This thesis develops strain and kinetic energy functions and a finite beam element useful for analyzing curved beams which go through large deflections, such as a hockey stick being swung and bent substantially as it hits the ice. The resulting beam model is demonstrated to be rotation invariant and capable of computing the correct strain energy and reaction forces for a specified deformation. A method is also described by which the model could be used to perform static or dynamic simulations of a beam.

The use of laser welding in the automotive industry in the past few decades has facilitated joining of hot-dip galvanized (HDG) steel sheets at high production rates and low cost. The recent development of tailor welded blanks (TWB) using laser welding allowed combinations of sheet grades and thicknesses to “tailor” the vehicle part for optimized design, structural integrity and crash performance but more importantly, reductions in weight. Welded blanks are further subjected to stamping or stretch forming prior to final assembly. Unfortunately, both welding and stretch forming cause the galvanized coating to deteriorate, and thereby, undermine the long term corrosion protection. Despite existing publications on zinc coated steel and advances in processing techniques, there is a lack of understanding on the influence of laser welding and stretch forming on the corrosion performance of HDG steel. Hence, the purpose of this study was to determine how welding speed and biaxial strain affect interstitial-free (IF) and high strength low allow (HSLA) steel coupons when they are subjected to continuous immersion and accelerated corrosion tests. The corrosion rates of the coupons were evaluated using electrochemical techniques and gravimetry. Changes in the galvanized coating were characterized using scanning electron metallography. It was observed that, the original zinc layer transformed into the delta and gamma Fe-Zn intermetallic phases locally in the heat affected zone (HAZ) after laser welding. The resulting microstructure was similar to that of a commercially galvannealed coating and exhibited superior corrosion resistance than that of pure zinc. Linear polarization resistance (LPR) measurements revealed that the zinc coating was able to protect a chemically exposed region of steel in 0.1 M NaCl solution. While the Nd:YAG laser welded coupons with narrow HAZs performed equally well as the non-welded ones, diode laser welded coupons, with a wide locally annealed coating in the HAZ, exhibited a decrease in the peak corrosion rate of zinc. Moreover, minimal amounts of rust were observed on the surface of the HAZ after testing. With biaxial strain, welded and deformed coupons generally demonstrated higher peak corrosion rates than that of undeformed welded ones. When subjected to cyclic corrosion testing according to SAE J2334, rust formed in the exposed region after one 24 hour test cycle due to wet-dry conditions. However, zinc corrosion products on the surface provided substantial corrosion resistance to the remaining zinc coating and to the steel substrate. Gravimetric measurements of welded coupons showed a linear increase in weight gain with increased exposed widths of the steel after 30 cycles but biaxial strain further increased the weight gain on deformed coupons. After 60 cycles, the trend became exponential for both welded and deformed coupons. There was a negligible difference between the corrosion performance of IF and HSLA steel. Using X-Ray diffraction and Raman spectroscopy, species of both iron and zinc corrosion products were identified. Without the application of paint coatings, zinc oxide (ZnO), zinc hydroxy chloride (ZnCl2[Zn(OH)2]4), and hydrozincite ([ZnCO3]2[Zn(OH)2]3) were responsible for passivating the surface and reducing the overall corrosion rate of the galvanized coating.

Development of new scientific disciplines such as bioengineering and micro-nano engineering adopting nonconventional materials requests innovative methodologies that can accurately measure the mechanical properties of soft biological materials and characterize surface energy and adhesion properties of them, independent of measurement conditions. One of emerging methods to measure the deformation of materials under stress is digital image correlation (DIC) technique. As a noncontact strain measurement method, DIC has the advantages of prevention of experimental errors caused by the use of contact type sensors and of flexibility in its application to soft materials that are hard to be tested by conventional method. In the first part of the thesis, 2 dimensional and 3 dimensional DIC codes were developed and optimized, and then applied to two critical applications: 1) determining the stress-strain behaviour of polydimethylsiloxane (PDMS) sample, as a model soft material, using the optical images across large deformation region, and 2) detecting the stiffness variation within the gel mimicking the breast tumour using ultrasound images. The results of this study showed the capability of DIC as a strain sensor and suggested its potential as a diagnosing tool for the malignant lesion causing local stiffness variation. In the characterization of surface energy and adhesion properties of materials, two most common methods are contact angle measurement and JKR-type indentation test. In the second part of the thesis, the experimental set-up for these methods were developed and verified by using the PDMS in static (quasi equilibrium) state. From the dynamic tests, it showed its possible usage in studying adhesion hysteresis with respect to speed. The adhesion hysteresis was observed at high speed condition in both contact angle measurement and JKR-type indentation tests.

