This thesis provides a detailed field analysis of a specially designed axial-flow radial-flux permanent magnet motor for cooling fan applications. By implementing an iron strip segment at the stator base, this motor can provide a stable guidance force in its axial direction, such that the operational vibration effects can be minimized and the undesired forces applied onto associated bearing system can be alleviated. Supported by adaptive magnetic equivalent circuit and three-dimensional finite element analyses, the motor operational fluxes and forces can be analyzed. Results show that excellent performance and enhanced reliability objectives can all be achieved.

Assembling of the compliant parts used in aviation industry is a challenging process. Assembly fixtures are quite important tools in this effort and widely used in industry. In fixturing of easily deformable sheet metal parts, besides restraining the rigid body motion of the parts, the possible deformations that may occur during the assembly process and the spring-back effect on the final product need to be taken in to consideration. In order to guarantee a successful assembling, in other words, to obtain the final product within specified tolerances, a systematic approach to the fixture design problem is required. The designer should predict the correlation between the input variations and the final assembly variation, especially, for the complex assemblies. This study proposes a design and analysis approach in fixturing of sheet metal assemblies for helicopter components. The design of an assembly fixture for a particular tail cone has been completed convenient to the existing locating principles. Finite Element Analysis (FEA) has been realized in simulating the assembling process in order to predict the possible variation of the interested feature on a complex assembly due to deformations.

During the last years, biomechaniccs, the understanding of the very complex mechanical behavior of living tissue, becomes a very important field of research of the wide bravch of mechanichs. Thia study is very important, for instance , to improve the design of implants, with the important social and economical impact. one of important challenges in implant design is to model the complex material behavior of the bone. Remodeling of the bone due to the lodaing is one of the essential behaviors of the bone which can cause for the dental implants, marginal bone loss accuring particallary in the first years of function. On the other hand the finite element method(FEM) has become the most extended tool for engineers to analyse the mechanical behavior of the products which usualy have a complex material behavior and complicated geometries. The aim of this study is to model the remodeling behavior of the bone using FEM and to use the new bone material method to evaluate the implant performance for some commercial implants, taking account of the bone adaptation.

In this thesis aeroelastic analysis of a typical Unmanned Aerial Vehicle (UAV) using MSC&reg / FlightLoads and Dynamics module and MSC&reg / NASTRAN Aero 1 solver was performed. The analyses were carried out at sea level, 1000m, 2000m and 4000m altitudes for Mach Numbers M=0.2, 0.4 and 0.6 for the full model of the UAV. The flutter characteristics of the UAV for different flight conditions were obtained and presented. The effect of altitude on flutter characteristics has been examined and compared with the theoretical and experimental trends in the literature. Also the divergence characteristics of the full model UAV was obtained. In the study, some verification and test cases are also included. The results of the analyses of an untapered swept-wing and AGARD 445.6 wing models were compared with wind tunnel data and a maximum error of 1.3 % in the flutter speed prediction was obtained. In two different wing models the effect of taper was investigated.

This study mainly covers the finite element analysis of a micro satellite structure by considering the vibration effects at the time interval from the launching to the Earth&rsquo / s orbit landing. Micro-satellites have a great importance in the satellite industry and several developing countries deal with micro-satellite design and production. Turkey is one of these countries by conducting new satellite projects. RASAT project is one the continuing micro-satellite project, which has being developed by T&Uuml / BiTAK Space Technologies Research Institute. In this thesis, the RASAT satellite is taken as the model for the study. On this model, many mechanical design studies which are performed according to the specified requirements and constraints are verified by finite element analyses. These analyses cover all the essential vibration loads during launching. In the study, firstly, a finite element model of RASAT is prepared. Then, the essential analyses are performed according to the specifications required by the launchers. In the analyses, commercially available finite element software is used. Finally all the results obtained from the finite element analyses are compared with the predefined requirements and constraints. The results show that the structural design verification regarding the reliability of the structure for the desired mission has been successfully completed.

