Critical state elasto-plastic constitutive models for soil failure in tillage - a review

Karmakar, S., Sharma, J. and Kushwaha, R.L. 2004. Critical state elasto-plastic constitutive models for soil failure in tillage – A Review. Canadian Biosystems Engineering/Le genie des biosystemes au Canada 46: 2.19-2.23. Soils, in general, undergo both elastic and plastic deformations upon loading. A realistic constitutive model of soil behaviour must be able to distinguish between the elastic and plastic deformations. A large number of isotropic elasto-plastic constitutive models have been developed for sand, clay, and rock during the last four decades. These models have been used for analysing tillage tool interaction with soil. To describe the behaviour of soil subjected to a tillage tool with a rather complex loading path, the model should also account for the dependency of certain material properties on the stress history of the soil. In this article, an attempt has been made to review some of these critical state elasto-plastic models with reference to their application in soil-tool interaction. Strain dependant anisotropic elastoplastic models have been found to be a need for realistic modeling for agricultural soil-tool mechanics.