The cervical spine ligaments play an essential role in limiting the physiological ranges of motion in the neck; however, traumatic loading such as that experienced in automotive crash scenarios can lead to ligament damage and result in neck injury. The development of detailed finite element models for injury simulation requires accurate ligament mechanical properties at relevant loading rates. The objective of this research was to provide detailed mechanical properties for the cervical spine ligaments, by performing tensile tests at elongation rates relevant to automobile crash scenarios, using younger specimens (less than 50 years old), and to provide a comprehensive investigation of spinal level and gender effects. The five primary ligaments (present between C2-T1) investigated were: the anterior longitudinal ligament, posterior longitudinal ligament, capsular ligament, ligamentum flavum, and interspinous ligament. The craniovertebral ligaments (Skull/C0-C2) investigated were the tectorial membrane/vertical cruciate/apical/alar ligament complex, transverse ligament, anterior atlanto-occipital membrane, posterior atlanto-occipital membrane, anterior atlanto-axial membrane, and posterior atlanto-axial membrane. Tests were performed within an environmental chamber designed to mimic in vivo temperature and humidity conditions, and specimens were preconditioned for 20 cycles at 10% strain prior to testing to failure. Ligaments were tested at quasi-static (0.5s-1), medium (20s-1) and high (150-250s-1). These strain rates were predicted by an existing cervical spine finite element model under typical crash scenarios. Two hundred sixty-one total primary ligament tests were performed, with approximately even distribution within elongation rate, spinal level, and gender. Another forty-four craniovertebral ligaments were tested. Results were plotted as force-displacement curves and the response characteristics determined from the curves were: failure force, failure elongation, stiffness of the linear region, toe region elongation, failure stress, failure strain, modulus and toe region strain. The measured force-displacement data followed expected trends when compared with previous studies. The younger ligaments had less scatter, and were both stiffer and stronger than the older specimens that were reported in previous studies at both quasi-static and comparable higher elongation rates. Statistical analysis was performed on the results to establish significant effects. Strain rate effects were most significant whereas spinal level effects were not found. In general, gender effects were not found to be significantly different, but consistent trends were identified with male ligaments having a higher stiffness and failure force than female ligaments. The post-ultimate load region of the curves was reported to offer insight into the ligament failure mechanism. The characteristic values obtained were used to develop average curves for each ligament, with the intention to eventually be directly integrated into finite element models to better represent the ligament structures. Curves were developed to incorporate the strain rate, spinal level and gender effects for each ligament based on the statistical analyses. Post-failure response was incorporated into these curves because this region has been shown to have an effect on neck behaviour in mathematical models. Recommendations for future studies include measuring accurate cross sectional areas of ligaments during tensile testing to obtain true stress and true strain measurements to better understand if differences in mechanical properties are structural or material. Other possible improvements would be further testing of young cervical spine ligaments with larger sample sizes to further explore spinal level and gender effects. Additional testing performed under identical testing conditions as the current study would allow for pooling of the results effectively increasing the sample size.

An experimental and numerical study of the isothermal and non-isothermal warm formability of an AA3003 aluminum alloy brazing sheet is presented. Forming limit diagrams were determined using warm limiting dome height (LDH) experiments with in situ strain measurement based on digital image correlation (DIC) techniques. Forming limit curves (FLCs) were developed at several temperature levels (room temperature, 100ºC, 200ºC, 250ºC, and 300ºC) and strain-rates (0.003, 0.018, and 0.1s-1). The formability experiments demonstrated that temperature has a significant effect on formability, whereas forming speed has a mild effect within the studied range. Elevating the temperature to 250C improved the formability more than 200% compared to room temperature forming, while forming at lower speeds increased the limiting strains by 10% and 17% at room temperature and 250ºC, respectively. Non-isothermal deep draw experiments were developed considering an automotive heat exchanger plate. A parametric study of the effects of die temperature, punch speed, and blank holder force on the formability of the part was conducted. The introduction of non-isothermal conditions in which the punch is cooled and the flange region is heated to 250C resulted in a 61% increase in draw depth relative to room temperature forming. In order to develop effective numerical models of warm forming processes, a constitutive model is proposed for aluminum alloy sheet to account for temperature and strain rate dependency, as well as plastic anisotropy. The model combines the Barlat YLD2000 yield criterion (Barlat et al., 2003) to capture sheet anisotropy and the Bergstrom (1982) hardening rule to account for temperature and strain rate dependency. Stress-strain curves for AA3003 aluminum alloy brazing sheet tested at elevated temperatures and a range of strain rates were used to fit the Bergstrom parameters, while measured R-values were used to fit the yield function parameters. The combined constitutive model was implemented within a user defined material subroutine that was linked to the LS-DYNA finite element code. Finite element models were developed based on the proposed material model and the results were compared with experimental data. Isothermal uniaxial tensile tests were simulated and the predicted responses were compared with measured data. The tensile test simulations accurately predicted material behaviour. The user material subroutine and forming limit criteria were then applied to simulate the isothermal warm LDH tests, as well as isothermal and non-isothermal warm deep drawing experiments. Two deep draw geometries were considered, the heat exchanger plate experiments developed as part of this research and the 100 mm cylindrical cup draw experiments performed by McKinley et al. (2010). The strain distributions, punch forces and failure location predicted for all three forming operations were in good agreement with the experimental results. Using the warm forming limit curves, the models were able to accurately predict the punch depths to failure as well as the location of failure initiation for both the isothermal and non-isothermal deep draw operations.

