Making More Cars with Less Metal

Reducing sheet metal yield losses in automotive manufacturing would reduce material demand, providing environmental and financial benefits. This thesis explores material efficiency from four perspectives: 1. The opportunity for improvement: A part by part analysis of yield losses for every sheet metal component in a vehicle highlights nine material efficiency strategies. An industry study finds that on average only 56% of sheet metal purchased is used on the vehicle. Improving material utilisation to best practice of 70% would save £8 billion and 25 million tonnes of CO2 annually. 2. The potential to realise this opportunity: A design process to improve material efficiency is trialled within an automotive manufacturer and identifies opportunities of 20%. However, only 3% improvement is realised since the material efficiency opportunity is locked in at the start of the design process, where resource is not currently allocated. Earlier consideration of material utilisation is required. 3. Material efficiency within the circular economy: All existing metrics for recycling in sheet metal forming processes are mapped onto a diagram. A case study demonstrates that existing recycling metrics, do not promote the reduction of yield losses. Considering recycling process efficiencies rather than recycled content would enable recycling rates to be measured without penalising material efficiency. 4. Design for material efficiency: There are currently no suitable tools to inform process selection and geometry decisions for material efficiency. To address this, a novel set of experiments is conducted. These experiments identify a trend between the maximum draw depth and three critical radii. This trend could form a geometry based formability guideline which would enable design for material efficiency. Approaching material utilisation from these perspectives gives greater certainty of the saving opportunity for sheet metal material efficiency and clarifies the priority of material efficiency compared to other strategies to meet global climate change goals.Sponsored by Jaguar Land Rove

EXTENDING ORIGAMI TECHNIQUE TO FOLD FORMING OF SHEET METAL PRODUCTS

This dissertation presents a scientific based approach for the analysis of folded sheet metal products. Such analysis initializes the examination in terms of topological exploration using set of graph modeling and traversal algorithms. The geometrical validity and optimization are followed by utilizing boundary representation and overlapping detection during a geometrical analysis stage, in this phase the optimization metrics are established to evaluate the unfolded sheet metal design in terms of its manufacturability and cost parameters, such as nesting efficiency, total welding cost, bend lines orientation, and maximum part extent, which aides in handling purposes. The proposed approach evaluates the design in terms of the stressed-based behavior to indicate initial stress performance by utilizing a structural matrix analysis while developing modification factors for the stiffness matrix to cope with the stress-based differences of the diverse flat pattern designs. The outcome from the stressed-based ranking study is mainly the axial stresses as exerted on each element of folded geometry; this knowledge leads to initial optimizing the flat pattern in terms of its stress-based behavior. Furthermore, the sheet folding can also find application in composites manufacturing. Thus, this dissertation optimizes fiber orientation based on the elasticity theory principles, and the best fiber alignment for a flat pattern is determined under certain stresses along with the peel shear on adhesively bonded edges. This study also explores the implementation of the fold forming process within the automotive production lines. This is done using a tool that adopts Quality Function Deployment (QFD) principle and Analytical Hierarchy Process (AHP) methodology to structure the reasoning logic for design decisions. Moreover, the proposed tool accumulates all the knowledge for specific production line and parts design inside an interactive knowledge base. Thus, the system is knowledge-based oriented and exhibits the ability to address design problems as changes occur to the product or the manufacturing process options. Additionally, this technique offers two knowledge bases; the first holds the production requirements and their correlations to essential process attributes, while the second contains available manufacturing processes options and their characteristics to satisfy the needs to fabricate Body in White (BiW) panels. Lastly, the dissertation showcases the developed tools and mathematics using several case studies to verify the developed system\u27s functionality and merits. The results demonstrate the feasibility of the developed methodology in designing sheet metal products via folding

Allocation of Two Dimensional Parts Using a Shape Reasoning Heuristic.

A technique is outlined for the allocation of irregular parts onto arbitrarily shaped resources. Placements are generated by matching complementary shapes between the unplaced parts and the remaining areas of the stock material. The part and resource profiles are characterized to varying levels of detail using geometric features . Information contained in the features is used at each stage of processing to intelligently select and place parts on the resource. Techniques for the efficient handling of complex profiles and other practical implementation issues are described. The utility of the proposed approach is verified using diverse problems from a marine fabrication facility. The formulation and performance of the method is contrasted to previously published works

VIABILITY OF ADDITIVE MANUFACTURING FOR PRODUCTION AND TOOLING APPLICATIONS: A DEVELOPMENT OF THE BUSINESS CASE

As marketplace competition drives industrial innovation to increase product value and decrease production costs, emerging technologies foster a new era through Industry 4.0. One aspect of the movement, additive manufacturing, or 3D [three-dimensional] printing, contains potential to revolutionize traditional manufacturing techniques and approach to design. However, uncertainties within the processes and high investment costs deter corporations from implementing and developing the technology. While several industries are benefitting from additive manufacturing’s current state, as the technology continues to progress, more companies will need to evaluate it for industrial viability and adoption. As such, there exists a need for a framework to evaluate the business case for investment review. While many papers in the literature provide cost estimation models for additively manufactured parts, there does not exist a thorough guide for decision making. This master’s thesis report introduces a process to evaluate machine investment and part production between additive manufacturing and traditional manufacturing technologies using operational and financial key performance indicators. A case study application of the process yielded suspect part unit costs 3.71% higher than its literature basis, indicating a viable methodology. The present value total investment cost for an EOSINT M 270 machine tool, with a five-year lifespan, was determined to be $3,241,710 in the case context; breakeven point occurs beyond investment life at 2.28 years. Results were dependent on product valuation and assumptions made. Key output metrics indicated the suspect machine could generate 5,238 units annually at a 1.4 part per hour throughput rate. As part production was deemed feasible under the provided constraints, sensitivity analysis indicated material and equipment costs as cost drivers. Similarly, production drivers were found to be scan rate and machine utilization. Results were consistent with common belief that additive manufacturing is currently viable for small-to-mid series production, or parts of high complexity value. These findings indicate areas of improvement for the additive manufacturing industry for commercialization purposes, and demonstrate a useful methodology for assessing the business case of additive manufacturing

