Sharif Digital Repository

The dependence of undrained behavior of silty sand on initial state of stress and direction of principal stresses with respect to vertical (ff) is assessed under generalized loading paths using hollow cylinder apparatus. During applying shear load, value of intermediate principal stress parameter (b) is held constant and ff value is increased from zero to the aimed value and held constant. Specimens are consolidated, both, isotropically and anisotropically to evaluate the effect anisotropic consolidation on the behavior of these soils. The wet tamping method was selected to prepare specimen. Shear loading was carried out under strain-controlled condition to capture post-peak strain-softening... 

Retained austenite as a key constituent in final microstructure plays an important role in TRansformation Induced Plasticity (TRIP) steels. The volume fraction, carbon concentration, size, and morphology of this phase are the well-known parameters which effects on the rate of transformation of retained austenite to martensite and the properties of steel, are studied by many researchers. Of the transformation of retained austenite to martensite under strain in a TRIP steel is studied in this paper. The experimental results show that the transformation rate of retained, austenite with similar characteristics, to martensite in differently processed TRIP steel samples, exhibits an anisotropic... 

Performance-based design (PBD) has become increasingly important in recent years, especially for the design of foundations rested on sub-soils that are susceptible to liquefaction at seismically active areas. Shallow foundations may fail due to excessive settlement because of liquefaction of the underlying loose saturated cohesion-less sands. Building codes usually do not address the issue of liquefaction-induced settlement of shallow foundations. In this paper, a framework is proposed for calculating the liquefaction-induced settlement of shallow foundations resting on heterogeneous two-layered liquefiable soil by conducting a series of 3D. hydro-mechanical dynamic analyses in a fully... 

In this paper, the mechanical properties of graphene oxide are obtained using the molecular dynamics analysis, including the ultimate stress, Young modulus, shear modulus and elastic constants, and the results are compared with those of pristine graphene. It is observed that the increase of oxide agents (–O) and (–OH) leads to the increase of C–C bond length at each hexagonal lattice and as a result, alter the mechanical properties of the graphene sheet. It is shown that the elasticity modulus and ultimate tensile strength of graphene oxides (–O) and (–OH) decrease significantly causing the failure behavior of graphene sheet changes from the brittle to ductile. The results of shear loading... 

Geotechnical design may be unsafe if the anisotropic behavior of soil is not considered. The behavior of anisotropic materials depends on the principal stresses and their directions. A detailed experimental programme was conducted to study the e ect of stress direction on the monotonic and cyclic behavior of dense sand. A total of 20 undrained tests were performed at a constant mean con ning stress (00m), a constant intermediate principal stress ratio (b = (2 - 3)=(1 -3)), and principal stress directions (). Two ne sands, Babolsar and Toyoura, were selected as the test materials. The isotropically consolidated specimens were prepared by the wet tamping technique. The results showed that the... 

In order to evaluate the separation efficiency and flow field of deoiling hydrocyclones a three dimensional simulation is performed using large eddy simulation (LES) approach. Although this approach has been used in other types of hydrocyclones, the present work is a primer application of the LES approach for simulation of deoiling hydrocyclones. Due to anisotropic behavior of flow inside the hydrocyclones, LES is a suitable method to predict the flow field since it resolves large scales and models isotropic small scales. Obtained velocity field using the LES approach in comparison with other turbulence models is in good agreement with available experimental velocity measurements. The method... 

In the present work tensile and tear properties of commercially pure titanium with different rolling reductions and specimens directions were investigated. The experimental results showed that in low levels of deformation the microstructure refining and mechanical twins have fewer significant effects on the anisotropic behavior of both tear and tensile properties and the crystallographic texture controls the mechanical properties anisotropy. The increase in rolling reduction up to 50% led to the formation of strong-basal texture and resulted in the activation of almost same deformation systems and isotropic mechanical response. However, at high levels of deformation, due to the split... 

Consider a steel-rust-concrete composite consisting of a circular cylindrical concrete cover and a coaxial uniformly corroding steel reinforcement. Prediction of the amount of rust penetrated into the microcracks of concrete cover from a set of data measured at the surface of the concrete is of particular interest. The steel is assumed to be linear isotropic and rust follows a power law stress-strain relation. For the concrete, anisotropic behavior and post-cracking softening model is employed. The formulations lead to a nonlinear boundary value problem which is solved analytically. A key parameter β, defined as the ratio of the volume of corrosion products inside the cracks to the volume of...