Sharif Digital Repository

In this study, a new concrete slab stiffened by concrete pedestals and steel cables is introduced. The slab system is studied by employing both analytical and numerical methods. The steel cables are connected to the edges of slab and the concrete pedestals mounted at the bottom face of slab act as the middle supports of cables. The tension force in the cable and its inclination results in upward forces acting at the bottom face of slab. With the aims of classical theory of thin plates and the superposition technique, the problem of a simply supported rectangular slab stiffened by cables is studied analytically. The obtained results are verified by a numerical modelling implemented in SAP2000... 

A tensile-compression ring is derived from the spoke wheel principle. The wheel is one of the greatest inventions in mankind. The use of the wheel has developed through time. Engineers found out that the use of the spoke wheel as a roof structure provides many benefits. With the spoke wheel principle a lightweight, cost-efficient roof structure can be made. In recent years the spoke wheel principle has also been applied for oval shaped roofs in order to increase the application of the principle. An example is the use of the roof structure for football stadia. The problem is that the spoke wheel principle will only work at full extend when its shape is completely circular. The question rises... 

This research investigates the hydrodynamic interaction of a squat submarine operating behind a ship in various wave and resistance experiments for towing and self-propelling arrangements. A one-tenth scaled captive model of a 0.625 m squat submarine is constructed along with a 1.5 m Fridsma ship to perform 116 unique experiments in a 4×6×400 m3 tank located in a towing tank center. The submarine is a new midget-submersible, of Apam-Napat SMSD type, with an L/D ratio below four. The cable is specified, regarding its weight per unit length, using a scaling method introduced in this research. Wave and resistance tests are performed for various 2D relative lengths and depths at short-distance... 

In this project we plan to propose a mechanism for controlling the profile of vertebra displacment and intera-discal pressure in in-vitro tests. Spineis the one of the most important members of the human musculoskeletal system. Health and stability of the spine help the people to moves on two legs. So any problems with this organ, causing movement problems and pain. For the treatment of spinal diseases, several methods such as surgery, insertion of implants and stabilizing were used. To ensure the accuracy of these methods, laboratory examination is essential. One of the ways to test these interventions, the implementation of in vitro tests on samples obtained from the bodies of the spine.... 

The present thesis follows two aims in the phenomenon of vibration and control of cable of cable-stayed bridge under rain-wind induced vibration (RWIV). The first one is to study the response of the cable and consequently the second one aims to control these vibrations that occurred in the cable. The assumed continuous cable has lateral, in plane bending (IP), out of plane bending (OOP) and torsion mode. The effect of rainfall on the cable has been modeled with mobile upper rivulet on the cable surface and the effect and shape of lower rivulet have been neglected. RWIV is not vortex-induced vibration (VIV), nor wake galloping, because the dominant frequency of RWIV is lower than VIV and... 

Quadrotors are one of the most popular unmanned aerial vehicle (UAVs) that has been subject of extensive research in recent years. One of the most important applications of these aerial vehicles is transporting a cable-suspended payload from one point to another. The major challenge in modeling of this system is dynamic coupling which exist between all components of the system i.e. payload, cable and quadrotor. The purpose of this research is mathematical modeling and dynamic analysis of the system in presence of this dynamic coupling and considering the effects of cable's flexibility. In this regard, it is assumed that the payload has variable mass. In this thesis, in the first step, by... 

Today, as an effective tool for marine applications, towed submarines play an im-portant role in various sectors of the marine industry, including defense, recreation, ocean exploration, etc. The high cost of existing thrust systems, as well as the signifi-cant vibrations in them, run counter to the goal of designing this small, low-cost sub-marine. Therefore, the decision was made to design this vessel with a tensile thrust system. In this project, an attempt is made to introduce and design the structure of the body and the carrying capacity of the passenger by a recreational submarine with the ability to move 10 people as passengers And while introducing the structure of the body shape and... 

Although the moment frame can show deformable behavior against seismic loads, but its flexibility and low stiffness, especially in tall structures, cause the governance criterion to be designed. The use of eccentrically braced frames was able to solve the displacement problem to some extent, because it has the characteristics of both flexural frame systems and conccentric bracing. Different methods have been proposed to eliminate residual displacements in this type of system, one of which is the use of post tensioned cables. The aim of this study was to investigate the seismic behavior of a steel structure with a eccentrically braced frame system with post tension cable.The cables are anchor... 

In this research, the dynamic model of a quadrotor-cable airborne wind energy system is presented. These systems have received a lot of attention in recent years and many examples of them have been designed and built. In addition to comprehensive system modeling, cables and quadrotor in the quasi-stable autorotation phase are modeled separately. These models can be used in other fields in addition to wind energy systems. One of the applications of this thick cable model is in the marine industry.In this research, Newton-Euler method has been used for modeling. The cable model is considered and developed as rigid elements with joints with rotary springs and dampers. The quadrotor model is... 

The severe wildfires in California, Australia, Canada, and Iran have interrupted the power system operation, caused multiple blackouts, took many lives, and caused damages to power grid infrastructure to the extent of millions and billions of dollars. Most of the recent wildfires occur in the distribution system. Therefore, enhancing power system distribution resilience against wildfire is crucial.To this end, two groups of measures are proposed: the hardening of the power network and the operational measures. The past published papers mainly studied the resilience enhancement strategies against wildfire from an operational perspective. There is a considerable gap between the past works... 

Conventional eccentric braced frames often sustain large residual deformations and significant damages after strong earthquakes which may lead to heavy damages or even destruction of the structure. Here, a self-centering, Y-inverted, eccentrically braced frame (SC-YEBF) is proposed which combines the lateral load resisting benefits of YEBF including strength, stiffness and energy dissipation capacity with the re-centering capacity of post-tensioned (PT) high strength steel strands used at beam-to-column connections. A design procedure is presented assuming that all the seismic input energy is dissipated through inherent damping and plastic deformations of the link-beams. Thus, in the...