This thesis investigates Bayesian optimal design for change-point problems. While there is a large optimal design literature for linear and some non-linear problems, this is the first time optimality has been addressed for change-point problems. / In designing a longitudinal study, the decision as to when to collect data can have a large impact on the quality of the final inferences. If a change may occur in the distribution of one or more variables under study, the timing of observations can greatly influence the chances of detecting any effects. / Two classes of problems are considered. First, optimal design for the mixture of densities is investigated. Here, a finite sequence of random variables is available for observation. Each observation may come from one of two distributions with a given probability, which may differ from observation to observation. Such a problem may also be regarded as an application of the multi-path change point problem. Assume subjects may each undergo a single change at random change points with common before and after change point distributions, and at any instant a known proportion of the ensemble of paths will have changed. In either case, the goal is to select which data points to observe, in order to provide the most accurate estimates of the means of both distributions. / Second, we study optimal designs for more classical change point problems. We consider three cases: (i) when only the means of the before and after change point distributions are of interest, (ii) when only the location of the change point is of interest, and (iii) when both the change point and the means of the before and after change point distribution are of interest. / In addressing these problems, both analytic closed form solutions and modern statistical computing algorithms such as Monte Carlo integration and simulated an nealing are used to find the optimal designs. Examples that concern human growth patterns and changes in CFC-12 concentrations in the atmosphere are used to illustrate the methods.

The springback phenomenon was studied by a series of draw-bend tests. These tests were done by varying the blankholding pressure with different lubrication conditions, and with different transverse anisotropy directions. The purpose is to find the forming loads, the thickness changes and the springback angles. It has been found that the springback angle after unloading depends on the amount of blankholding pressure, the material properties, and the tool geometry. Increasing the blankholding pressure almost eliminates the springback if the tensile stress caused by the blankholding pressure reaches the yield in the material. To compliment the experiments, a theoretical model has been developed by calculating the tensile strain developed from applying the blankholding pressure. This strain then was considered in finding the total bending moment.

The first part of the research deals with the estimation of extreme rainfalls for locations where rainfall records are sufficiently available (gaged sites); the second part is concerned with cases where rainfall data are limited (partially-gaged sites); and finally the third part involves the most complex situation where rainfall data are unavailable (ungaged sites). / For gaged sites, two methods were developed for estimating the annual extreme (AE) rainfalls based on the simple scaling behaviour of the first three non-central moments (NCMs) of the AE rainfall processes and using the Generalized Extreme Value (GEV) distribution as the parent distribution. The first estimation method was called one-moment (OM) method since it only relied on the first-order NCM of AE rainfall series in the computation of the rainfall quantiles, while the second method was called three-moment (TM) procedure since it used all first three NCMs of AE rainfalls in the estimation of the quantiles. / For partially-gaged and ungaged sites, a new approach to defining rainfall homogeneous regions has been proposed based on the similarity of rainfall occurrences at different raingage stations. In addition, a Principal Component Analysis technique was used to assess the similarity of raingages and to delineate homogeneous regions. / On the basis of the proposed method for identifying rainfall homogeneous regions, two new methods (PG-1 and PG-2) were developed for estimating annual maximum (AM) rainfalls at partially gauged sites. These methods were also based on the scaling properties of AM rainfall series for different durations. / For ungaged sites, three methods (UG-1, UG-2, and NR) were proposed for estimating AM rainfalls. Method UG-1 was based on the NCMs of AM rainfalls at an ungaged site that were computed by direct interpolation of the corresponding NCM values from the gaged sites within the same homogeneous region. Method UG-2 used the pooled data set from all gaged sites in the homogeneous region for this computation. On the other hand, the NR method estimated the NCMs of AM rainfalls for an ungaged site using the regional regression between the first three NCMs and the number of rainfall occurrence (NR) values that were interpolated from the NR values of the gaged sites. / Finally, to assess the uncertainty of extreme rainfall estimates, two new methods (CI-1 and CI-2) were developed for computing the confidence limits (CLs) based on these estimated values. The proposed methods were based on the bootstrap technique and the scaling properties of the NCMs of extreme rainfall series.

