scholarly journals Evaluation of Energy Absorption of Crashworthy Structure for Railway's Rolling Stock (Numerical Simulation Using Damage-Mechanics Model)

2012 ◽  
Vol 78 (793) ◽  
pp. 1325-1339
Author(s):  
Souta KIMURA ◽  
Toshihiko MOCHIDA ◽  
Takeshi KAWASAKI ◽  
Hideyuki NAKAMURA ◽  
Takashi YAMAGUCHI
Keyword(s):  
Numerical Simulation ◽  
Energy Absorption ◽  
Damage Mechanics ◽  
Rolling Stock ◽  
Mechanics Model

scholarly journals Evaluation of Energy Absorption of Crashworthy Structure for Railway's Rolling Stock (Numerical Simulation Applying Damage-Mechanics Model)

2013 ◽  
Vol 7 (1) ◽  
pp. 102-117 ◽  
Author(s):  
Souta KIMURA ◽  
Toshihiko MOCHIDA ◽  
Takeshi KAWASAKI ◽  
Hideyuki NAKAMURA ◽  
Takashi YAMAGUCHI
Keyword(s):  
Numerical Simulation ◽  
Energy Absorption ◽  
Damage Mechanics ◽  
Rolling Stock ◽  
Mechanics Model

Numerical Evaluation of Energy Absorption of Crashworthy Structure for Railway’s Rolling Stock: Application of Damage Mechanics Model

2011 ◽  
Author(s):  
Souta Kimura ◽  
Toshihiko Mochida ◽  
Takeshi Kawasaki ◽  
Hideyuki Nakamura ◽  
Takashi Yamaguchi
Keyword(s):  
Aluminum Alloys ◽  
Energy Absorption ◽  
Compression Test ◽  
Constitutive Equations ◽  
Damage Mechanics ◽  
Model Simulation ◽  
Rolling Stock ◽  
Static Compression ◽  
Gtn Model ◽  
Von Mises

The energy absorption of a crashworthy structure for railway’s rolling stock was studied experimentally and numerically. A quasi-static compression test was conducted using a full-scale mockup of a crashworthy structure constructed with welded aluminum alloys. To predict the experimental results, a finite element (FE) simulation was conducted in which the Gurson-Tvergaard-Needleman (GTN) model, representing the accumulation of ductile fractures by the nucleation, growth and coalescence of micro-voids, was employed as the constitutive equations of the parent aluminum alloys and welded regions. A simulation employing the Von-Mises yielding model as the constitutive equations was performed as a conventional approach to demonstrate the advantages of the simulation using the GTN model in predicting the energy absorbing ability. The predictions of the GTN model simulation were proved to be in better agreement with the experimental data than those of the simulation based on the Von-Mises model. The relationship between the total energy absorption and the local phenomena observed in the compression test is discussed.

scholarly journals Stress wave propagation in different number of fissured rock mass based on nonlinear analysis

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaoming Lou ◽  
Mingwu Sun ◽  
Jin Yu
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Confining Pressure ◽  
Displacement Discontinuity ◽  
Stress Wave Propagation ◽  
Theoretical Derivation ◽  
Mechanics Model ◽  
Fissured Rock ◽  
Deep Rock ◽  
Theoretical Accuracy

AbstractThe fissures are ubiquitous in deep rock masses, and they are prone to instability and failure under dynamic loads. In order to study the propagation attenuation of dynamic stress waves in rock mass with different number of fractures under confining pressure, nonlinear theoretical analysis, indoor model test and numerical simulation are used respectively. The theoretical derivation is based on displacement discontinuity method and nonlinear fissure mechanics model named BB model. Using ABAQUS software to establish a numerical model to verify theoretical accuracy, and indoor model tests were carried out too. The research shows that the stress attenuation coefficient decreases with the increase of the number of fissures. The numerical simulation results and experimental results are basically consistent with the theoretical values, which verifies the rationality of the propagation equation.

