Sheet metal forming has an important place among metal forming processes. As the usage of sheet metal increases, the fatigue simulation and optimization of these parts become more important. This thesis study examines the change of the fatigue life of a sheet metal part after forming. A sphere-like shape is deep drawn and change in thickness and residual stresses are analyzed. To understand the effect of residual stresses, deep drawn parts with and without residual stress tested against the fatigue failure. In parallel, the forming process is simulated with an implicit finite element method (FEM). The success of forming simulation is discussed in the study. Thickness changes and residual stresses calculated with FEM are included in computer aided fatigue analysis. The effect of thickness changes is examined with the results of FEM analysis. The effectiveness of the whole simulation process is discussed by comparing the outputs of experiments and computational analysis.

This study has been conducted to establish a relation between welding quality and strength in various types of steel. This because specification of quality levels higher or lower than required leads to an increase in manufacturing cost. A procedure has been developed to achieve the above objective. In this procedure EN 25817, EN 288-1 and similar welding and nondestructive testing standards have been taken as a basis. Furthermore, effort has been exerted to ensure that welding is performed in a manner that reflects the actual conditions encountered in the industry to the extent possible. The same principles have been pursued in material selection, and the materials have been selected from the low-carbon manufacturing steel types (St37, St44 and St52) that are frequently used in steel construction, boiler manufacturing and similar manufacturing areas. The welded pieces manufactured in accordance with the established procedure have been tested through radiographic and ultrasonic examination methods to check whether they conformed to the welding quality standards set in the procedure. v Quality levels B and C of the EN 25817 standard have been selected for this study. The sizes of potential defects of quality levels have been defined within this standard. In this study, plates with weld seam that has no defect have been used for Quality level B and plates with weld seam having gas pores in sizes specified in the relevant standard have been used for Quality level C. After this stage, the pieces have been subjected to mechanical tests and their strength values have been identified. Thereby, the association between welding quality and strength has been established, enabling us to specify which strength values can be achieved in specific welding quality levels.

This thesis deals with the design, fabrication and analysis of a novel actuator for a fish-like swimming mini robot. The developed actuator is tested on a mini boat. The actuator relies on a novel piezoelectric ultrasonic motor, developed according to the design requirements of actuator for fish-like swimming mini robots. Developed motor is within the dimensions of 25x6x6 mm in a simple mechanical structure with simple driving circuitry compared to its predecessor. Bidirectional rotation of the motor is transformed to a flapping tail motion for underwater locomotion in a simple mechatronic structure. The simplicity in the motor and actuator enables further development on the miniaturization, improvement on the performances as well as easy and low cost manufacturing. The developed actuator is a candidate to be used in mini swimming robot with fish- like locomotion.

There is a strong need in forging industry to reduce waste of material, improve quality, and reduce cost of forgings. About 30% of the material is wasted during conventional closed-die forging. Therefore, in order to reduce the cost of forged products and to obtain near-net or net shape parts, new forging methods should be applied. Precision forging concept is a cost-effective way to produce net-shape or near-net shape components. In recent years, there has been an increased interest in the production of gears by the net-shape forging technique. This has specific advantages over the traditional manufacturing processes of cutting gears such as hobbing, turning, and grinding including savings on cost and raw material, increased productivity, and gears with higher dynamic properties than conventionally cut ones. In this study, precision forging of a particular spur gear has been investigated. The precision forging die set has been conceptually designed and modeled in a computer aided design environment. The forging process of particular spur gear has been simulated by using a commercially available finite volume program. After the successful simulation results, the prototype die set and the tube-shaped billets were manufactured. The real-life experiments have been realized by using 1000 tons mechanical forging press available in METUBILTIR Research and Application Center Forging Laboratory. The results have been compared with the computer simulations. After the real-life experiments, it has been observed that the conceptual die design is appropriate and near-net shape spur gears are successfully obtained by the proposed precision forging die set.

This thesis presents the computer implementation of a multi resolutional concurrent, design inference network, whose nodes are refined by PNDN (Petri Net Based Design Inference Network) modules. The extended design network is named as N-PNDN and consists of several embedded PNDN modules which models the information flow on a functional basis to facilitate the design automation at the conceptual design phase of an engineering design. Information flow in N-PNDN occurs between parent and child PNDN modules in a hierarchical structure and is provided by the token flow between the modules. In this study, computer implementation of the design network construction and token flow algorithms for the N-PNDN structure is restored and therefore the previous DNS (Design Network Simulator) is adapted for the multi layer design and decomposition of mechatronic products. The related algorithms are developed by using an object oriented, visual programming environment. The graphical user interface is also modified. The further developed DNS has been used for the application of the N-PNDN structure in the conceptual design of 5 mechatronic systems. In the guidance of this study, it has been understood that the further developed DNS is a powerful tool for designers coming from different engineering disciplines in order to interchange their ideas.