Ice hockey is a sport characterized by high speeds, sharp turns and abrupt stops. As a result of these explosive and agile movements, the interaction of the foot and ankle with the skate boot is fundamental for optimal stability and propulsion. The purpose of this study was to determine the nature of this mechanical coupling in both a conventional and prototype skate models. In phase one, a Biodex System 4 Pro dynamometer was used to isolate the foot and ankle / boot dynamics in sagittal and frontal plane movements. Three footwear conditions were evaluated (control shoe, a skate boot in production and a modified skate boot prototype). In phase two, lower body kinematics were assessed using 3D motion capture to determine if the above skate models would yield different joint movement coordination during skating push-offs using the two skate boot models. When comparing the three foot conditions, there was a significantly greater range of motion observed in the shoe control and modified skate boot than the regular skate boot (65.2 deg vs. 52.4 deg vs. 35.7 deg, p < 0.05). The total work done was only significant in the shoe control over the regular skate boot (16 kJ vs. 8.9 kJ, p < 0.05). In phase two, only the maximum plantar flexion was greater with the modified skate (11.3 deg vs. 1.3 deg, p < 0.05). The biodex dynamometer was able to discern differences between the three types of footwear using the dependent variables selected. Using a combination of the active and passive modes, this system has provided a valuable measurement of quantifying boot stiffness characteristics. / Une vitesse de jeu rapide, les virages brusques ainsi que les arrêts soudains sont des caractéristiques bien particulières au hockey sur glace. Considérant ces mouvements explosifs et agiles, l'interaction entre le pied, la cheville ainsi que la botte du patin devient fondamentale pour obtenir une propulsion et une stabilité optimale. Le but de cette études était de déterminer la nature cette interaction mécanique pour un modèle de patin a glace conventionnel ainsi que pour un prototype. Dans un premier temps, un dynamomètre Biodex System 4 a été utilisé pour isoler de façon dynamique le pied et la cheville/patin dans les plans sagittal et frontal. Trois conditions expérimentales ont été évaluées (soulier contrôle, patin commercialisé ainsi qu'un patin modifié). Par la suite, la cinématique des membres inférieurs fut mesurée en utilisant une système de capture du mouvement pour déterminer si les différentes botte de patin affecteraient la coordination motrice lors d'un départ.En comparant les trois conditions de botte, une différence significative a été observée pour l'amplitude de mouvement entre le soulier et le patin modifié et le patin commercial (65.2° vs. 52.4° vs. 35.7°, p < 0.05). Le travail total était seulement significatif entre le soulier et le patin commercial (16 kJ vs 8.9 kJ, p < 0.05). Pour la deuxième phase, seulement la flexion plantaire maximale était plus grande avec le patin modifié 11.3° vs. 1.3°, p < 0.05).Le dynamomètre Biodex a pu clairement discerner des différences entre les différentes conditions de botte pour les variables dépendantes sélectionnées. En utilisant les modes passifs et actifs, le système a permis de générer une méthode de quantification caractéristique de la rigidité de bottes.

A thin-webbed welded steel plate girder (h/t = 370:1) was tested up to an average shear stress of 13 ksi, or three times the Timoshenko critical load. Local yielding occurred during the initial loading, but subsequent performance was elastic. Strains were recorded in two panels (d/h = 0.5) subjected to combined shear and bending, and in the adjacent stiffeners and flanges.

It is normal practice for civil engineers designing steel beams and columns to assume that the joints are free to rotate, unless they are especially designed as "fixed" joints, in which case it is assumed rotation is completely prevented. In actual fact, however, the joints are semi-rigid. Some rotation does take place, but this rotation is resisted by the joint and creates bending moment at the ends of the beam. The relationship between the joint rotation and bending moment cannot, as yet, be determined theoretically.