Modelling the asymmetric tension–compression properties of additively manufactured alloys using continuum damage mechanics

2021 ◽  
pp. 146442072110134
Author(s):  
A Nayebi ◽  
H Rokhgireh ◽  
M Araghi ◽  
M Mohammadi
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Element Model ◽  
Continuum Damage ◽  
Compression Tests ◽  
Compression Properties ◽  
Mechanics Model ◽  
Stress Components ◽  
Tension And Compression ◽  
Closure Effect

Additively manufactured parts often comprise internal porosities due to the manufacturing process, which needs to be considered in modelling their mechanical behaviour. It was experimentally shown that additively manufactured parts’ tensile and compressive mechanical properties are different for various metallic alloys. In this study, isotropic continuum damage mechanics is used to model additively manufactured alloys’ tension and compression behaviours. Compressive stress components can shrink discontinuities present in additively manufactured alloys. Therefore, the crack closure effect was employed to describe different behaviours during uniaxial tension and compression tests. A finite element model embedded in an ABAQUS’s UMAT format was developed to account for the isotropic continuum damage mechanics model. The numerical results of tension and compression tests were compared with experimental observations for additively manufactured maraging steel, AlSi10Mg and Ti-6Al-4V. Stress–strain curves in tension and compression of these alloys were obtained using the continuum damage mechanics model and compared well with the experimental results.

Modelling and numerical simulation of thick sheet double slitting process using continuum damage mechanics

2014 ◽  
Vol 23 (8) ◽  
pp. 1150-1167 ◽  
Author(s):  
Yosr Ghozzi ◽  
Carl Labergere ◽  
Khemais Saanouni ◽  
Anthony Parrico
Keyword(s):  
Numerical Simulation ◽  
Constitutive Equations ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Thick Sheet ◽  
Technological Parameters ◽  
Strongly Coupled ◽  
Mixed Hardening ◽  
Elasto Plasticity ◽  
Fully Coupled

This work concerns the modelling and numerical simulation of specific thick sheet cutting process using advanced constitutive equations accounting for elasto-plasticity with mixed hardening fully coupled with isotropic ductile damage. First, the complex kinematics of the different tools is modelled with specific boundary conditions. Second, the fully and strongly coupled constitutive equations are summarized and the associated numerical aspects are shortly presented. An inverse material identification procedure is used to determine the convenient values of the material parameters. Finally, the double slitting process is numerically simulated and the influence of the main technological parameters studied focusing on the cutting forces.

Predicting the wear coefficient and friction coefficient in dry point contact using continuum damage mechanics

2018 ◽  
Vol 233 (3) ◽  
pp. 447-455 ◽  
Author(s):  
Sahar Ghatrehsamani ◽  
Saleh Akbarzadeh
Keyword(s):  
Friction Coefficient ◽  
Damage Mechanics ◽  
Point Contact ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Wear Coefficient ◽  
Mechanics Model ◽  
Pin On Disk ◽  
Disk Test ◽  
The Continuum

Wear coefficient and friction coefficient are two of the key parameters in the performance of any tribo-system. The main purpose of the present research is to use continuum damage mechanics to predict wear coefficient. Thus, a contact model is utilized that can be used to obtain the friction coefficient between the contacting surfaces. By applying this model to the continuum damage mechanics model, the wear coefficient between dry surfaces is predicted. One of the advantages of using this model is that the wear coefficient can be numerically predicted unlike other methods which highly rely on experimental data. In order to verify the results predicted by this model, tests were performed using pin-on-disk test rig for several ST37 samples. The results indicated that the wear coefficient increases with increasing the friction coefficient.

Study on Fractal Elastic Damage Constitutive Law for Concrete Material under Static Load

2011 ◽  
Vol 138-139 ◽  
pp. 1269-1273
Author(s):  
Ming Xie ◽  
Shan Suo Zheng
Keyword(s):  
Fracture Surface ◽  
Damage Mechanics ◽  
Constitutive Law ◽  
Uniaxial Test ◽  
Fractal Characteristic ◽  
Mechanics Model ◽  
Evolution Characteristics ◽  
Mesoscopic Level ◽  
Fractal Characteristics ◽  
Stochastic Properties

The stochastic properties and discreteness of macroscopic property for concrete appear on mechanical property and fracture surface. In consideration of stochastik and discreteness of fracture surface, a class of mesoscopic damage mechanics model of concrete based on spring model, are put forward to understand the real damage evolution characteristics of concrete at the level of constitutional law. A kind of spring-slipper model is introduced to reflect the elastic-plastic damage behavior. It has been confirmed that fracture surface of concrete has self-affine fractal characteristic only on a certain spatial scale, but the actual fracture surface of concrete is a stochastic surface with multi-fractal characteristics. Uniaxial test was operated, combined with the Computerized Tomography test of concrete, to study the evolution of crack surface from mesoscopic level to macroscopic level. Compared with the existing damage constitutive law and experimental results preliminarily, the feasibility of fractal damage constitutive law is verified.

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