Although researchers have begun to show critical interest in men as gendered beings, there has been little in-depth theoretical analysis or scholarly development in the area. Most writing has focused only on defining the problems of men's destructiveness and emotional illiteracy. Virtually no attempts have been made to develop theoretical models capable of cultivating alternative, more psychologically and socially adaptive patterns of male behaviour, identity formation, development and social role acquisition. A small purposively drawn sample of eight profeminist men (nominated by prominent self-declared feminists in the community), along with one men's rights activist, were asked to recount their personal experiences involving gender issues during unstructured interviews. Intensive qualitative analysis, drawing on phenomenological, reflexive postmodern/constructionist and postpositivist/grounded theory techniques, was used to interpret and organize the data into groups of related constructs, which were refined, organized and re-organized according to the emerging schematic model. This model illustrates the complex developmental process of personal profeminist change and social transformation experienced by the nine men interviewed. Their life experiences are presented in separate chapters along with highlighted/annotated variations of the developmental model derived from the interpretive analysis. Analysis revealed that participants were either raised in traditional, patriarchal families or in less traditional, less clearly defined, androgynous family environments. Although both groups of men experienced aspects of gender role strain or incongruence, men raised in patriarchal environments seemed to experience greater strain and more difficulty working through conflicts arising from recent challenges to their masculinity. From an early age, the androgynous men appeared to successfully integrate conflict and shame within the context of rich relationships established under both patriarchal and feminist influences. Only recently challenged by feminism, the men raised exclusively in patriarchy seemed stuck in a somewhat more confusing, vulnerable space between patriarchy and feminism. Several of the more androgynous men acknowledged this gap, and worked to bridge it in their communities by forming alliances and creating synergy through a process of conflict engagement and conflict resolution. As suggested by the men's experiences and the resulting model, integrating gender-related conflict in the contest of a firm, yet compassionate and synergistic community was key to congruent profeminist experience. The strengths, limitations and implications of the model developed herein are discussed in relation to current theory on masculinity, male development and men's role infeminism. Although the model was developed on the basis of intensive analysis of only a small sample of men, it is consistent with current theory and promises to inform psychotherapeutic technique in counselling men.

The steel through-truss Traffic Bridge, located in Saskatoon, Saskatchewan is over one hundred years old. The bridge has been subject to ongoing maintenance throughout its service life. However, inspection reports from 2005 and 2006 highlighted the severe deterioration experienced primarily by the steel members immediately above and below the deck surface. These reports prompted the City of Saskatoon (COS) to implement a rehabilitation project that involved the installation of a post-tensioning system to relieve the badly corroded bottom chord members of the axial loads due to the self-weight of the structure, in 2006. Due to the severe deterioration and the structural modifications that the Traffic Bridge has endured, a limited scope structural health monitoring (SHM) system, based on strain measurements, was implemented to reduce some of the uncertainty regarding the active load paths occurring at the deck level. The objectives of the SHM study were to obtain more information regarding the actual load paths and ascertain possible types of structural redundancy, to determine how to best model this type of structure, and to find ways to track ongoing deterioration using instrumentation. The SHM study involved controlled truck loading scenarios to permit measurement of the load paths and provide data to compare the measured results to a finite element (FE) model of the instrumented span. In addition, random loading scenarios were used to capture the vertical dynamic response of the structure in order to further refine the FE model. This study focused on the response of one-half of one interior span. A total of 72 strain gauges were installed. The downstream truss was highly instrumented at ten locations, three members of the upstream truss were instrumented to measure the distribution, and the floor joists in the downstream lane were instrumented to establish possible redundancy paths. Using an FE model in combination with the measured strain data, it was found that redundant load paths only existed at the level of the deck. The bottom chord members experienced non-zero strains once the control vehicle was past the span, possibly indicating some level of redundancy. The members believed to relieve a portion of the bottom chord tensile forces included the car joists, edge joists, and the timber deck. The amount of force transferred from the bottom chord to the deck members was found by FE analysis to be highly related to the lateral stiffness of the floor beams. The FE model was adjusted to match the measured results by modifying various modelling parameters. The most important features of the model were that all deck elements were modelled to be located at the elevation of the bottom chord, that the lateral stiffness of the floor beams was reduced by 50% to best represent the transfer of forces to deck elements, and that the stiffness of bottom chord members was reduced to 80% of their pristine values. In combination with calibrated modification factors applied to the measured values, this FE model is believed to be a useful tool to represent the behaviour of the structure to assist in detecting further damage by modelling the strain differential between members, and components of members.

