scholarly journals Stress-point algorithm for a pressure-sensitive multiple-yield-surface plasticity theory

1982 ◽  
Author(s):  
T Hughes
Keyword(s):  
Yield Surface ◽  
Plasticity Theory ◽  
Surface Plasticity ◽  
Pressure Sensitive ◽  
Stress Point

Isotropic–kinematic hardening model for coarse granular soils capturing particle breakage and cyclic loading under triaxial stress space

2016 ◽  
Vol 53 (4) ◽  
pp. 646-658 ◽  
Author(s):  
Qingsheng Chen ◽  
Buddhima Indraratna ◽  
John P. Carter ◽  
Sanjay Nimbalkar
Keyword(s):  
Cyclic Loading ◽  
Critical State ◽  
Kinematic Hardening ◽  
Plasticity Theory ◽  
Particle Breakage ◽  
Granular Soils ◽  
Stress Space ◽  
Bounding Surface ◽  
Bounding Surface Plasticity ◽  
Surface Plasticity

In this paper, a simple but comprehensive cyclic stress–strain model that incorporates particle breakage for granular soils including ballast and rockfill has been proposed on the basis of bounding surface plasticity theory within a critical state framework. Particle breakage and its effects are captured by a critical state line that is translated in voids ratio–stress space according to the dissipated energy (plastic work), through a hyperbolic function. A comprehensive equation related to particle breakage is proposed for the stress–dilatancy relationship to capture the complex dilatancy of granular soils. By extending Masing’s rule to bounding surface plasticity theory and introducing a generalized homological centre, a combined isotropic–kinematic hardening rule and a mapping rule have been established to simulate more realistically the response of gravelly soils under cyclic loading. The applicability and accuracy of this model are demonstrated by comparing its predictions with experimental results for different types of granular soils, including rockfill, under both monotonic and cyclic loading conditions. This study shows that the model can capture the characteristic features of coarse granular soils under complex loading paths.

scholarly journals Numerical Modeling of Soil-Pile-Interaction with Near and Far Field Earthquake's Effects

2017 ◽  
Vol 3 (5) ◽  
pp. 351-364
Author(s):  
Mohammad Shahmohammadi Mehrjerdi ◽  
Ahmad Ali Fallah ◽  
S.T. Tabatabaei Aghda
Keyword(s):  
Yield Surface ◽  
Direct Method ◽  
Response Spectrum ◽  
Near Field ◽  
Soft Clay ◽  
Structural Response ◽  
Time History ◽  
Far Field ◽  
Plasticity Model ◽  
Surface Plasticity

This paper studies Near and Far Field effects of the response of a column-pile to earthquakes considering Dynamic-Soil-Structure-Interaction (DSSI) effects in soft clay (Vs<180 m/s ) and stiff clay (180<Vs<375 m/s). Opensees software that can simulate the dynamic time history analysis is used. Both kinematic and inertial interactions are considered and Finite Element Method (FEM) is used to solve DSSI. The direct method applies to 3D modeling of the layered soil and column-pile. A Pressure Independ Multi Yield Surface Plasticity Model is used to simulate different kinds of clay behavior.  Time history seismic analyses provide for the mass and stiffness matrices to evaluate dynamic structural response with and without directivity effects for Near and Far Field earthquakes. Results show that the Multi-Yield-Surface-Kinematic-Plasticity-Model can be used instead of bilinear springs between piles and clay soil, for both Near Field and Far Field earthquakes. In addition, comparing Near and Far Field analyses, acceleration response spectrum at the top of the structure in the Far Field increases with the softness of the soil more than that in the Near field.

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