Sharif Digital Repository

In this thesis, pull-in of nano/micromirrors under effects of capillary, Casimir and van der Waals (vdW) forces is investigated based on two models. In the first model, only rotation of torsional beams of mirror is considered. In the second model, effect of bending of the torsional beams is also considered. The static behavior of the mirror under capillary, Casimir and vdW loading are also studied using these models. Results show that neglecting bending effect, can lead to considerable overestimation in predicting the pull-in limits of the nano/micromirrors under these forces. Results reveal that the static behavior of the nano/micromirrors under these forces highly depends on the... 

In this study, the interaction between thin plate completely bonded to the transversely isotropic halfspace and a concentrated force applied horizontally (Mindlin-type force) are considered. This problem has been solved analytically. This problem is used as sample for thin solid films and surface coating technology, where the surface of solid is covered by thethin plate for increasing its stiffness. Moreover, this problem is a good sample when homogenous solid is subjected to contact loading and can be seen that mechanical properties of material which is near the solid surface varies; consequently, a two-phase solid is created.Because of the influence of noted inhomogeneity, solid is... 

Process Variation is seen as statistical variations in leakage current and delay of transistors in nano-scale technologies. The amount of process variations increase as the size of transistors decrease by technology scaling such that those effects can be seen in frequency of MPSoC (Multi-Processor System-on-Chip) cores and their leakage power deviation. These variations cause the tasks duration and power consumption fluctuate in different processors in an MPSoC instance. Consequently, some chip instances of the same MPSoC may consume more time and power than their considered limitations. Hence considering the process variation is necessary and required for MPSoC optimization at different... 

In Former research we determinate elastic response of Brazilian Test of transversely Isotropic material . In Bio-mechanic science surveying mechanical properties and modeling biological organ such as bone , tooth and bio-material such as titanium, zirconium with application in joint replacement is very important . One of method to determine properties of bio-material which mostly has transversely Isotropic behavior is Brazilian Test. Also most rocks has transversely Isotropic behavior, so choosing efficient test is so important. In current issue , load apply in limited area and it is also considered friction in area of jaw loading area .By use of displacement potential function ... 

By virtue of a robust and efficient method, the solution of triple and quadruple integral equations which are the keys of various mixed boundary value problems corresponding to half-space and full-space media is addressed. These multiple integral equations are reduced to a well-known Fredholm integral equation of the second kind. In order to write the governing integral equations of the problem, Green’s functions play an important role. Therefore, Green’s functions of homogeneous and non-homogeneous transversely isotropic media in the form of line integrals including Bessel functions are obtained. Three interesting mixed boundary value problems in transversely isotropic materials are... 

This research is concerned with the investigation of forced time–harmonic vertical vibration of a rigid disk embedded in a transversely isotropic full space medium. By properties of integral transform methods, the generalized mixed boundary–value problem is formulated as a set of dual integral equations, which in turn, are reduced to a Fredholm equation of the second kind. The obtained Fredholm integral equation is solved by well-known numerical methods. Selected results for the load distribution on the disk and complex compliance are presented for various ranges of frequency.

 

In this paper, the elastic response of a surface-stiffened transversely isotropic half-space subjected to a surface normal load is addressed. The half-space is reinforced by a Kirchhoff thin plate bonded to its surface. Two different boundary conditions are considered across the plate-half-space interface: (i) the classic approach in which the plate in-plane deformation is neglected by writing the interfacial boundary conditions across the plate mid-plane, and (ii) the refined approach that considers the in-plane deformation of plate due to bending by writing the boundary conditions across the bottom face of plate. By virtue of appropriate displacement potentials, the complete set of elastic... 

In this study, the analytical treatment of an anchor plate buried in a transversely isotropic half-space and subjected to a normal point load is addressed. In reality, the tension face of the anchor plate is detached from the soil and the edges of the detached zone extend to a region greater than the anchor plate area. To simulate this situation, the anchor plate is modeled as a rigid circular disk located in a penny-shaped crack and it is in smooth contact with only single face of the crack. With the aid of an appropriate displacement potential function and Hankel transform, the governing equations of the problem are written as a set of triple integral equations. Employing some mathematical... 

Nowadays, regarding to knowledge progresses in various fields,advanced materials for which have acceptable performance in sensitive and special conditions must be used. Functionally graded materials are advanced multiphase composite materials that are characterized by continues spatial variations in mechanical and thermal properties. Clearly, studying on fracture mechanics of FGMs is important because they are used in igh-tech and sensitive applications.In this research, numerical modeling of fracture mechanics in isotropic/orthotropic/ transversely isotropic FGMs via interaction integral method is performed. Both incompatible and non-equilibrium formulations of interaction integral are... 

In this study the axisymmetric and asymmetric problem of interaction between a transversely isotropic half-space and various rst order shear deformation plate theories including Mindlin, Reissner and Vasil'ev are addressed. In order to improve the accuracy of solution, the surface boundary conditions of the half-space are modied.Moreover, the results compared with the exact solution and the most appropriate result is identied. The displacement Green's functions are obtained for both cases, modied and unmodied boundary conditions which can be expressed in a closed form and a numerically evaluated part. The latter is calculated exploiting Built-in numerical interrelation function of... 

The following dissertation examines the interaction between the free surface of a homogenous transversely isotropic half-space and a rigid circular foundation. The whole system is under a vertical and an inclined point loads applied simultaneously on the foundation and at the specified depth of the medium, respectively. Determination of the Green’s functions for the proposed mixed boundary value problem is of interest. By employment of the boundary conditions, the governing equations are represented in terms of a dual integral equation which are subsequently solved analytically. Furthermore, the exact closed-form expressions of the tilt (rotation and settlement) of the loaded rigid foundation... 

In this research, a homogeneous elastic half-space with transversely isotropic behavior, reinforced by an isotropic thin membrane is investigated under static loading with an analytical approach. The membrane is considered as an infinite plane with a thickness of negligible and buried at the arbitrary depth from the surface of the half-space, also its flexural strength is neglected and only the in-plane stiffness is considered for it. The reinforced half-space is investigated under several concentrated and distributed static loads, which are applied to the surface of the half-space or buried at the depth of the membrane. The membrane is first modeled as a three-dimensional elastic layer and... 

The importance of transversely isotropic and functionally graded materials and also plates in industry necessitates studies on these kinds of structures. This study works on the buckling of simply supported rectangular transversely isotropic FGM plates subjected to in-plane uniaxial or biaxial static loads. For this purpose, discretization method is applied and the aforesaid inhomogeneous plate is divided into arbitrary number of sublayers parametrically (N). With the help of displacement potential functions, coupled different equations for each sublayer are simplified to two uncoupled different equations in terms of the potential functions. These governing equations for transversely...