NEHRP Clearinghouse
- Title
- Nonlinear Hyperelastic (Green) Constitutive Models for Soils. Part I: Theory and Calibration. Part II: Predictions and Comparisons.
- File
- PB81120032.pdf
- Author(s)
- Saleeb, A. F.; Chen, W. F.
- Source
- National Science Foundation, Washington, DC. Engineering and Applied Science., July 1980, 75 p.
- Identifying Number(s)
- CE-STR-80-9
- Abstract
- Three formulation methods for elasticity based stress-strain relations for soils are reviewed. A non-linear hyperelastic constitutive model is described and applied to three types of soils--clays 'X' and 'Y' and Ottawa sand. A description of the procedure for determining the material constraints in the model has been made. Stress-strain relations for general straight line stress paths and for examples of stress paths in conventional soil tests are given. Incremental forms of constitutive relations, an approximate method of modeling unloading-reloading behavior, and a failure condition are included for general nonlinear finite element analyses. Major conclusions are: (1) The proposed constitutive relations can model many characteristics of soil behavior; (2) Present formulation satisfies mathematical requirements when used for monotonically increasing load conditions; (3) Incremental forms of the model can be implemented easily in finite element codes for general analyses; (4) For the cases studied, the model's results are in general agreement with experimental results; (5) The model behavior for Ottawa sand is sensitive to changes in values of material constants; (6) Best results from the model are generally expected at low stress levels below failure; and (7) The present formulation cannot account for post-failure in strain-softening materials.
- Keywords
- Stress strain diagrams; Clay soils; Finite element analysis; Earthquake engineering; Soil properties; Stress analysis; Elastic properties; Soil mechanics