A Local Load Sharing (LLS) model recently developed by Curtin and co-workers for the numerical simulation of tensile stress-strain behavior in fiber-reinforced composites is used to predict the tensile strength of metal matrix composites consisting of a Titanium matrix and unidirectionally aligned SiC fibers. This model is extended to include the effects of free boundary conditions and non-constant load gradients and then used to predict the strength of a Ti-6Al-4V matrix reinforced with Sigma SiC fibers under 4-point flexure testing. The predicted tensile and flexure strengths agree very well with the values measured by Gundel and Wawner and Ramamurty et al. The composite strength of disordered spatial fiber distributions is investigated and is shown to have a distribution similar to the corresponding ordered composite, but with a mean strength that decreases (as compared to the ordered composite) with increasing Weibull modulus. A modified Batdorf-type analytic model is developed and similarly extended to the case of non-uniform loading to predict the strength of composites under tension and flexure. The flexure model is found to be inappropriate for application to the experimental materials, but the tensile model yields predictions similar to the Local Load Sharing models for the experimental materials. The ideas and predictions of the Batdorf-type model, which is essentially an approximation to the simulation model, are then compared in more detail to a simulation-based model developed by Ibnabdeljalil and Curtin to more generally assess the accuracy of the Batdorf model in predicting tensile strength and notch strength versus composite size and fiber Weibull modulus. The study shows the Batdorf model to be accurate for tensile strength at high Weibull moduli and to capture general trends well, but it is not quantitatively accurate over the full range of material parameters encountered in various fiber composite systems. / Master of Science

Yes / Detailed electricity load profile for domestic building is an important requirement for the accurate analysis of demand side management. The use of electrical appliances within domestic buildings varies significantly with respect to time, mainly in accordance with the activity and behaviour of the occupants. This paper presents results from a monitoring study of electrical energy consumption profiles for One UK household (two adults with children). Measurements for whole household electricity consumption have been obtained over a period of ten months. They were all obtained at one minute interval. Monthly energy consumptions, daily and overall profiles were derived for this household type from the monitored data. It is intended that the results presented in this paper can be used in the quest for a precise forecast method for electricity consumption for occupants living in the same type of household in the UK. This will allow greater confidence in the sizing of, e.g., adopting renewable energy sources in this type of household. Further investigation is needed for a large sample of households to improve the understanding of monitoring high resolution domestic energy consumption. / MSCRC

Yes / Electricity Suppliers in competitive electricity markets commonly respond to prices changes which are fluctuating over time, but most consumers respond to the price changes as reflected on their electricity bills. Almost all consumers pay fixed tariffs for their consumption without distinctions based on usage time, so these consumers have had no incentives to reduce their use during the peak times. This paper aims to analyze the influence of different tariff schemes on consumer behaviours in UK domestic buildings. A realistic half hourly electricity load profile for different types of UK households that based mainly on public reports and statistics has been generated. This load profile data were used to help calculate the expected change in consumers' bills under standard tariffs offered from different suppliers to what the cost of electricity would be under time varying tariff (economy7 tariff) and to estimate of how much consumers would shift their load in response to price changes without changing total consumption, for which the results are presented and discussed / MSCRC

Yes / Test results of 24 reinforced concrete continuous deep beams are reported. The main variables studied were concrete strength, shear span-to-overall depth ratio (a/h) and the amount and configuration of shear reinforcement. The results of this study show that the load transfer capacity of shear reinforcement was much more prominent in continuous deep beams than in simply supported deep beams. For beams having an a/ h of 0.5, horizontal shear reinforcement was always more effective than vertical shear reinforcement. The ratio of the load capacity measured and that predicted by the strutand-tie model recommended by ACI 318-05 dropped against the increase of a/h. This decrease rate was more remarkable in continuous deep beams than that in simple deep beams. The strut-and-tie model recommended by ACI 318-05 overestimated the strength of continuous deep beams having a/ h more than 1.0.

Yes / Energy consumers oftentimes suffer some element of discomfort associated with the implementation of demand response programs as they aim to follow a suggested energy consumption profile generated from scheduling algorithms for the purpose of optimizing grid performance. This is because people naturally do not like to be told what to do or when to use their appliances. Although advances in renewable energy have made the consumer to also become energy supplier, who can actively cash in at times of the day when energy cost is high to either sell excess energy generated or consume it internally if required, thereby nullifying the adverse effect of this discomfort. But a majority of consumers still rely wholly on the supply from the grid. This impact on users' comfort who are active participants in demand response programs was investigated and ways to minimizing load scheduling discomfort was sought in order to encourage user participation.

