Preliminary Study on Flow Constitutive Model of Post Liquefied Sand in Zero Effective Stress State

2013 ◽  
Author(s):  
G. Zhou ◽  
Y. M. Chen ◽  
H. L. Liu
Keyword(s):  
Stress State ◽  
Constitutive Model ◽  
Effective Stress ◽  
Preliminary Study

scholarly journals Displacement mechanisms of slow-moving landslides in response to changes in porewater pressure and dynamic stress

2019 ◽  
Vol 7 (3) ◽  
pp. 707-722 ◽  
Author(s):  
Jonathan M. Carey ◽  
Chris I. Massey ◽  
Barbara Lyndsell ◽  
David N. Petley
Keyword(s):  
Stress State ◽  
Effective Stress ◽  
Dynamic Stress ◽  
Movement Patterns ◽  
Rate Of Change ◽  
Ground Acceleration ◽  
Deformation Control ◽  
Slow Moving ◽  
Porewater Pressure ◽  
State Component

Abstract. Although slow-moving landslides represent a substantial hazard, their detailed mechanisms are still comparatively poorly understood. We have conducted a suite of innovative laboratory experiments using novel equipment to simulate a range of porewater pressure and dynamic stress scenarios on samples collected from a slow-moving landslide complex in New Zealand. We have sought to understand how changes in porewater pressure and ground acceleration during earthquakes influence the movement patterns of slow-moving landslides. Our experiments show that during periods of elevated porewater pressure, displacement rates are influenced by two components: first an absolute stress state component (normal effective stress state) and second a transient stress state component (the rate of change of normal effective stress). During dynamic shear cycles, displacement rates are controlled by the extent to which the forces operating at the shear surface exceed the stress state at the yield acceleration point. The results indicate that during strong earthquake accelerations, strain will increase rapidly with relatively minor increases in the out-of-balance forces. Similar behaviour is seen for the generation of movement through increased porewater pressures. Our results show how the mechanisms of shear zone deformation control the movement patterns of large slow-moving translational landslides, and how they may be mobilised by strong earthquakes and significant rain events.

CONSTITUTIVE MODEL FOR CONCRETE UNDER BIAXIAL STRESS STATE

1993 ◽  
Vol 4 (4) ◽  
pp. 387-397
Author(s):  
E. J. Stavrakakis, ◽  
C. E. Ignatakis, ◽  
G. G. Penelis,
Keyword(s):  
Stress State ◽  
Constitutive Model ◽  
Biaxial Stress ◽  
Biaxial Stress State

scholarly journals Towards Fracture Prediction in Single Point Incremental Forming

2013 ◽  
Vol 554-557 ◽  
pp. 2355-2362 ◽  
Author(s):  
Carlos Felipe Guzmán ◽  
Anne Marie Habraken
Keyword(s):  
Stress State ◽  
Incremental Forming ◽  
Single Point ◽  
Shell Element ◽  
Single Point Incremental Forming ◽  
Damage Development ◽  
Lode Parameter ◽  
Damage Models ◽  
Preliminary Study ◽  
Rupture Mechanism

The stress state in metal forming processes usually implies low values of triaxiality. It is well known that damage models based only on triaxiality fails to capture the damage behavior properly, and recent articles have stressed the effect of the Lode parameter in describing damage. Moreover, in some process like incremental forming, the through thickness shear could dominate the rupture mechanism making the description, using solely the triaxiality, inaccurate. In this paper, a preliminary study of the stress state is carried over a near-to-failure single point incremental forming (SPIF) formed cone, through finite elements simulations using a newly developed solid-shell element. The results provide a basis for further studies into damage development in SPIF.

scholarly journals A Statistical Damage Constitutive Model for Geomaterials under Plane-Strain Biaxial Stress State

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Hongwei Zhang ◽  
Zhijun Wan ◽  
Chaoyi Wang ◽  
Zhaoyang Ma ◽  
Yuan Zhang ◽  
...  
Keyword(s):  
Stress State ◽  
Constitutive Model ◽  
Mechanical Behavior ◽  
Plane Strain ◽  
Biaxial Stress ◽  
Statistical Parameters ◽  
Biaxial Stress State ◽  
Damage Constitutive Model ◽  
Statistical Damage Constitutive Model ◽  
Statistical Damage

The mechanical behavior of geomaterials under plane-strain biaxial stress state (PSBSS, a special case of biaxial stress state) is often considered in geotechnical structures such as highwall and longwall coal pillars. In this study, a modified statistical damage constitutive model based on Weibull distribution was established to explain the mechanical behavior of rocks under the PSBSS. The modified Wiebols-Cook criterion, Drucker-Prager criterion, and extremum method were adopted in this model to estimate the peak strength of rock, the strength level of microscopic element, and the statistical parameters of model, respectively. Besides, laboratory tests for brittle and ductile geomaterials under PSBSS were conducted using the modified surface instability detection apparatus to validate the accuracy of the proposed statistical damage model. Finally, the relationships between mechanical parameters and statistical parameters were studied and discussed.

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