In this research, an approach is developed to automate the design for sheet metal parts that are not only novel and manufacturable but also satisfies multiple objective functions such as material cost. Unlike commercial software tools such as Pro/SHEETMETAL which aids the user in finalizing and determining the sequence of manufacturing operations for a specified component, our approach starts with spatial constraints in order to create the component geometries and helps the designer design. While there is an enormous set of parts that can feasibly be generated with sheet metal, it is difficult to define this space systematically. To solve this problem, we currently have 108 design rules that have been developed for five basic sheet metal operations: slitting, notching, shearing, punching and bending. The technique revealed here represents candidate solutions as a graph of nodes and arcs where each node is a rectangular patch of sheet metal, and modifications are progressively made to the sheet to maintain the parts manufacturability. They are presented in the form of Standard Tessellation Language files (.stl) that can be transferred into available modeling software for further analysis. The overall purpose of this research is to provide creative designs to the designer granting him/her a new perspective and to check all the solutions for manufacturability in the early stage of design process. The abovementioned automation approach uses a new topological optimization technique to solve graph based engineering design problems by decoupling parameters and topology changes. This technique namely Topological and Parametric Tune and Prune (TP²) is the first topology optimization method that has been developed specifically for domains representable by a graph grammar schema. The method is stochastic and incorporates distinct phases for modifying the topologies and modifying parameters stored within topologies. Thus far, with the problems that been tested, (TP²) had proven better than genetic algorithm in terms of the quality of solutions and time taken to acquire them. / text

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This creative project will culminate in a show of twenty-five pieces of metalwork, both wearable and sculptural, using as source material the rich tradition the floral imagery found in Islamic arts. Specifically the pieces will be based on the art of the Persian Gulf area. sources will be floral images as expressed in architectural elements, fabric, tiles, and other related arts or crafts. / Department of Art

This thesis is an analysis of the decoration of a collection of metalwork artefacts excavated in Jordan, dating to the Early Islamic Period (661-900). I have compiled a catalogue of these metal objects which contains a through visual description of each item. These objects have then been organized into three groups of study: animate decoration, inanimate decoration, and the Mafraq brazier. The animate section contains animal and human forms; the inanimate is comprised of vegetal, architectonic, geometric, and epigraphic elements; and the Mafraq brazier is analysed alone due to its complex combination of decoration. Through the analysis of this catalogue of metalwork, I have shown that in the Early Islamic period the Umayyads were utilizing the existing forms of decoration common in the Late Antique period in new combinations and context which resulted in new meanings. This thesis also shows that it is likely that Christian, particularly Coptic, artisans were producing objects for the new Islamic elite.

Face milling machinability investigation of two difficult-to-machine nickel-based superalloys, namely Inconel 718 and Waspaloy, has been carried out with four different types of tungsten carbide tools under various cutting conditions. The tools comprised of one double-layer CVD-TiCN+Al2O3 coated (KC994M), two PVD-TiN coated (KC720 and KC730) and one uncoated (KMF) tungsten carbide tools. The objectives of the study include investigation of tool performance, failure modes and wear mechanisms under the cutting conditions employed. In addition, surface integrity of the machined surfaces, with regard to surface finish, subsurface microhardness and metallographic examination of the subsurface microstructure, was investigated. CVD-coated KC994M gave the best overall performance in terms of tool life at low and high cutting conditions on both workpieces. The second best-performing tool was the uncoated KMF grade which gave as high tool lives as KC994M at lower cutting speeds. However at higher cutting speeds, KMF was generally outperformed by PVD-TiN coated tools. Short tool lives were obtained at higher cutting speeds of 75 and 100 m/min due to premature failure by chipping. Tool wear at low cutting speed range was due to a combination of progressive microchipping and plucking through a fracture/attrition related wear mechanism associated with cyclic workpiece adhesion and detachment and abrasion/diffusion-related flank wear. Plucking and microchipping were the dominant wear mechanisms. Coating layers on the rake face of both CVD and PVD coated tools were almost completely removed within the first few seconds of cutting at all cutting speeds tested, thus becoming ineffective. On the flank face, however, they remained intact for a longer period and hence increasing tools performance at the medium cutting speed range. Analysis of the subsurface microstructures and microhardness measurements showed that plastic deformation was the predominant effect induced onto the machined surface, the degree of which influenced by the cutting speed, tool wear and prolonged machining. In addition surface irregularities in the form of tearing and embedded hard particles were found to occur which was mainly associated with the chipping dominated wear mode.

The motivation behind this study is the lack of specialized analysis regarding internal failure caused by the adiabatic shear hand (ASB) phenomenon in the cold-headed products. Its aim was to present an integrated workability study to improve and assist cold-heading (CH) multistage design procedures to replace the current design rules of thumb, as they are neither effective nor adequate in fulfilling the needs of the new developments in the rapidly expanding CH industry. / To achieve these goals, a comprehensive testing methodology and FE modeling, implemented within ABAQUS/Explicit, were established. This methodology includes an instrumented Drop Weight Compression Test (DWCT) tower equipped with a guided pocket die-set configuration capable of developing internal failure at different stages of ASBs and integrated metallographic inspection techniques. A validated FE model of the DWCT and guided pocket die-set configuration was a valuable tool in establishing the failure criteria and indicating the workability limits. / A detailed experimental and FE study for the ASB stages in the CH process was introduced to uncover the affect of different parameters controlling the failure mechanisms within the ASBs in the CH process. This study investigated the effect of the thermal, geometric and the material flow softening and hardening mechanisms affecting ASB evolution. Moreover, a detailed metallurgical and FE study of the internal ductile and Transformed Adiabatic Shear Band (TASB) failures caused by the ASB phenomenon in DWCT was conducted. / Three ductile failure criteria were introduced to predict the initiation and location of the internal ductile failure in the ASBs. One TASB failure criteria was introduced to predict the phase transformation to undesirable brittle martensite. These failure criteria were employed to establish integrated workability methodologies to indicate the objective workability limits. / Applying these workability methodologies on multistage CH FE models showed that these methodologies are an efficient tool to predict the damage levels and failure initiation locations within the cold-headed bolts. Moreover, these methodologies were successful in optimizing the die designs in order to reduce damage levels.

During the drilling process, sharp edges of material called burrs are produced and protrude from the original surface. When a through-hole is drilled, burrs form on both the entry and exit surfaces around the hole, requiring expensive deburring operations to be performed in order to meet part specifications. A common hole producing operation in aircraft assembly is drilling holes through multiple sheet metal layers in order to fasten them together. However, at the interface between two layers, burrs form on both the exit of the first layer (termed "skin") and entry of the second layer (termed "frame"). Consequently, the layers frequently need to be taken apart, deburred, and put back together again before being fastened, resulting in additional costs and increased assembly time. The goal of this thesis was to understand the role of key factors such as drill geometry, drill wear and clamping conditions on burr formation at the interface of two thin sheets of 2024-T3 aluminum so that interlayer burr formation could be minimized. This problem was approached from three different angles. First, an experimental study was performed to find the drill geometry parameters for minimization of interlayer burrs and to ascertain the relationship between the average burr size and drill wear. Next, a new kind of clamping system for holding sheet metal layers together during drilling was designed, prototyped, and tested for its effectiveness. Finally, a preliminary analytical model of interlayer burr formation was created in order to better understand the burr formation process in stacked layers of sheet metal and to better understand the effect that each drilling parameter has on the resulting burr size.

Thesis (M.S.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (leaves 96-99).

Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 252-266.