M.Ing. (Civil Engineering) / Variable EI, post tensioned continuous bridge decks frequently occur in practice. The design of such a deck is essentially a process of trial and error. The aim of this thesis is to facilitate the design process by eliminating the sting from the otherwise complex flexural analysis by the development of suitable PC programs. This thesis will focus on the following three main issues: 1 SECTION PROPERTIES The program PROP presents a minimum input approach for the determination of uni-axial section properties. Special enP1aSis is placed on the section efficiency factor, being a direct quantitative measure of a sections flexural ability, ranging from 0 to 1. The effect of this factor on partial prestressing is also discussed. 2 THE MAGNEL DIAGRAM The program MAGNEL presents a linear programming optimisation aid for the design of uneracked sections (i.e. Classes 1 and 2 prestressing). The following is catered for: • variable prestress loss • both sagging and hogging moments • composite construction • two stage stressing • secondary moments due to prestressing The effects of the section efficiency factor, area redistribution and secondary moments on the Magnel diagram is also evaluated. 3 VARIABLE EI CONTINUOUS SPAN ANALYSIS The program BEAM presents a transparent finite element approach for the evaluation of bending moments, shears and deflections for variable EI continuous spans. The following features are available: • for a single span, supports may be fixed, supported or free • up to a six span continuous structure may be analysed • loading may consist of point loads, moments, uniformly distributed loads, support deflection or prestressing The direct prestressing input feature is compared against the equivalent load method for a varying parabolIe tendon force as developed by Catchick. The formulation of the Catchick method is also simplified by the introduction of additional parameters.

M.Ing. / Shaft encoders, are devices generally used in speed and position control applications for sensing position of rotational and linearly moving objects. Most conventional shaft encoders operate on the principle of reading encoded information off a disk, which is fitted to the shaft or using resolver units. Problems are often experienced in fitting high-resolution encoder disks or resolvers to small motors or moving objects. The resolution of an encoder system, using an encoded disk, is a function of the maximum number of slots that are cut in the disk. If the disk itself has to be very small, physical constraints limit the accuracy of the encoder. However, any machined surface will have characteristic marks on it and it is believed that these marks can be used to obtain a unique analogue signature for the shaft. This analogue signature can then be used to gain further knowledge about the rotational speed and possibly the position of the shaft. This project was an investigation into the possibility of gaining accurate, absolute positional information for a rotating shaft. An optical source- and detector system is used in the process of observing the irregularities on the shaft surface. This signal data is gathered and processed using a technique, which compensates for variation in shaft speed during the period in which data is sampled. The entire algorithm, which calculates the absolute position of the shaft from the data gathered, was implemented on a digital signal processor board. Results were evaluated and the maximum non-linearity of the test system was found to vary between 1.8% and 3.7% of full-scale deflection. The resolution of the sensor was between 1.5 and 2.5 degrees with hysteresis between 1% and 1.5% of full scale deflection. The test system allows for rotation in any direction. Possible problems that might be encountered with this type of encoder system are pointed out in this report. Future developments and possible improvements are also discussed.

Bolted connections where used from the beginning of vehicle construction for joining two or more parts. The reliability of bolted connections is still a major problem. The objective of this research thesis is focused on an advanced monitoring system for bolted connections in vehicle construction. A mechanical “vibrating test bench”, which was developed by the aeronautical engineer Mr. Junkers, is being adapted, to suite the requirements of the automotive industry. It is designed according to DIN 65151 standards. The bolted connection is tightened to a specific torque to achieve the required preload forces and then exposed to an oscillating elastic shear force. The preload force and their loss are measured in relation to the number of load cycles. The ideal locking mechanism would be, if no settling occurs. Realistic in practice is the remaining of a sufficient preload force which doesn’t decry with time. The aim of this thesis is, to gain knowledge that will assist in the future control of the bolt locking procedure. The test bench can be used to verify the clamping capability of a bolted connection. With the dynamic computer-aided test system it will also be possible to test critical bolted joints and their safety, which reduces the probability of costly product recalls, or even severe cases of failure.