A Survey on Array Storage, Query Languages, and Systems

Since scientific investigation is one of the most important providers of massive amounts of ordered data, there is a renewed interest in array data processing in the context of Big Data. To the best of our knowledge, a unified resource that summarizes and analyzes array processing research over its long existence is currently missing. In this survey, we provide a guide for past, present, and future research in array processing. The survey is organized along three main topics. Array storage discusses all the aspects related to array partitioning into chunks. The identification of a reduced set of array operators to form the foundation for an array query language is analyzed across multiple such proposals. Lastly, we survey real systems for array processing. The result is a thorough survey on array data storage and processing that should be consulted by anyone interested in this research topic, independent of experience level. The survey is not complete though. We greatly appreciate pointers towards any work we might have forgotten to mention.Comment: 44 page

Geobase Information System Impacts on Space Image Formats

As Geobase Information Systems increase in number, size and complexity, the format compatability of satellite remote sensing data becomes increasingly more important. Because of the vast and continually increasing quantity of data available from remote sensing systems the utility of these data is increasingly dependent on the degree to which their formats facilitate, or hinder, their incorporation into Geobase Information Systems. To merge satellite data into a geobase system requires that they both have a compatible geographic referencing system. Greater acceptance of satellite data by the user community will be facilitated if the data are in a form which most readily corresponds to existing geobase data structures. The conference addressed a number of specific topics and made recommendations

Impacts of Invasive Phragmites Australis on Diamondback Terrapin Nesting

The diamondback terrapin (Malaclemys terrapin) is a species of turtle found exclusively in brackish water habitats. Terrapins are currently facing population threats including by-catch mortality in crab pots, predation, and habitat loss. The expansion of the exotic, invasive reed Phragmites australis is causing widespread structural and functional changes to coastal ecosystems throughout North America, which could negatively impact the nesting success of female terrapins by invading preferred nesting habitats. I examined the extent to which Phragmites affects nesting of a breeding population of diamondback terrapins at Fisherman Island National Wildlife Refuge on the eastern shore of Virginia, where Phragmites has recently expanded into known areas of terrapin nesting. With data collected from the 2015 nesting season I quantified the impacts of this expansion on terrapin nesting by: determining the extent to which nest incubation temperature is impacted by Phragmites shading, determining how Phragmites density impacts the risk of rhizome invasion into nests, and determining how the presence of Phragmites impacts predation of terrapin nests. I also examined landscape features to determine which factors may be associated with diamondback terrapin nest site use. I found that Phragmites cover greater than 50% would decrease incubation temperatures of terrapin nests sufficiently to produce predominantly male hatchlings. There was no effect of Phragmites cover on root growth into simulated nests, but cover by other dune plant species explained observed trends in root growth. I did not find a significant effect of Phragmites on nest predator activity, but did find that Phragmites had an impact on terrapin nest site use on Fisherman Island. Distance from nest to nearest marsh and tidal creek also influenced terrapin nest site use. With crab pots and roadways contributing to high adult mortality every year, high nesting success will be highly important to maintaining and propagating this charismatic species

Behavioral Responses of Willow Flycatchers, \u3ci\u3eEmpidonax traillii\u3c/i\u3e, to a Heterogeneous Environment

Spatial heterogeneity impacts population and community-level dynamics including species-level dispersal patterns, the use and availability of refugia, predator/prey dynamics, and reproductive fitness. Understanding how wild animal populations respond to environmental heterogeneity is essential for their proper management and conservation. In this study, I examine the responses of Willow Flycatchers to spatial heterogeneity in the distribution of their food and habitat resources. Over the course of three breeding seasons, I radio- tracked Willow Flycatchers at Fish Creek in Manti-La Sal National Forest in Utah, recorded detailed behavior data at each radio location, and collected fecal, feather and insect samples. I formulated individual and population-level Bayesian spatial resource selection functions to model Willow Flycatcher foraging and vocalization behavior on multiple scales. These models indicate that vocalization and foraging behavior are spatially segregated within the home ranges of Willow Flycatchers. Further, Willow Flycatchers were found to use mature riparian habitat for vocalizing while they used a variety of habitat types for foraging. The insect samples were used to identify distinct carbon and nitrogen stable isotope signatures for the aquatic and terrestrial insect communities at Fish Creek. In conjunction with the fecal samples, I used the stable isotope signatures to determine the contribution of aquatic versus terrestrial insects to the Willow Flycatcher diet. Aquatic insects comprised a larger proportion of the diet of adult than nestling Willow Flycatchers. This suggests that adult flycatchers consume a diet that is distinct from the one they feed to their nestlings. Finally, I compared space use characteristics in two populations of Willow Flycatchers: a population of the endangered Southwestern Willow Flycatcher at Roosevelt Lake, Arizona and another belonging to a non-endangered subspecies of Willow Flycatcher at Fish Creek, Utah. Differences in space use were found largely among breeding flycatchers while space use characteristics in non-breeding Willow Flycatchers did not differ across populations. This suggests that space use patterns in non-breeding Southwestern Willow Flycatchers may be generalizable to non-breeding flycatchers from non-endangered populations. This study expands our understanding of how Willow Flycatchers respond to spatial heterogeneity while its key findings have management and conservation implications for the species