011 ◽  
Vol 194-196 ◽  
pp. 1581-1585
Author(s):  
Chong Qiang Sun ◽  
Jian Yu Zhang ◽  
Bin Jun Fei
Keyword(s):  
Composite Laminates ◽  
Failure Process ◽  
Damage Model ◽  
Failure Criteria ◽  
Numerical Results ◽  
Central Hole ◽  
Progressive Damage ◽  
Element Mesh ◽  
Damage Models ◽  
Frp Composite

Progressive damage method is adopted to predict the static mechanics properties of FRP composite laminates with central hole. Progressive damage models with three different 3D failure criteria and material degradation models are established and analyzed via a user defined subroutine embedded into the general FEA package. Numerical results indicate that all the three 3D failure criteria can simulate the failure process of FRP laminates with central hole, but the final failure load is different. Degradation coefficient and the finite element mesh have significant effect on the numerical results.

scholarly journals Particle jet impact deep-rock in rotary drilling: Failure process and lab experiment

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250588
Author(s):  
Tiancheng Fang ◽  
Fushen Ren ◽  
Baojin Wang ◽  
Jianxun Cheng ◽  
Hanxu Liu
Keyword(s):  
Damage Evolution ◽  
Failure Process ◽  
Damage Model ◽  
Engineering Application ◽  
Rock Breaking ◽  
Drilling Speed ◽  
Rotary Drilling ◽  
Rock Stratum ◽  
Technical Problems ◽  
Jet Impact

Aimed at the technical problems of low drilling speed and difficult rock-breaking in deep-well and hard rock-stratum, particle waterjet coupled impact rock-breaking technology in rotary drilling is put forward in this paper. Firstly, the working principle of particle jet impact rock-breaking in rotary drilling was introduced, and the acceleration model of particle jet and the damage model of rock were established. The acceleration mechanism of particles and dynamic damage evolution process of rock under particle jet were studied, which showed that the broken pit and rock damage would increase with time gone on, and damage evolution of rock presented the radial expansion. Then, experimental device of particle jet coupled impact rock-breaking in rotary state was developed, and the effect of jet parameters on penetration depth and failure volume was analyzed with comparison of la experiment and numerical simulation. The results showed that drilling speed with particle jet impact is twice that of conventional drilling, and combination nozzles layout of impact angle with 8°and 20° can achieve rock-drilled rapidly, which also demonstrated the correctness of simulation method. The device development and the rock-breaking results analysis would be of great value for engineering application.

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.

On the Dependency of Ductile Damage Evolution to Stress State with Shock Loading Pre-Mechanical Working in 7075-T6 Aluminum Alloy

2016 ◽  
Vol 08 (04) ◽  
pp. 1650050 ◽  
Author(s):  
Sina Gohari Rad ◽  
Majid Alitavoli ◽  
Asghar Zajkani ◽  
Abolfazl Darvizeh
Keyword(s):  
Aluminum Alloy ◽  
Stress State ◽  
Damage Evolution ◽  
Damage Model ◽  
Evolution Model ◽  
Pressure Effects ◽  
Ductile Damage ◽  
Plastic Behavior ◽  
Special Focus ◽  
Mechanical Working

In this paper, the evolution of a ductile damage in the 7075-T6 aluminum alloy is considered based on stress state parameters with a special focus on pre-mechanical working dependency. Uniaxial stress–strain curves are investigated experimentally for two conditions; specimens with shock loaded pre-mechanical working and without it. This kind of loading is applied in order to find out impulsive pressure effects of damage variation procedure. Some experiments are done to take different stress states. Applying two fracture initiations criteria, i.e., Hosford–Coulomb and Xue models, two types of fracture locus of Al-7075-T6 are predicted in terms of plastic strains and stress state parameters under above conditions. By considering experimental data, a new ductile damage evolution model is proposed among plastic behavior. It is introduced by explicating an uncoupled plasticity and related to initial rate dependent stress state. By using both fracture models, our damage evolution model is implemented, phenomenologically as well as the Xue damage model, to compare results.

Influence of Geometrical Features of Meso-Defects on Damage Evolution of Metal Structure

2015 ◽  
Vol 723 ◽  
pp. 21-25
Author(s):  
Chao Fan Zhao ◽  
Zhao Xia Li
Keyword(s):  
Aspect Ratio ◽  
Damage Evolution ◽  
Structural Damage ◽  
Volume Fraction ◽  
Failure Process ◽  
Damage Model ◽  
Metal Structure ◽  
Geometrical Features ◽  
Gtn Damage Model ◽  
Defect Volume

To study the failure process of metal structure with meso-defects, RVE (representative volume element) with various initial meso-defects were analyzed by using ABAQUS software, the parameter f (void volume fraction) of GTN damage model was regarded as the criterion of structural damage. The result shows that f increased more obvious with volume of defects for spherical defects with the same shape but different size. When the radius of defects is less than 0.15mm, the influence of defects’ volume on increases of f is clear enough. When the radius is greater than 0.15mm, the effects is diminishing. For ellipsoidal defects with the same volume but different aspect ratio, when the long axis perpendicular to the direction of load, the increased trend of f according to plastic deformation more obvious along with aspect ratio of defects. Apparently, as aspect ratio approaches infinity, f would have the fastest growth. Consequently, the bigger defect volume and aspect ratio, the more conducive for damage evolution of the metal structure.

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