The main goal of this thesis is the development of a novel methodology to generate creative solutions at functional level for design tasks without binding solution spaces with designers&rsquo / individual experiences and prejudices. For this purpose, an evolutionary methodology for the conceptual design of engineering products has been proposed. This methodology performs evaluation, combination and modification of the existing solutions repetitively to generate new solution alternatives. Therefore, initially a representation scheme, which is generic enough to cover all alternatives in solution domain, has been defined. Following that, the evolutionary operations have been defined and two evaluation metrics have been proposed. Finally, the computer implementation of the developed theory has been performed. The test-runs of developed software resulted in creative alternatives for the design task. Consequently, the evolutionary design methodology presents a systematic design approach for less experienced or inexperienced designers and establishes a base for experienced designers to conceive many other solution alternatives beyond their experiences.

Detta examensarbete omfattar produktutvecklingen av ett multiaxiellt styrt maskinstativ, som senare vid en slutlig produkt skall vara ämnad för användning inom additiv tillverkning. Arbetet som utförts har lett fram till konceptframtagning, materialval och tillverkning av en skalkonstruktion för ett 3-axiellt styrt maskinstativ. Tester och simuleringar har gjorts för att se om maskinkonstruktionen går att använda efter de kravspecifikationer som ställts av värdföretaget. Konstruktionen höll sig väl inom sin tolerans på 100 mikrometer vid rumstemperatur men visade vissa felmarginaler vid arbetstemperaturen på 600 grader Celsius. Resultaten som erhållits har analyserats för att kunna ge vidare förslag på förbättringar av konstruktionen då det ännu kvarstår implikationer vid säkerställandet av toleranserna vid arbetstemperaturen. / This thesis covers the product development of a multi-axial driven machine frame, which at a later stage will be intended to be used in additive manufacturing. The work that has been performed has led to concept development, material selection and manufacturing of a shell construction for a 3-axially driven machine construction. Tests and simulations have been done to verify if the machine design can be used by the specifications set by the host company. The construction was well within its tolerance of 100 microns at room temperature but showed some error margins at the operating temperature of 600 degrees Celsius. The results obtained have been analyzed in order to provide further suggestions for improvement of the structure when there still remain implications in ensuring the tolerances at operating temperature.

In this thesis, design and development and manufacturing processes of an industrial type vacuum sweeper is presented. Thesis is financially supported by Ministry of Industry and Trade-Turkey and M&uuml / san A.S. (Makina &Uuml / retim Sanayi ve Ticaret A.S.) under SAN-TEZ project number 00028.STZ.2007-1. It is aimed to make innovative design changes and developments on the M&uuml / san VSM 060 type vacuum sweeper. To achieve this aim, alternative configuration designs are prepared by using commercial 3D modeling program, Catia&trade / V5. Basic vehicle structure is constructed. New M&uuml / san VSM 060 will be a fully electrically driven vehicle. All subsystems will be activated by using electrical motors whose power is supplied by batteries. All subsystems are mounted on the chassis which is a welded frame structure made up of 60x40x2 St37-2 grade steel tubes. Finite element analysis (FEA) of the chassis is performed by using commercial structural finite element analysis tools MSC Patran pre and post processor and MSC Nastran solver. Moment calculations are done for structural parts. Cleaning system of the new VSM 060 vehicle is decided to be a combination of mechanical and vacuum cleaning systems. An elevator system will be integrated in addition to vacuum system to pick up coarse particles. The vacuum system will mainly be utilized for very small size particle collection. Computational fluid dynamics (CFD) analyses are done by Punto M&uuml / hendislik Ltd. Sti. for the whole cleaning system components by using CFdesign, an upfront CFD analysis tool.

This thesis deals with the structural design of small model CNC milling machines. The work includes research modeller CNC milling machines available primarily on the Czech market, on whose basis are then selected the appropriate parameters for machine design. The thesis contains further structural calculations, selection of appropriate components, production drawings and 3D model that shows the final solution of constructed facility.

The topic of this work is the design of a small model CNC milling machine with a fixed table for machining wood, plastic, or light alloys (Al, Zn, etc.). It also includes a calculation report and drawing documentation of selected nodes. The beginning of this work consists of an introduction to the issue of milling machines, their distribution and subsequent market analysis. Subsequently, the input parameters are designed on the basis of market analysis and in the last part there is a calculation report, the design of the milling machine itself and a short economic evaluation.