The reversed cyclic loading test of an "as-built" bridge column with details typical of those designed and built (Griezic, 1996) in the Montreal area in the 1960's is reviewed. This test emphasized the inadequate design and detailing used at that time and showed how poorly lap-spliced dowels perform under reversed cyclic loading. A retrofitting technique (Griezic, 1996) that employs an added footing block, which moves the location of expected plastic hinging to the top of the lap splice and adds confinement to the lower portion of the lap splice region, and adds an infilled steel shell to confine the column, is also reviewed. / An alternative retrofit technique suitable for corrosive environments is developed and tested under reversed cyclic loading. This retrofit uses an added footing block and a fibre-reinforced, high performance concrete sleeve containing steel hoops in order to confine the column. / Predictions are made on the responses of each retrofit technique, and these are compared to the experimental results. The response of the alternative retrofit technique is analysed and its performance compared to the "as-built" specimen and the column that was retrofitted with an infilled steel jacket. The alternative retrofit specimen increased the strength of the "as-built" column by 53%, compared to an increase of 74% provided by the infilled steel shell retrofit. The alternative retrofit specimen increased the displacement ductility of the "as-built" column from 3.3 to 10.0, compared to 8.3 achieved by the infilled steel shell retrofit. This retrofit technique dissipated almost as much energy as the specimen with the infilled steel jacket retroprofit, and both retroprofit techniques substantially increased the stiffness of the "as-built" column.

The linearized barotropic vorticity equations is solved to investigate the meridional propagation of a forced Rossby wave packet towards a critical layer in a zonal shear flow. The forcing is applied north of the critical layer. Two approaches are employed for solving this problem. First an analytic solution valid for large time is derived, using Fourier and Laplace transform techniques and asymptotic approximations. This solution exhibits the modification due to the wave packet of the corresponding solution obtained by Warn and Warn (1976) in the monochromatic case. / A numerical investigation is then carried out using a finite difference scheme and a time-dependent radiation condition. It is found that the forced waeve packet is absorbed at the critical layer, and the total momentum transferred to the mean flow as a result of the absorption is observed to be proportional to the length scale of the wave packet.

Since blasting is a comminution process, the feasibility of establishing a correlation between the Bond rod mill work index (kWh/t) and some easily measurable physico-mechanical properties relevant to blasting was investigated. Further, the concept of operating blast work index and its potential applications were explored. Four different rock types and a well documented case study of two blasts were selected for this study. / The work index is found to be uncorrelated with the density and unconfined compressive strength, slightly related with tensile strength, and well correlated with dynamic rock properties, especially the P-wave velocity and the bulk modulus. The standard deviation in measured compressive and tensile strength values is found to be very high, compared to their seismic and dynamic elastic properties. / The case study encompassed two blasts with identical blast-patterns and rock type consuming almost the same amount of explosive (kg/t) but with very different specific blast energies (MJ/t). The agreement between operating work index of the two blasts (13.4 kWh/t vs. 13.1 kWh/t) and laboratory work index (17.0 kWh/t) was modest (within 30%). The operating work index corresponding to either blast has been used to predict the product size (P$ sb{80}$) of the other. The choice of feed size (F$ sb{80}$) was discussed; whereas the previous researchers had used the theoretical value of infinity, the use of much smaller value, the average of effective burden and spacing, was proposed. This concept is used in a proposed method to estimate blasting energy requirements as a function of blast geometry, rock type and desired product size. Future test work that would provide a data base and validation for this concept is described.

<p> Methods for modeling structural failure with applications for fluid structure interaction (FSI) are developed in this work. Fracture as structural failure is modeled in this work by both the extended finite element method (XFEM) and element deletion. Both of these methods are used in simulations coupled with fluids modeled by computational fluid dynamics (CFD). The methods presented here allow the fluid to pass through the fractured areas of the structure without any prior knowledge of where fracture will occur. Fracture modeled by XFEM is compared to an experimental result as well as a test problem for two phase coupling. The element deletion results are compared with an XFEM test problem, showing the differences and similarities between the two methods. </p><p> A new method for modeling fracture is also proposed in this work. The new method combines XFEM and element deletion to provide a robust implementation of fracture modeling. This method integrates well into legacy codes that currently have element deletion functionality. The implementation allows for application by a wide variety of users that are familiar with element deletion in current analysis tools. The combined method can also be used in conjunction with the work done on fracture coupled with fluids, discussed in this work. </p><p> Structural failure via buckling is also examined in an FSI framework. A new algorithm is produced to allow for structural subcycling during the collapse of a pipe subjected to a hydrostatic load. The responses of both the structure and the fluid are compared to a non-subcycling case to determine the accuracy of the new algorithm. </p><p> Overall this work looks at multiple forms of structural failure induced by fluids modeled by CFD. The work extends what is currently possible in FSI simulations.</p>