The aim of this study is to perform the shape optimization of the lower chassis of the wheeled excavator. A computer program is designed to generate parametric Finite Element Analysis (FEA) of the structure by using the commercial program, MSC. Marc-Mentat. The model parameters are generated in the Microsoft Excel platform and the analysis data is collected by the Python based computer codes. The previously developed software Smart Designer [5], which performs the shape optimization of an excavator boom by using genetic algorithm, is modified and embedded in the designed program.

The objective of the present work is to investigate the behavior of laminated fiber -reinforced polymer matrix composite shell structures under bending load with the help of a modified finite element computer code which was previously developed for the analysis of pseudo-layered single material shells. The laminates are assumed to be orthotropic and the formulation is adapted to first order shear deformation theory. The aim is to determine the large deformation characteristics numerically, and to predict the modes of failure by the illustration of the critical elements of the model. Therefore, several failure theories are also integrated to the code to detect first ply failure. Triangular shell elements are used and all the related data are generated from the mid-plane. Laminates under transverse loading are analyzed through several boundary conditions and ply orientations. To verify the numerical results obtained, a commercial finite element program is used to compare the outputs of the study, and the comparison is found to have shown good agreement. The onset of damage is investigated by using different failure criteria consisting of maximum stress, Tsai-Wu, and Tsai- Hill theories and close results are obtained.

Aluminum based alloys have wide area of usage in automotive and defense industry and bending processes are frequently applied during production. One of the most important design criteria of bending processes is springback, which can be basically defined as elastic recovery of the part during unloading. To overcome this problem, heat treatment is generally applied to the workpiece material to refine tensile properties. In this study, the effect of heat treatment on springback characteristics of aluminum studied both numerically by using finite element analysis and experimentally. For this purpose, two different materials are selected and various heat treatment procedures are considered. The aluminum sheets having thickness of 1.6 mm, 2 mm and 2.5 mm are bent to 60&amp / #730 / , 90&amp / #730 / and 120&amp / #730 / . The von Mises stress distributions, plastic strain values and punch load values and comparison of the numerical and experimental results are also given.

In this study, the settlement behavior of the piled raft foundations resting on overconsolidated clays under uniform loading, is investigated for different pile configurations and load levels. A total of 100 plane &ndash / strain and three &ndash / dimensional finite element analyses are carried out and the results of these analyses are compared both with each other and with the results presented by Reul &amp / Randolph (2004). The material parameters used in the analysis are selected mainly referring to the previous studies cited above on the same subject and slight modifications are made for convenience in the analysis. The analysis method and the applied pile configurations and load levels are directly taken from the reference study, excluding the soil model employed. A drained Mohr &ndash / Coulomb failure criteria is employed in the analysis of this study in modeling the soil instead of an elastoplastic model which was used in the analysis of the reference study. The results are evaluated for the average and differential settlements of the foundations and it is seen that / although the average and differential settlements calculated in this study are not always very close to the values calculated in the reference study, the calculated settlement reduction factors due to piles (especially for the average settlements) compared well with the findings of the reference study for all pile configurations and load levels considered. Based on this, a new approach is suggested to estimate the average settlements of the piled raft foundations. Moreover, correction factors are recommended in order to estimate the average settlements of the piled rafts by directly using the programs employed throughout the thesis.

In this study, equipment rack structure for a medium transport aircraft was designed and finite element analysis of this design was performed. The equipment rack structure, which was designed for a modernization project, was positioned and dimensions were determined by regarding the geometry of primary structures of the aircraft. The structure was designed such that it satisfies the pre-defined margin of safety values. Design of the structure was prepared in Unigraphics, and the finite element modeling and analysis phases were carried out using MSC.Patran and MSC.Nastran programs. For the fastener analysis, which is usually carried out by hand calculations, two analysis tools were prepared by using FORTRAN and Microsoft Office Excel programs. These tools were found to greatly facilitate the analysis and save time. As these tools can be used in other finite element analyses, in which MSC.Patran and MSC.Nastran programs are used, user manuals were prepared.