An explicit integration algorithm for the unified rate-dependent elastoplastic damage model applied to high-rate dynamics

2021 ◽  
Vol 26 ◽  
pp. 102086
Author(s):  
Ruiyuan Huang ◽  
Yi Li
Keyword(s):  
Damage Model ◽  
High Rate ◽  
Explicit Integration ◽  
Integration Algorithm ◽  
Rate Dependent ◽  
Explicit Integration Algorithm ◽  
Elastoplastic Damage

scholarly journals Stability Analysis of an Explicit Integration Algorithm with 3D Viscoelastic Artificial Boundary Elements

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Shutao Li ◽  
Jingbo Liu ◽  
Xin Bao ◽  
Yifan Jia ◽  
Lan Xiao ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Near Field ◽  
Boundary Elements ◽  
Artificial Boundary ◽  
Explicit Integration ◽  
Integration Algorithm ◽  
Explicit Algorithm ◽  
Time Increment ◽  
The Stability ◽  
Explicit Integration Algorithm

Viscoelastic artificial boundary elements are one of the most commonly used artificial boundaries when solving dynamic soil-structure interactions or near-field wave propagation problems. However, due to the lack of clear and practical stability criteria for the explicit algorithm that considers the influence of viscoelastic artificial boundary elements, the determination of the stable time increment in such numerical analyses is still a challenge. In this study, we proposed a numerical stability analysis method for the explicit algorithm with a 3D viscoelastic artificial boundary element based on the idea of a subsystem. Through this method, the artificial boundary subsystem that controls the stability of the overall numerical system is determined, and the analytical solution for the stability condition of the explicit integration algorithm with 3D viscoelastic artificial boundary elements is obtained. On this basis, the maximum time increment for solving dynamic problems with viscoelastic artificial boundary elements can be determined.

scholarly journals Experimental Investigation and Micromechanical Modeling of Elastoplastic Damage Behavior of Sandstone

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3414
Author(s):  
Chaojun Jia ◽  
Qiang Zhang ◽  
Susheng Wang
Keyword(s):  
Damage Evolution ◽  
Triaxial Compression ◽  
Damage Model ◽  
Confining Pressure ◽  
Micromechanical Modeling ◽  
Compression Tests ◽  
Integration Algorithm ◽  
Damage Behavior ◽  
Plastic Strain Increment ◽  
Elastoplastic Damage

The mechanical behavior of the sandstone at the dam site is important to the stability of the hydropower station to be built in Southwest China. A series of triaxial compression tests under different confining pressures were conducted in the laboratory. The critical stresses were determined and the relationship between the critical stress and confining pressure were analyzed. The Young’s modulus increases non-linearly with the confining pressure while the plastic strain increment Nϕ and the dilation angle ϕ showed a negative response. Scanning electron microscope (SEM) tests showed that the failure of the sandstone under compression is a coupled process of crack growth and frictional sliding. Based on the experimental results, a coupled elastoplastic damage model was proposed within the irreversible thermodynamic framework. The plastic deformation and damage evolution were described by using the micromechanical homogenization method. The plastic flow is inherently driven by the damage evolution. Furthermore, a numerical integration algorithm was developed to simulate the coupled elastoplastic damage behavior of sandstone. The main inelastic properties of the sandstone were well captured. The model will be implemented into the finite element method (FEM) to estimate the excavation damaged zones (EDZs) which can provide a reference for the design and construction of such a huge hydropower project.

scholarly journals Theory and Implementation of a Two-Step Unconditionally Stable Explicit Integration Algorithm for Vibration Analysis of Structures

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Li Changqing ◽  
Jie Junping ◽  
Jiang Lizhong ◽  
T. Y. Yang
Keyword(s):  
Vibration Analysis ◽  
Time History ◽  
Superior Performance ◽  
Explicit Integration ◽  
Third Order ◽  
Integration Algorithm ◽  
Unconditionally Stable ◽  
History Analysis ◽  
Integration Algorithms ◽  
Explicit Integration Algorithm

Time history analysis is becoming the routine process to quantify the response of the structure under dynamic loads. In this paper, a novel two-step unconditionally stable explicit integration algorithm, named Unconditional Stable Two-Step Explicit Displacement Method (USTEDM), is proposed for vibration analysis of structure. USTEDM is unconditionally stable, requires low memory, produces no overshoot, and is third order accurate. The accuracy and efficiency of USTEDM are presented and compared with other commonly used integration algorithms. The result shows that the proposed algorithm has superior performance and can be used efficiently in solving vibration response of civil engineering structure.

scholarly journals A Time-Domain Explicit Integration Algorithm for Fast Overvoltage Computation of High-Voltage Transmission Line

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Lei Zhang ◽  
Zhongyi Xu ◽  
Jing Ye
Keyword(s):  
Transmission Line ◽  
High Voltage ◽  
Transmission Lines ◽  
Multiple Time ◽  
Explicit Integration ◽  
Time Step ◽  
Integration Algorithm ◽  
High Voltage Transmission Line ◽  
High Voltage Transmission ◽  
Explicit Integration Algorithm

This paper presents a multiple time-step solver based on a time-domain explicit integration algorithm for improving the computational speed of high-voltage transmission line electromagnetic transient (EMT) simulation. For weakly rigid EMT models of high-voltage transmission lines, the previous precise Runge-Kutta integration method with a small time step is adopted; for strongly rigid nonlinear EMT models of high-voltage transmission lines, a an improved precise integration method using a large time step is used for the solver of EMT simulation. Practical simulations for overvoltages of high-voltage transmission line show that multiple time-step EMT solver can be applied to different cases of EMT simulation for transmission line.

scholarly journals A Coupled Elastoplastic Damage Model for Clayey Rock and Its Numerical Implementation and Validation

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Shanpo Jia ◽  
Zhenyun Zhao ◽  
Guojun Wu ◽  
Bisheng Wu ◽  
Caoxuan Wen
Keyword(s):  
Damage Model ◽  
Clayey Rock ◽  
Triaxial Tests ◽  
Numerical Implementation ◽  
Integration Algorithm ◽  
Stress Criterion ◽  
Proposed Model ◽  
Maximal Tensile Stress ◽  
Nonlinear Hardening ◽  
Elastoplastic Damage

This paper presents a new constitutive model for describing the strain-hardening and strain-softening behaviors of clayey rock. As the conventional Mohr-Coulomb (CMC) criterion has its limitation in the tensile shear region, a modified Mohr-Coulomb (MMC) criterion is proposed for clayey rock by considering the maximal tensile stress criterion. Based on the results of triaxial tests, a coupled elastoplastic damage (EPD) model, in which the elastic and plastic damage laws are introduced to describe the nonlinear hardening and softening behaviors, respectively, is developed so as to fully describe the mechanical behavior of clayey rock. Starting from the implicit Euler integration algorithm, the stress-strain constitutive relationships and their numerical formulations are deduced for finite element implementation in the commercial package ABAQUS where a user-defined material subroutine (UMAT) is provided for clayey rock. Finally, the proposed model is used to simulate the triaxial tests and the results validate the proposed model and numerical implementation.

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