Sharif Digital Repository

Fractures of the shaft of the long bones-especially in femur and tibia- is one of the most common fractures. In past decades various methods have been suggested for induction, fixation and repair of these fractures. The main fixation method for shaft fractures of femur and tibia in adult patients is named “Intramedullary Nailing”. In this method, after inducing the fracture, the bone marrow is pulled out via a hole created in the proximal part of the bone. Then, a nail will go down through this empty space inside the bone. This nail will be fixed in to proximal and distal parts of fractures with some locking screws. This way, the part of fracture cannot move respect to each other and the... 

Structures that change shapes are often called morphing structures. Smart morphing composites refer to the morphing structures that can detect the change in conditions and, through a control mechanism, command the actuators to maintain the stability and/or perform a new task. The present report provides a framework on the eld of smart morphing composite structures. The emphasis on this work is on, particularly, multi-stable composite structures with capability to detect the new conditions and adapt themselves to properly respond to them. Due to cycling nature of applied load on morphing, these structures are vulnerable to failure due to fatigue. A failure control mechanism utilizing a... 

Investigation of particles (bubbles or droplets) behavior in two phase flow is widely studied in many chemical engineering processes. This thesis describes CFD simulation for study of dispersed droplets behavior in two phase flow. For this purpose, in population balance equation which is coupled with mass balance equation, Lou and Svendsen model is used for breakage and Prince and Blanch model for coalescence with Eulerian-Eulerian approach for multiphase flow, in conjunction with turbulence model. Then the effect of gas velocity on the coalescence and break up phenomena studied and the results obtained here showed that by increasing gas flow rate, which increased , leads to increase... 

In this project the goal is to study where, when and how the cracks in the steel connection plate between beam and column initiate and how far would the crack grow before failure and how to detect crack initiation by utilizing piezoelectric sensors. In this analysis piezoelectric is placed in line of crack propagation for sensing strain and changing it to voltage. A thin plate with edge notch which is an ideal model of typical beam to column connection is assumed. The plate is subjected to a uniaxial uniform load. With the aid of ANSYS software, the plate is analyzed in both elastic and plastic stages. The strain-stress curve with kinematic hardening part is considered and modeled with... 

Study of fluid flow through the porous fractured media is used in many branches of science such as oil production, environment, water resources, geotechnics and mining, and the results of these researches are useful for industries.The porous fractured media consist of two main parts each having different roles. The first is the fracture networks that act as channels to conduct the fluid in the media, and the second is the porous media that act as a storage space for the fluid. The differences of dimensions and ability of fluid conduction between these two parts would cause the flow analysis to be performed in a heterogeneous and non-isotropic media. Moreover, the irregular networks of... 

Whenever and wherever there is shipping, there exist risks of marine accidents. Subsequently, such accidents at sea may result in potential economic loss,environmental pollution and fatalities. In fact, ship grounding accident is a type of marine accident that involves the impact of a ship on seabed or waterway side. It may result in the damage of the submerged part of the ship’s hull and in particularly the bottom structure; potentially leading to water ingress, which may at the end compromise the ship's structural integrity, stability, and finally safety. An overall view on groundings categorizes the accidents in two major groups: Soft Grounding and Hard Grounding. A soft grounding does... 

The principle of micromechanics has been used to determine the maximum allowable press-fit for the hip stem during total hip arthroplasty. A 2D parametric solution has been presented. Bone and stem cross sections are modeled parametrically with respect to their geometry and mechanical properties. Surrounding soft tissue is also modeled and all the participating materials are considered as linear isotropic. Drucker-Prager fracture criterion is used to interpret the fracture phenomenon which is considered as both strain- and stress-state fracture. Considering presence of a thin layer of cancellous bone in the model caused a significant increase in results in comparison with previous numerical... 

In this thesis, elliptical liquid jet breakup in crossflow has been investigated. To do this, two elliptical nozzle with different aspect ratio were built. First, the effective and important dimensionless numbers were extracted. Then, the physical aspect of the question was analyzed. All the experiments have been done in atmospheric conditions with water fluid, air as the liquid jet, and gas crossflow respectively.To create crossflow, a square cross section channel and one blower which are set in the beginning of the channel were made use of. Water is injected into air crossflow by the injector installed under the channel. The system used in revealing the crossflow is shadowgraphy system.... 

The primary goal of this thesis is to develop a Fault Tolerant Control (FTC) system for a flexible satellite in presence of actuators fault and failure. The actuators of the satellite are including three magnetorquers and three reaction wheels on each principal axis. At first, the three-degree-of-freedom rotational motion of a rigid satellite with two flexible solar panels is modeled. The flexible panels are modeled through the assumed mode approach by a finite set of bending modal motion. The ordinary differential equations of their generalized coordinates are found using the Lagrange’s equation. Then, the dynamic model is validated by comparing the simulation results of the model to the NX...