Thesis submitted in compliance with the requirements for the Master's Degree in Technology: Department of Mechanical Engineering, Durban University of Technology, 2008. / The development of an evolutionary optimisation method and its application to the design of an advanced composite structure is discussed in this study. Composite materials are increasingly being used in various fields, and so optimisation of such structures would be advantageous. From among the various methods available, one particular method, known as Evolutionary Structural Optimisation (ESO), is shown here. ESO is an empirical method, based on the concept of removing and adding material from a structure, in order to create an optimum shape. The objective of the research is to create an ESO method, utilising MSC.Patran/Nastran, to optimise composite structures. The creation of the ESO algorithm is shown, and the results of the development of the ESO algorithm are presented. A tailfin of an aircraft was used as an application example. The aim was to reduce weight and create an optimised design for manufacture. The criterion for the analyses undertaken was stress based. Two models of the tailfin are used to demonstrate the effectiveness of the developed ESO algorithm. The results of this research are presented in the study. / M

The analytical theory of the “passive thermal design of spacecraft" can be divided into two parts. The first part is concerned with the description of the radiant heat transfer to spacecraft external surfaces. The second part is concerned with calculating temperature over a spacecraft when the radiant heat incident, on the spacecraft's wall, is known. The first part, the calculation of the heat incident on a spacecraft's external surfaces, has been investigated in the literature. References one, two, and three are examples of such papers. Unfortunately, the results of auch papers are either numerical or else too specialized to be of general interest for the analytical study of the thermal design of spacecraft. The second part, the calculation of temperatures over a spacecraft when the incident radiant heat is known, is also dealt with in the literature. References four and five are examples of such papers. The heat flow, occurring in the walls of spacecraft, is nonlinear because of thermal radiation and few exact solutions are known. This problem is usually attacked by "linearizing'' the nonlinear term or by directly employing power aeries. The solution of the nonlinear heat equation by the linearization process is valid only for small temperature variations. When temperature differences are large, the linearized solutions do not properly account for the nonlinear radiation terms and series error can result. When power series are employed directly to solve the nonlinear heat flow equation, the labor required to solve the time dependent problem is generally excessive because the elementary functions cannot be used efficiently. In this thesis, the radiant heat transferred to spacecraft is found by the use of Fourier series. The resulting solutions are simple and are valid for spacecraft of very general geometry. Heat transfer calculation which previously required extensive integration on electronic computers can be calculated by the results of this thesis with only trivial labor. Also, the results have the advantage of being well suited for use in the solution of the nonlinear heat transfer equation. The problem of heat flow including nonlinear radiation is also attached in this thesis. The method of solution used is closely related to the well known method of successive approximations and allows solution of nonlinear equations which do not have the classical “Small perturbation parameter.” Also, the method of solution used makes good use of the elementary functions so that time dependent problems can be solved without excessive labor. The problems solved in this thesis includes: the temperature time history of a body at uniform temperature but exposed to periodic radiative heating, the temperature time history of a body having nonuniform temperatures and exposed to periodic radiative heating, and finally the problem of linear heat flow with nonlinear boundary conditions. In each case it is shown how linearized solutions neglect the important results of nonlinear radiation heat transfer. / Master of Science

