Sharif Digital Repository

This research evaluates reliability analysis on the problem of a curved beam vibration in the horizontal plane with the aim of investigating the effect of the uncertainty of the parameters of the problem on the dynamic response of the curved beam under the excitation of the moving oscillator. Curved beams are widely used in various engineering applications such as arched bridges, railway tracks and amusement park structures. However, there have been very few studies on curved beams under the stimulation caused by moving mass. Modelling the moving object as a moving oscillator, which is one of the more advanced and complete modelling of the passing vehicle, along with analyzing the... 

This study investigates the dynamics of a two-mass oscillator travelling on a viscoelastic rectangular plate under both accelerating/decelerating and uniform motions, while accounting for surface roughness and various reattachment scenarios. Despite its practical significance, this topic has received limited attention in scholarly literature. The Current article studies how key parameters—including the oscillator’s initial velocity, acceleration, foundation/oscillator damping and stiffness, as well as impact type (elastic, plastic, and elastoplastic)—affect the system’s dynamic response. It also examines, via illustrative examples, the oscillator’s motion along paths parallel and diagonal to... 

The primary objective of this research is to develop a suitable method for solving the out-of-plane vibration equation of spinning disks, and to investigate the system's response probabilistically while analyzing its reliability. Spinning disks have extensive applications in various industries and engineering fields, including computer disk-drive systems, electronic components, and rotating machinery. These disks experience severe vibrations at certain speeds due to resonance phenomena, which affect their performance and may lead to system failure. Initially, this research solves the governing equation of the motion of rotating disks deterministically using an analytical method. A thin air... 

The reinforced concrete deep beam is a structural member with mostly shear behavior that can be seen in various members such as beams of bridges and tall structures, girder beams, and equipment-carrying beams in industrial structures. Due to the non-linearity of the strain in these members, various parameters are important in their behavior and response, including the compressive strength of concrete, the type of loading, the type and amount of shear reinforcement, and the cross-sectional dimensions. Deep beams' ultimate damage and failure are generally shear, brittle, and sudden. Therefore, considering the importance and sensitivity of these crucial structural members, it is necessary to... 

This thesis aims to study the dynamic behavior of circular and annular plates. First, free vibration of the plate, resting on a Pasternak foundation with a variable subgrade modulus, by using the infinite power series method is presented. The proposed method applies to various boundary conditions with no restriction. A comprehensive study is carried out to investigate the effects of the different parameters on the behavior of the plate. The obtained results demonstrate that the Pasternak foundation has a significant influence on the natural frequencies and greatly increases them. Secondly, the dynamic response of thin and moderately thick plates subjected to a moving load is considered. In... 

The Energy Dissipating Restraint (EDR) is a friction device which can be used to dissipate the energy introduced to a structure by a seismic event.A special characteristic of this device is that it is self-centering, which makes it preeminent among other friction dampers. As a result of high nonlinearity associated with the behavior of the EDR, the analysis and performance assessment of the structures which are outfitted with EDR entail quite a few nonlinear time-history analyses. Regarding the substantial computational cost of this method, the existing provisions have authorized the use of more economical alternative methods for the analysis of the structures whose motions are controlled... 

This thesis investigates the dynamic response of a viscoelastic plate resting on a viscoelastic Winkler foundation subjected to the excitation of a moving mass. Through application of the Laplace transform, the governing equation of the problem is derived for a general viscoelastic material. Thereafter, an analytical-numerical method is proposed in order to determine the dynamic response of the viscoelastic plate. The method is based on transforming the governing partial differential equation into a new solvable system of linear ordinary differential equations. To that extent, the proposed solution proves to be applicable to plates made of any viscoelastic material and with various boundary... 

Statistical studies indicate the fact that in Iran, like many other developing countries, a significant percentage of buildings are made of traditional materials and most of them are adobe buildings especially in rural areas. Furthermore, geological data indicates that Iran is located in alps-Himalayas seismic zone and exposed by destructive earthquakes and adobe buildings suffer the most damages comparing with other type of the structures. According to these explanations, this research deals with adobe buildings behavior and provides solutions for reinforcing them and improving the seismic response of these buildings. These studies include numerical modeling with finite elements methods by... 

In this thesis we consider the problem of distributed computation by many processors.We mainly concentrate on matrix multiplication problem in this thesis because of its importance. A distributed system consists of N worker processors and one master processor. The master processor should distribute the computation between workers and after computation in each of them, collect the results. In this thesis, we are going to mitigate the effect of straggler processors by using coding methods. Straggler processors can cause delays in the computation time.In this thesis, we firstly introduce a method to multiply any number of matrices in each other. The proposed method occurred in one shot without... 

The main goal of current investigation was partial reduction of Fe2O3 available in Hematite-rich ore to Magnetite by Fludization Bed method. The reductive gas, CO, was produced by incomplete combustion of Acetylene and Airmixed in inappropriate ratio. X-Ray Diffraction and X-Ray Florescence analyses were implemented in order to conducting qualitative analysis of present phases before and after reduction of the ore. Quantitative analysis of the same phases was also conducted by Titration. The latter analysis revealed the precise magnitude of available iron in each of the oxide containing phases. The chemical composition of the reactor gas was also determined before and after reduction... 

Abstract The problem of competetive facility location can be defined as follows: There are a number of customers in the form of points in space, and two players arrange a number of facilities in the form of points in space, given some limitations, respectively. Each customer’s connection to each facility has a cost for the customer and an advantage for the facility, and each customer wants to be connected to at most one of the facilities which has the lowest cost for him. The goal is to find the strategy of placing the facilities and determining the cost which the facility receives from the customer, in such a way that the player’s profit is maximised.In this thesis, we first sought to... 

Zero knowledge proofs allow a person (prover) to convince another person (verifier) that he has performed a specific computation on a secret data correctly, and has obtained a true answer, without having to disclose the secret data. QAP (Quadratic Arithmetic Program) based zkSNARKs (zero knowledge Succinct Non-interactive Argument of Knowledge) are a type of zero knowledge proof. They have several properties that make them attractive in practice, e.g. verifier's work is very easy. So they are used in many areas such as Blockchain and cloud computing. But yet prover's work in QAP based zkSNARKs is heavy, therefore, it may not be possible for a prover with limited processing resource to run...