S. A. Sadrnejad

[ 1 ] - Substructure Model for Concrete Behavior Simulation under Cyclic Multiaxial Loading

This paper proposes a framework for the constitutive model based on the semi-micromechanical aspects of plasticity, including damage progress for simulating behavior of concrete under multiaxial loading. This model is aimed to be used in plastic and fracture analysis of both regular and reinforced concrete structures, for the framework of sample plane crack approach. This model uses multilamina...

[ 2 ] - Stress Transfer Modeling in CNT Reinforced Composites using Continuum Mechanics (TECHNICAL NOTE)

Because of the substantial difference in stiffness between matrix and nanotube in CNT composite, the stress transfer between them controls their mechanical properties. This paper investigates the said issue, analytically and numerically, in axial load using representative volume element (RVE). The analytical model was established based on the modified Cox’s shear lag model with the use of some ...

[ 3 ] - A 3d Micro-Plane Model for Shape Memory Alloys

are compared with the experimental results. In these test results the shape memory alloys behavior as: super elasticity under various temperatures, loading rate effects, asymmetry in tension and pressure, various loops of loading and unloading, hydrostatic pressure effects, different proportional tension-shear biaxial loading and unloading, and also deviation from normality due to non-proportio...

[ 4 ] - Inelastic Continuum Modeling of Carbon Nanotube,s Behavior Using Finite Element Method

This paper describes a continuum model for analyzing the inelastic behavior of a single walled carbon nanotube (SWCNT) in different loading conditions. Because of limitations in using molecular dynamics (and other atomic methods) to model the failure load of the SWCNT, continuum mechanics methods are considered in this paper. Based on some experimental and theoretical results, an elasto-plastic...

[ 5 ] - A Multi Plane Model for Natural Anisotropy of Sand

Anisotropy of sand is mainly due to the geometrical arrangement of particles that depends on the orientation of applied load respect to the bedding plane. It is geologically due to micro-fabric created by the arrangement of the particles configured during deposition. Most of the models develop using stress/strain invariants are not capable of identifying this kind of anisotropy. This is mainly ...

[ 6 ] - Hydrodynamics Induced Vibration to Trash Racks (TECHNICAL NOTE)

In conventional power plants trash-racks are provided at the intakes to protect the turbines. In pumped storage plants, the draft tube or tailrace must also have trash-racks to protect the units while pumping. Because the loads believed to cause many failures of trash-racks are dynamic in nature, it is important to understand the dynamic characteristics of trash-rack structures in general and a...

[ 7 ] - A Sub Loading Surface Multilaminate Model for Elastic-Plastic Porous Media

A framework for development of constitutive models based on semi-micromechanical aspects of plasticity is proposed. The resulting of this model for material employed friction type failure criterion, sub-loading surface, and associated flow rule. This model is capable of predicting effects of the rotation of principal stress/strain axes and consequent plastic flow, induced anisotropy of strength...

[ 8 ] - Hydraulic Model Studies of Non-Symmetric Y Branches In Karun I (RESEARCH NOTE)

Power stations with high heads are nowadays almost without exception designed so as to have one pipeline, or a few pipelines, supplying the water to the turbines. The penstocks are connected to a distributor, which has the task of distributing the flow with the lowest possible losses of energy to the individual turbines. The function and location of this section of the plant make it understanda...

[ 9 ] - Constitutive Model for Multi-laminate Induced Anisotropic Double Hardening Elastic-plasticity of Sand

A constitutive multi-laminate based elastic-plastic model developed to be capable of accounting induced anisotropic behavior of granular material such as sand. The fabric feature or grain orientation characteristic effects through medium are considered in a rational way under any complex stress path, including cyclic loading. The salient feature of the developed model is a non-associative on pl...

[ 10 ] - Numerical Solution for Gate Induced Vibration Due to Under Flow Cavitation

Among the many force s to which hydraulic structures are exposed to, the forces induced by cavitation incident are of typical hydrodynamic unknown forces. The aim of this study is to define these forces as coupled fluid-structure interaction under two dynamic effects. The first dynamic effect which incorporates facilities for dealing with cavitation fluid is based on the appearance and bursting...

[ 11 ] - Numerical Solution for Heave of Expansive Soils

A numerical solution for heave prediction is developed within the context theories for both saturated and unsaturated soil behaviors. Basically, lowering the potential level of compressing on a saturated layer will cause heaving due to water absorption. This water absorption is in an opposite way, similar to water dissipation as what happens during unloading in consolidation process. However, i...

[ 12 ] - Multilaminate Elastoplastic Model for Granular Media

A multilaminate based model capable of predicting the behavior of granular material on the basis of sliding mechanisms and elastic behavior of particles is presented. The capability of the model to predict the behavior of sand under arbitrary stress paths is examined. The influences of rotation of the direction of principal stress axes and induced anisotropy are included in a rational way witho...