the present paper is devoted to a new critical state based plasticity model able to predict drained and undrained behaviour of granular material. it incorporates a bounding surface plasticity model describing in multilaminate framework to capitalize on advantages of this mathematical framework. most of the models developed using stress/strain invariants are not capable of identifying the parame...

In this paper, a discontinuity in beams whose intensity is adjusted by the spring stiffness factor is modeled using a torsional spring. Adapting two analyses in strong and weak forms for discontinuous beams, the improved governing differential equations and the modified stiffness matrix are derived respectively. In the strong form, two different solution methods have been presented to make an a...

A COMMON APPROACH used in formulating elastoplastic constitutive equations is to partition the total strain rate into its elastic and plastic parts, and then develop the constitutive expression for the plastic strain rate using the concept of the yield surFace in stress space. An alternative approach is to partition the stress rate into its elastic and plastic parts, and then develop the consti...

In this paper, natural frequencies and dynamic response of thick beams made of saturated porous materials resting on viscoelastic foundation are investigated for the first time. The beam is modeled using higher-order beam theory. Kelvin-voight model is used to model the viscoelastic foundation. Distribution of porosity along the thickness is considered in two different patterns, which are symme...

Results of electro-thermo-elastic analysis of a functionally graded thick-walled spherical shell made of temperature dependent materials are presented in this article. All material properties are assumed temperature-dependent and also are graded along the thickness direction based on power function. Temperature dependency is accounted for all material properties including, thermal, mechanical a...

A plasticity-fracture constitutive model is presented for prediction of the behavior of confined plain concrete. A three-parameter yield surface is used to define the elastic limit. Volumetric plastic strain is defined as hardening parameter, which together with a nonlinear plastic potential forms a non-associated flow rule. The use of non-associated flow rule improves the prediction of the dil...

In this paper a constitutive model formulated in the framework of multi-laminate models is applied to analyze pipe-jacking processes. The multi-laminate -based models consider various integration planes to formulate the stress-strain relationship. This basic feature of the framework has the advantage that yield criteria, flow and hardening rules are formulated on planes rather than in three-dim...

A method for the homogenization of a layered elastic composite is presented. It allows direct, consistent, and accurate evaluation of the averaged overall frequency-dependent dynamic material constitutive relations without the need for a point-wise solution of the field equations. When the spatial variation of the field variables is restricted by Bloch-form (Floquet-form) periodicity, then thes...