Sharif Digital Repository

The aim of this study is to investigate the effects of nanoclay and rubber particles morphologies on fracture behavior of a lightly cross-linked epoxy. In addition, the role of cavitation resistance of rubber particles on fracture behavior of the nanoclay-rubber-epoxy hybrids was studied. Two types of organoclay and three kinds of rubber modifiers (in micron and nano-size) were incorporated into the epoxy. The results obtained indicate that addition of either intercalated or exfoliated clay increases fracture toughness of the epoxy resin, although the increases in toughness are modest (a 50% increase). The microscopy examinations and the micromechanical models revealed that the... 

Monitoring has a high level of importance in the predicting and controlling of dam behavior. At all large dams, the dam performance can be analyzed through the installation appropriate devices during dam construction, impounding and operation periods. The main purpose of monitoring and instrumenting is to investigate variations and safety of dam on the basis of long-term data observations. This paper is aimed at evaluating the behavior of earth dams from the aspect of deformation and settlement during dam construction, impounding and operation periods. As a case study, dams of Shahr chay & Zola, IRAN, have been studied. For this purpose, the obtained results from modeling, deformation and... 

Drop formation from the tip of a nozzle and its motion in bulk fluid is an interesting and practical process which has widely turned researchers’ attention. Investigation into the governing physics and effective parameters on formation, deformation and motion of a drop increases the efficiency of the related industrial processes. Thus in the present study, in order to simulate this process, full Navier-Stokes equations solved by the Volume of Fluid (VOF) method in an axisymmetric domain using Fluent software as the solver. In this research, the effects of Weber number (the proportion of inertial force to surface tension force) and Ohnesorge number (which refers to the proportion of viscous... 

First atomistic simulation was used to study the deformation and fracture mechanisms of Ni-Si interfaces under tensile and shear loads dependent on the crystal structure of interface zone. Modified embedded atom method (MEAM) potential was utilized for molecular dynamics (MD) modeling. The simulation includes analysis of common neighbors, coordination number, least-square atomic local strain, and radial distribution function. The profound effect of interface crystallography on the tensile and shear deformation is shown. The highest tensile strength is obtained for interfaces with high plane density due to lowest atomic disorder while under shear loading planes with low density exhibit a high... 

With intensified concerns of rising fuel vehicles that reduce fossil fuel globally and also prescript strict rules by standard institutes, vehicle manufacturers try to find a way for reducing the fuel of their products. One these methods use a continuously variable transmission (CVT) instead of manual and automatic gearboxes. Various CVT’s have been proposed in recent year.
One of the proposed systems is traction infinitely variable transmission (TIVT) that is type of traction drive continuously variable transmission and has been presented in 2007. Research on this system showed that average efficiency is about 96% that is high efficiency. Completed research in 2011 showed that despite... 

Polymers not just because of their increasing applications in industry but according to their fundamental role in biological mechanisms, has been a topic of interest among different scientific groups. Chemical structure, acroscopic properties and dynamical behavior of these macromolecules are studied in different ways. An important sub-group of polymers are those which according to their chemical properties, after dissolving, release some ions in water and become charged and called polyelectrolytes. A polyelectrolyte with vital importance in our life is DNA which encodes the genetic instructions used in the development and functioning of all known living organisms. One of the main goals in... 

Deformation induced by deep excavations is one of the most important factors in investigating function of retaining structure constructed in urban areas. Predicting content of deformation induced by deep excavations is a fundamental and important step in designing of retaining structures. A prestressed grouted ground anchor is a structural element installed in soil or rock that is used to transmit an applied tensile load into the ground. In this study, effective factors in deformation induced by deep excavation reinforced by method of anchoring is analyzed by application of numerical study based on finite element method by using PLAXIS software, and results are compared. The seismic... 

In this study, thermo-mechanical behavior of an austenitic stainless steel AISI316L was investigated using mathematical modeling and experimental analysis during warm rolling process. First, the thermo-mechanical analysis was carried out employing the finite element software, Abaqus CAE, to assess temperature, strain, velocity and stress distribution during rolling. Then, rolling operations on 316L austenitic steel were performed under different working conditions while mechanical testing as well as microstructural observations were made on the rolled steels. Using simulation results and practical data, microstructural events and mechanical properties after warm rolling of stainless steel... 

The drop motion in fluid and the mass transfer is one of the most interesting and favorite topics that has attracted the attention of many researchers. Knowing the functions of the factors affecting the deformation and the process of mass transfer and the effects of the addition of the surfactant, improve the efficiency of the related industrial processes.In this regard, the present study examines how the shape and speed of a moving Newtonian drop in a Newtonian fluid, the mass transfer of soluble material from inside the drop to the surrounding fluid and also the study of the effect of surfactant on the dynamics of moving droplet is studied numerically. During the drop movement, the...