A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1996. / This research project is an investigation into the effectiveness of an inspect and rework system called dynamic section control which has the purpose of improving the assembly quality of the BMW-3 series manufacturing in the Rosslyn Plant just outside Pretoria in South Africa, The system was introduced into the assembly plant in February 1995 to improve the assembly quality of the vehicles as quickly as possible. The main motivation behind the need for this system was to bring the quality onto the same level as the German plants in order to become recognised in the international network of BMW's manufacturing plants along with the new manufacturing plant in the USA The origins of the dynamic section control system come from the Munich 3-series plant as well as being based on the principles of poka yoke, a quality philosophy devised by the quality expert from Toyota in Japan, Shigeo Shingo, Defects found on the assembly plant's line, identified by the quality auditor and information from the marketing department regarding warranty claims are entered onto a checklist which is used by reworkers in the plant to inspect and make good the defects that have been found. The checklist is updated on a weekly basis, hence its name: dynamic section control. Seven rework stations, in which the dynamic section control reworkers work, have been strategically positioned in the assembly plant which trims the painted bodies it receives from the paint shop, The effectiveness of the system has been measured by analysing the information from the daily audits as well as investigating the trend of vehicles If rving the assembly plant still requiring rework and repairs off-line. The analyses were divided into three distinct periods. The first being approximately 4 months before the introduction of :he dynamic section control system, and the second and third periods after the introduction of the system. The results show that the dynamic section control system have a positive influence in improving the assembly quality of the vehicles, especially reducing the number of recurring defects. The number of defects that have only occurred once in each of the periods has remained reasonably constant indicating that the system has no impact in reducing the random occurrence of "one-off" defects. Another significant finding was. the increase in the number of vehicles requiring Department of Mechanical Engineering, University of the Witwatersrand repair off-line, attributable to the assembly plant, after the vehicle has left the assembly line. This increase is probably the result of an increased quality awareness within the assembly plant, resulting in reworkers identifying an increasing number of defects for repair off-line. Other factors such as clearer identification of production goals, training and development of a proportion of the assembly plant's workers in the German plants lor three weeks, reorganizing of support. staff by installing "the right people in the right place" and reducing the number of model derivatives in the plant have also contributed to the enormous quality improvement achieved. Further development of the. dynamic section control system is recommended by installing a rework station within each team area, and including the actions of dynamic section control in the work content of that team. Currently, the system uses external workers which are not part of individual teams as the current sections overlap team areas. Finally, it is recommended that the work of the dynandc section control reworker be incorporated as a noma! function within the team and be rotated amongst the team members. / AC2017

In January 2005, President Bush announced the Vision for Space Exploration. This vision involved a progressive expansion of human capabilities beyond Low Earth Orbit beginning with a return to the moon no later than 2020. Current design processes utilized to meet this vision employ performance based trade studies to determine the lowest cost, highest reliability solution. The methodology implemented in this dissertation focuses on a concurrent evaluation of the performance, cost, and reliabilities of lunar architectures. This process directly addresses the top level requirements early in the design process and allows the decision maker to evaluate the highest reliability, lowest cost lunar architectures without being distracted by the performance details of the architecture. To achieve this methodology of bringing optimal cost and reliability solutions to the decision maker, parametric performance, cost, and reliability models are created to model each vehicle element. These models were combined using multidisciplinary optimization techniques and response surface equations to create parametric vehicle models which quickly evaluate the performance, reliability, and cost of the vehicles. These parametric models, known as ROSETTA models, combined with a life cycle cost calculator provide the tools necessary to create a lunar architecture simulation. The integration of the tools into an integrated framework that can quickly and accurately evaluate the lunar architectures is presented. This lunar architecture selection tool is verified and validated against the Apollo and ESAS lunar architectures. The results of this lunar architecture selection tool are then combined into a Pareto frontier to guide the decision maker to producing the highest reliability architecture for a given life cycle cost. With this presented methodology, the decision maker can transparently choose a lunar architecture solution based upon the high level design discriminators. This method can achieve significant reductions in life cycle costs (over 40%) keeping the same architecture reliability as a traditional design process. This methodology also allows the decision maker to choose a solution which achieves a significant reduction in failure rate (over 50%) while maintaining the same life cycle costs as the point solution of a traditional design process.