Some relevant aspects of dynamics and control of heavy-duty hydraulic machines in a teleoperated mode were investigated. These machines, such as excavators and forest harvesters, are mostly used in primary industries. They have a manipulator-like structure with a nonlinear and coupled actuating system. The aim of the project is to investigate different approaches towards converting such machines, with minimum changes, into task-oriented human-supervisory control systems. This provides the opportunity to use both human supervision and robotic power in hazardous environments and for tasks for which human decision is necessary. A methodology was developed for fast and accurate simulations. Analytical, steady-state and numerical techniques were combined using Large-Scale Systems analysis. The inclusion of nonlinearities in the form of discontinuities (e.g., gear backlash and stick-slip friction) in the model was investigated. Numerical simplifications of the structural dynamics and alternative solutions for the hydraulic part were also studied. The model describing the performance of the machine has been written in ACSL (Advanced Continuous Simulation Language) on a VAX computer system. A modified version of the program is at present running close to real-time on a single processor in conjunction with high speed graphics in a manner similar to a flight simulator used for human interface studies and training. The model also evaluates the performance of the machine in a teleoperated mode and under different control strategies. As a result a velocity control algorithm has been developed which is applied in conjunction with the closed-loop components for teleoperation of heavy-duty hydraulic machines; it is basically a feedforward compensation which uses the measured hydraulic line pressures along with fluid-flow equations as criteria to control the joint velocities as well as to uncouple the interconnected actuating system. The control algorithm has been written in C language and is running on an IRONICS computer system, interfaced between the human operator and the machine. The simulation results are supported by the experimental evidence. The experiments were performed on a Caterpillar 215B excavator. Improved operator safety, extension of human capability, job quality and productivity increase are the advantages of a successful implementation of robotic technology to these industrial machines. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

The use of Standards to reduce the complexity of Health Facilities Design has become an indispensable and integral part of the planning process. Unfortunately the structure of present Standards is inflexible, and while this structure may have been acceptable in the past, the standards it produces have become ineffective. Such Standards have been unable to adapt to the changing attitudes and needs of the planning participants who respond to the societal changes around them. It is our objective to develop a method which can build better Standards. In the first chapter we examine the structural problems of Standards and find that there is a fundamental difference between the positive purpose of Standards as used by hospitals and planners and the restrictive purposes of Standards used by government. We have used the terms Guidelines and Standards to denote these different contexts. Having established that a good Standard is one which is similar to a Guideline, we then explore an alternative structure developed at Berkeley, California, called a "Pattern" which we observe will satisfy the requirements for "good" Standards. Since Pattern formats are admirably suited to developing societally-responsive Guidelines and Standards we evolve a method to assemble these new Standards. This method is based upon the Delphi Technique. It uses the technique's inherent advantages to establish communication between two groups of experts (Planners and Medical) who then interact to explore problems and solutions in planning Newborn Nurseries and Neonatal Intensive Care Units. The methodology which is described in Chapter 2 uses the classical components of a Policy Delphi with three rounds of questionnaires sent to Medical Experts (Physicians and Nurses) in various parts of British Columbia and Alberta. It adds such variations as the including of input from the Planner Experts as one method for the feed back of information. This special Delphi design anticipates effects from independent variables and builds in compensatory steps. One of the steps included is a Mini-Survey of a larger group of potential participants, to evaluate the Patterns resulting from the Delphi Study. This larger group was sixteen hospitals in British Columbia and ten hospitals in Alberta. Chapter 3 describes the details in carrying out the three questioning rounds of this modified Delphi method, and its success in assisting the production of a series of Nursery Patterns which are usable as Guidelines. In the methodology is the inherent capability for retaining flexibility, and there are a series of process adjustments that occur. Evaluation of the method in Chapter 4 shows that despite weaknesses, both anticipated and unanticipated, the results provide an important starting point that helps create better, more usable Standards. Possible future developments are briefly mentioned in the hope that evaluation and change will occur as the planning environment changes about us. / Medicine, Faculty of / Population and Public Health (SPPH), School of / Graduate

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The design of the flexure mount recently submitted to NASA Ames for the structural support of the primary mirror of the Space Infrared Telescope Facility (SIRTF) is presented. The flexure system must passively accommodate the differential thermal contraction between the glass mirror and the aluminum structure of the telescope during cryogenic cooldown. Further, it must support the one meter diameter, 116 kilogram (258 pound) primary mirror during a severe launch to orbit. Procedures used to establish the required radial compliance using computer programs NASTRAN and FRINGE are discussed. The parametric design program developed to study early concepts is presented. Methods of combining modal responses resulting from a displacement response spectrum analysis are discussed, and a combination scheme called MRSS, Modified Root of Sum of Squares, is presented. Modal combination schemes using MRSS, SRSS, and ABS are compared to the results of a Modal Frequency Response analysis.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy