A New Nonlinear Stress-Strain Model for Soils at Various Strain Levels

2013 ◽  
Vol 631-632 ◽  
pp. 782-788
Author(s):  
Cheng Chen ◽  
Zheng Ming Zhou

Soils have nonlinear stiffness and develops irrecoverable strains even at very small strain levels. Accurate modeling of stress-strain behaviour at various strain levels is very important for predicting the deformation of soils. Some existing stress-strain models are reviewed and evaluated firstly. And then a new simple non-linear stress-strain model is proposed. Four undetermined parameters involved in the proposed model can be obtained through maximum Young’s module, deformation module, and limit deviator stress and linearity index of soils that can be measured from experiment directly or calculated by empirical formulas indirectly. The effectiveness of the proposed stress-strain model is examined by predicting stress-strain curves measured in plane-strain compression test on Toyota sand and undrained triaxial compression test on London clay. The fitting results of the proposed model are in good agreement with experimental data, which verify the effectiveness of the model.

Author(s):  
K. J. Thompson ◽  
R. Park

The stress-strain relationship of Grade 275 steel reinforcing bar under cyclic (reversed) loading is examined using experimental results obtained previously from eleven test specimens to which a variety of axial loading cycles has been applied. A Ramberg-Osgood function is fitted to the experimental stress-strain curves to follow the cyclic stress-strain behaviour after the first load run in the plastic range. The empirical constants in the function are determined by regression analysis and are found to depend mainly on the plastic strain imposed
in the previous loading run. The monotonic stress-strain curve for the steel, with origin of strains suitably adjusted, is assumed to be the envelope curve giving the upper limit of stress. The resulting Ramberg-Osgood expression and envelope is found to give good agreement with the experimentally measured cyclic stress-strain curves.


2005 ◽  
Vol 42 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Ignacio Escuder ◽  
Joaquin Andreu ◽  
Manuel Rechea

The analysis of stress–strain behaviour and the effects of submergence on quarried rock shells, used mainly in dams but also in road construction, is of major importance from both economic and safety points of view. The research work presented here starts with an in-depth review of the nonlinear elastic procedure widely used in rockfill analyses since 1970, its later application to simulate wetting effects, and the latest published modifications to the so-called hyperbolic stress–strain model. An update of the existing wetting simulation procedure has been formulated, calculation routines to analyze constructional behaviour and wetting effects on rockfills have been implemented, and the methodology developed has been applied to a structure 100 m high. Calculation routines have been written to run in FLAC, a finite difference based code that incorporates a programming language. The analyzed structure is part of a road rockfill located at the Contreras Reservoir in Spain and consists specifically of two shell-shaped cross sections subjected to the influence of submergence. The results are expected to be useful in estimating collapse settlements in the upstream shells of earth-core dams.Key words: elasticity, stress–strain, rockfills, behaviour, numerical, dams.


AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 2187-2189
Author(s):  
Marcus C. Johansson ◽  
Jens Knoell ◽  
Dale B. Taulbee

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1078 ◽  
Author(s):  
Yugui Cao ◽  
Muyu Liu ◽  
Yang Zhang ◽  
Jun Hu ◽  
Shengchun Yang

There are many studies on fiber-reinforced polymer (FRP)-confined pre-damaged concrete under quasi-static strain rates. However, few studies have focused on FRP-confined pre-damaged concrete under high strain rates. Thus, an experimental and analytical investigation was conducted to obtain the mechanical behavior of FRP-confined pre-damaged concrete under different strain rates. The results show that the stress–strain curves, ultimate stress, and strain values were affected by strain rate and the extent of concrete damage. A stress–strain model of FRP-confined pre-damaged concrete considering the strain rate was developed by modifying a stress–strain model of FRP-confined pre-damaged concrete under quasi-static loading. The proposed model was evaluated by using test data. The evaluation results show that the proposed model can predict the stress–strain behavior of FRP-confined pre-damaged concrete under different strain rates.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Yongjei Lee ◽  
Yong-Ha Hwang

This study proposes a simple and rational stress-strain relationship model applicable to brick masonry under compression. The brick prism compression tests were conducted with different mortar strengths and with constant brick strength. From the observation of the test results, shape of the stress-strain curve is assumed to be parabola. In developing the stress-strain model, the modulus of elasticity, the strain at peak stress, and the strain at 50% of the peak stress on the descending branch were formulated from regression analysis using test data. Numerical and statistical analyses were then performed to derive equations for the key parameter to determine the slopes at the ascending and descending branches of the stress-strain curve shape. The reliability of the proposed model was examined by comparisons with actual stress-strain curves obtained from the tests and the existing model. The proposed model in this study turned out to be more accurate and easier to handle than previous models so that it is expected to contribute towards the mathematical simplicity of analytical modeling.


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