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Sonic boom annoyance is an important technical showstopper for commercial supersonic aircraft operations. It has been proposed that aircraft can be shaped to alleviate sonic boom. Choosing the right aircraft shape reflecting the design requirements is a fundamental and most important step that is usually over simplified in the conceptual stages of design by resorting to a qualitative selection of a baseline configuration based on historical designs and designers perspective. Final aircraft designs are attempted by minor shape modifications to this baseline configuration. This procedure may not yield large improvements in the objectives, especially when the baseline is chosen without a rigorous analysis procedure. Traditional analyses and implementations tend to have a complex algorithmic flow, tight coupling between tools used and computational limitations. Some of these shortcomings are overcome in this study and a diverse mix of tools is seamlessly integrated to provide a simple, yet powerful and automatic procedure for sonic boom minimization. A shape optimization procedure for supersonic aircraft design using better geometry generation and improved analysis tools has been successfully demonstrated. The geometry engine provides dynamic reconfiguration and efficient manipulation of various components to yield unstructured watertight geometries. The architecture supports an assimilation of different components and allows configuration changes to be made quickly and efficiently because changes are localized to each component. It also enables an automatic way to combine linear and non-linear analyses tools. It has been shown in this study that varying atmospheric conditions could have a huge impact on the sonic boom annoyance metrics and a quick way of obtaining probability estimates of relevant metrics was demonstrated. The well-accepted theoretical sonic boom minimization equations are generalized to a new form and the relevant equations are derived to yield increased flexibility in aircraft design process. Optimum aircraft shapes are obtained in the conceptual design stages weighing in various conflicting objectives. The unique shape optimization procedure in conjunction with parallel genetic algorithms improves the computational time of the analysis and allows quick exploration of the vast design space. The salient features of the final designs are explained. Future research recommendations are made.

Weight growth has been a significant factor in nearly every space and launch vehicle development program. In order to account for weight growth, program managers allocate a design margin. However, methods of estimating design margin are not well suited for the task of assigning a design margin for a novel concept. In order to address this problem, a hybrid method of estimating margin is developed. This hybrid method utilizes range estimating, a well-developed method for conducting a bottom-up weight analysis, and a new forecasting technique known as executable morphological analysis. Executable morphological analysis extends morphological analysis in order to extract quantitative information from the morphological field. Specifically, the morphological field is extended by adding attributes (probability and mass impact) to each condition. This extended morphological field is populated with alternate baseline options with corresponding probabilities of occurrence and impact. The overall impact of alternate baseline options can then be estimated by running a Monte Carlo analysis over the extended morphological field. This methodology was applied to two sample problems. First, the historical design changes of the Space Shuttle Orbiter were evaluated utilizing original mass estimates. Additionally, the FAST reference flight system F served as the basis for a complete sample problem; both range estimating and executable morphological analysis were performed utilizing the work breakdown structure created during the conceptual design of this vehicle.

In the modem automotive industry product times to market are being increasingly compressed. In the earthmoving and construction machine industry this is also true with the manufacturer having to respond to new customer requirements quickly and decisively. Virtual prototyping is a vital tool in the vehicle engineer's armoury, allowing a large portion of developmental investigation to be done on the virtual model with the attendant savings in time and cost and allowing often dangerous manoeuvres to be predicted and investigated prior to actual physical prototype testing. The University of Natal BELL Equipment collaborative effort involves the vehicle dynamics modelling and model validation of a BELL Equipment manufactured B40C Articulated Dump Truck (ADT). The modelling was completed using the multibody system (MBS) simulation software package, ADAMS. Initial modelling and simulation results are presented with specific attention paid to the introduction of valid data for compliant joints in the MBS as well as modelling of the tire. The physical testing of the ADT is also presented as well as a discussion of the data acquisition system. Key results from the physical testing of the ADT are also presented and discussed. / Thesis (M.Sc.Eng.)-University of Natal,Durban, 2003.

This thesis contributes to research that informs the design of autonomous vehicles (AVs). It examines interactions among various types of road users, such as pedestrians and drivers, and describes how findings can contribute to the design of AVs. The work was undertaken as part of a research internship at Nissan Research Center-Silicon Valley on the Human Understanding in Design team. Methods included video ethnography “travel-alongs” which captured the experience of travel from the point of view of drivers and pedestrians, analysis of interaction patterns taken from video of intersections, and analysis of road laws. Findings address the implications of what it will mean for AVs to exist as social entities in a world of varied road contexts, and how AVs might navigate the social act of driving on roads they share with a variety of human users. This thesis contributes to an emerging body of research and application on the subject of the AV in the world.