Although various approaches to psychotherapy have been applied to The Remains of the Day in the aforementioned analyses, none have linked it to Role Theory, as defined in the context of Psychodrama. However if the abnormal importance that Stevens attributes to becoming a perfect butler is taken into account, The Remains of the Day is practically saturated with textual evidence of how social role imbalance is the source of Stevens’ dilemmas both in the narrated and the narrating time. Although whether it was Ishiguro’s intention to create this effect is unclear, the setting of the novel in a world that is transitioning from the war eras to modernity moreover fits in all too well with the sociological aspects of Role Theory. In brief, it has been proposed that changes in society that render certain social roles obsolete put pressure on the individuals that hold these roles to either adapt or renew themselves in pace with societal developments. Stevens, being a butler, would have felt such strain acutely, being that the decline of the great British houses over the aforementioned period led to a sharp decline in domestic service professions at the time. (Lee, 1988)Drawing upon both the Psycho-dramatic and the Sociologic aspects of Role Theory, this paper aims first of all to propose that Ishiguro’s main character in The Remains of the Day suffers from an over-developed occupational role, which has eliminated or at the very least marginalized his other social roles. Secondly it will argue that the latter’s’ reflections that are brought about over the course of the plot are a consequence of role strain, which as a palpable yet indirect plot element forces him realize that his occupational role is slowly but steadily becoming a thing of the past. In facing such a fate, he is in turn forced to confront how his extreme commitment to his job has left the rest of his life empty, for which he begins to look back at and reconsider the roles that he could have had but neglected in life. On top of outlining this approach to rationalizing the events of the novel, the paper will theorize upon that in choosing to tell such a story, Ishiguro is promoting a view of the world as a place in constant motion, in which, like the post-modernist perspective, there are no set or universal values that withstand the test of time. Juxtaposed against the satirical undertones of the novel, as well as against the time period in which it is set, this statement will in turn be interpreted as critique against the destructive qualities of conventions in society.

<p>This dissertation aims to demonstrate the feasibility of direct infarct visualization using 3D medical ultrasound. The dissertation proceeds by providing the first ever demonstration of fully-sampled 3D ultrasonic speckle tracking using raw B-Mode data of the heart. The initial demonstration uses a Cramer-Rao lower bound limited displacement estimator. The dissertation then proceeds to develop an implementable method for biased time-delay estimation. Biased time-delay estimation is shown to surpass the traditional limits described by the Cramer-Rao lower bound in a mean square error sense. Additional characterization of this new class of estimator is performed to demonstrate that with easily obtainable levels of prior information it is possible to estimate displacements that do surpass the Cramer-Rao lower bound. Finally, using 2D and 3D realizations of biased displacement estimation (Bayesian speckle tracking) the passive strain induced in the ventricle walls during atrial systole is shown to be sufficient to distinguish healthy and chronically infarcted myocardium.</p> / Dissertation

The purpose of this study is to assess the extent to which affiliation with a university research center affects how university scientists allocate their work time across their many academic tasks and responsibilities, including research, teaching, student advising, grants and contracts work, and service and committee duties. The key proposition is that institutional variation across university research centers can affect greatly how center affiliated university scientists allocate their work time insofar as some center level characteristics are more conducive than are others to role strain, which is the structural circumstance (Merton 1957) wherein an individual is beholden to center and departments norms and expectations that are divergent. The concept of role strain befits analysis of the impact of center affiliation on university scientists time allocations insofar as it provides a structural framework with which to characterize the time constraints that center scientists face as a result of being dually obligated to a center and an academic department. Moreover, study at the organizational level of analysis emphasizes competition and even conflict between university research centers and academic departments over the scarce resource of faculty time (Geiger 1990, Stahler and Tash 1994, Mallon 2004). This study uses data from a national survey of university scientists as well as data from interviews with university scientists who affiliate with National Science Foundation Engineering Research Centers or Science and Technology Centers. Survey results demonstrate that a centers size, multidisciplinarity, organization within the university, programmatic ties, and external relations increase the time allocated to research, grants and contracts work, and service and committee duties. These findings constitute objective evidence of center induced role strain (Pandey and Kumar 1997, Rizzo et al. 1970) insofar as they identify components of center scientists work environments suggestive of center and department norms and expectations being divergent and even conflicting. Interview results demonstrate similarly that when a center has no ties to an academic department and when its research focus is applied or commercially relevant, workload increases. These findings constitute subjective evidence of center induced role strain (Pandey and Kumar 1997, Kahn et al. 1964) insofar as it is the center scientists themselves observing these divergent norms and expectations. Implications for policy and theory are discussed.