No / This paper presents a numerical modelling method to predict the shear behaviour of typical wall-stud cold-formed steel wall panels subjected to in-plane monotonic loads. In the research presented in this paper, different material and mechanical properties for cold-formed steel sheets, self-drilling screwed connectors and wall fixing boundary conditions were considered to explore the influence of sheath sheeting, connectors and fixing boundary conditions on the structural behaviour of selected wall panels. After the FE model being validated against experimental results, a parametric study was conducted and the comparison and analysis highlight the effect of different sheaths, connectors on to the structural shear behaviour of typical wall-stud cold-formed steel wall panels.

A postbuckling analysis procedure for simply-supported, symmetrically laminated, rectangular, generally orthotropic plates under uniaxial compression based on a Marguerre-type energy method was developed. The analysis assumes the out-of-plane displacement to be represented by using a truncated Fourier sine series. The unknown coefficients of the displacement function were obtained from a system of nonlinear algebraic equations by using the principle of minimum potential energy. The number of terms that are to be retained in the out-of-plane displacement function to obtain an accurate response was studied and identified for a wide range of generally orthotropic plates. In the postbuckling load range, plates are also allowed to change their buckled form. The magnitudes of the total potential energy for possible different deformed shapes of a plate were compared to determine the actual deformed shape. The effect of bending-twisting coupling terms on the postbuckling behavior of anisotropic laminates was also investigated. Several postbuckling problems for isotropic, orthotropic, and anisotropic plates were considered and the results obtained by the present approach were compared with available literature results and finite element solutions to demonstrate the present analysis procedure. The analysis procedure developed was, then, applied to minimum-weight design of laminated plates for postbuckling performance. Laminate failure load used in the postbuckling regime was calculated based on a maximum strain failure criterion. The failure criterion was demonstrated to predict the failure load reasonably well when compared with available test results. Weight comparison between the plates designed against buckling and the ones designed for the postbuckling strength was made to quantitatively evaluate the weight savings achieved for plates that are allowed to buckle. The design variables were assumed to be the layer thicknesses with specified fiber orientations and assumed to take only discrete values. A simple approach based on the penalty method was proposed to achieve the discrete-valued designs. In addition to the regular penalty terms for constraint violation, the proposed approach introduces penalty terms to reflect the requirement that the design variables take discrete values. A variable magnitude penalty term in the form of a sine function was implemented with the extended interior penalty method of the optimization package NEWSUMT-A. The proposed discrete optimization technique was applied to the classical truss and laminated composite plate design problems to demonstrate the performance of the procedure. / Ph. D.

A continuous vorticity panel method is developed and utilized to predict the steady aerodynamic loads on lifting surfaces having sharp-edge separation. Triangular and semi-infinite panels with linearly varying vorticity are used. The velocity field generated by an individual element is obtained in closed form. A concentrated core of vorticity is employed to simulate the leading-edge-vortex core and its feeding sheet. An optimization scheme is constructed for finding the vorticity at the nodes of the elements. The method is not restricted by aspect ratios, angles of attack, planforms, or camber. The numerical results are in good agreement with the experimental data for both rectangular and delta wings for incompressible flows. / Ph. D.

This paper is an extension of various projects that the writer has been associated with at Chance Vought Aircraft, Incorporated.

This dissertation aimed to expand knowledge and practical uses of educational technology tools in high-stakes team training environments. This study depicted the real-world impacts of virtual reality (VR) technology on learning and training for the Royal New Zealand Police Academy and those training teams in high-stakes environments. Recommendations for improvement in designing these technologies and training resulted from the study. The study involving VR and the Bedford Workload Scale employed pre- and post-training to determine if using that technology produced statistical significance and improved user learning in VR tactical police training. The final study resulted in similar pre- and post-test results from participants (n = 74), indicating VR may produce realistic levels of cognitive load in virtual participants, and one statistically significant finding for participants who had previous experience using VR, suggesting that cognitive load may be higher during training for those with previous experience. The findings revealed that VR shows promise for increasing the value and efficacy of compliance training in tactical police settings and similar high-stakes team training environments.