The Canadian Design Workshop (CDW) is a new biennial workshop - held in partnership with the Clive L. Dym Mudd Design Workshop - that aims to investigate and share information on design education and research unique to Canadian institutions, focusing on elevating engineering design education and research within the Canadian context. The Canadian engineering education and research landscapes presently share commonalities and important differences from the landscape typically explored during the Clive L. Dym Mudd Design Workshops. This paper discusses the logistics of running the inaugural workshop (CDW1), including challenges and opportunities afforded by the virtual offering. A thematic analysis of the presentations and ensuing discussions during the workshop reveals a number of recurring themes across all sessions, including transdisciplinarity, sustainability, the design studio pedagogy, teaching of design in the "middle years" of engineering programs, and challenges in design education. The paper concludes with a reflection on the first offering of the workshop and implications for the future of CDW.

There is a need in engineering education toimprove the connection between design and engineeringscience. Students should be provided more opportunitiesto practice applying both science and design to a singleproblem in order to be better prepared for challengesthey will face when they enter the workforce. For thisreason, an instructor of a first year engineering sciencecourse was motivated to improve its connection to theCanadian Engineering Accreditation Board (CEAB)Attributes, specifically the Design attribute. The goal wasto revise the course such that the students would berequired to integrate quantitative methods that weretaught during the term through the means of design. Itwas decided that an effective pedagogical tool that couldaccomplish this was a case study, since it would providecomplexity and context using a real-world issue thatrelated to several course concepts. The methodology forcase development, implementation strategy, future steps,lessons learned, as well as the instructor’s observationswill be discussed.

Cyclic behavior of AZ31B spot-welds was studied using different specimen configurations, and compared with steel and aluminum spot-welds. Fatigue strength of magnesium spot-welds was similar to aluminum and less than steel. Three failure modes were observed in tensile-shear specimens and one mode of failure in cross-tension specimens. Fatigue crack initiation life was 50% and 30% of the total life for tensile-shear and cross-tension specimens, respectively. A number of available fatigue models were assessed by predicting fatigue life of magnesium spot-welds. Although these models do not account for the asymmetric cyclic hardening behavior, some of them performed successfully for magnesium spot-welds. (C) 2014 Elsevier Ltd. All rights reserved.

Fatigue testing was conducted on AZ31B-H24 magnesium alloy in strain-control condition. An unusual asymmetric shape of the hysteresis loop was the key feature of the cyclic behavior. A continuum-based cyclic plasticity model was developed to follow the asymmetric hardening behavior of wrought magnesium alloys. The proposed model was implemented in a UMAT subroutine to run with Abaqus/Standard. It was demonstrated that the UMAT was able to follow the cyclic hardening behavior of AZ31B under uniaxial loading. An energy-based damage parameter was proposed for estimating the fatigue crack initiation life. The developed UMAT along with the proposed damage parameter were used for fatigue modeling of an automotive substructure made of magnesium. It was shown that the proposed asymmetric model was more promising than a symmetric model.

A two-passenger, all-wheel-drive urban electric vehicle (AUTO21EV) with four direct-drive in-wheel motors has been designed and developed at the University of Waterloo. An advanced genetic-fuzzy active steering controller is developed based on this vehicle platform. The rule base of the fuzzy controller is developed from expert knowledge, and a multicriteria genetic algorithm is used to optimize the parameters of the fuzzy active steering controller. To evaluate the performance of this controller, a computational model of the AUTO21EV is driven through several standard test maneuvers using an advanced path-following driver model. As the final step in the evaluation process, the genetic-fuzzy active steering controller is implemented in a hardware-and operator-in-the-loop driving simulator to confirm its performance and effectiveness.

The optimum driving dynamics can be achieved only when the tire forces on all four wheels and in all three coordinate directions are monitored and controlled precisely. This advanced level of control is possible only when a vehicle is equipped with several active chassis control systems that are networked together in an integrated fashion. To investigate such capabilities, an electric vehicle model has been developed with four direct-drive in-wheel motors and an active steering system. Using this vehicle model, an advanced slip control system, an advanced torque vectoring controller, and a genetic fuzzy active steering controller have been developed previously. This paper investigates whether the integration of these stability control systems enhances the performance of the vehicle in terms of handling, stability, path-following, and longitudinal dynamics. An integrated approach is introduced that distributes the required control effort between the in-wheel motors and the active steering system. Several test maneuvers are simulated to demonstrate the performance and effectiveness of the integrated control approach, and the results are compared to those obtained using each controller individually. Finally, the integrated controller is implemented in a hardware-and operator-in-the-loop driving simulator to further evaluate its effectiveness.

A two-passenger all-wheel-drive urban electric vehicle (AUTO21EV) with four in-wheel motors and an active steering system has been designed and developed at the University of Waterloo. In order to evaluate the handling and performance of such a vehicle in the design stage and analyze the effectiveness of different chassis control systems before implementing them in the real vehicle, the simulation of a large number of different open-loop and closed-loop test maneuvers is necessary. Thus, in the simulation environment, not only is a mathematical vehicle model needed for every test maneuver, but a driver model must also be designed to simulate the closed-loop test maneuvers. The role of the driver model is to calculate the control inputs required to successfully follow a predefined path. Such a driver model can be implemented as an inverse dynamics problem or by a representation of a driver that can look ahead, preview the path, and change the steering wheel angle and acceleration or brake pedal positions accordingly. In this regard, a path-following driver model is developed in this work with an advanced path previewing technique. In addition, a gain scheduling speed control driver model is developed for the AUTO21EV, which adjusts the drive torques of the wheels to minimize the deviation between the desired and actual vehicle speeds.

A two-passenger all-wheel drive urban electric vehicle (AUTO21EV) with four direct-drive in-wheel motors and an active steering system has been designed and developed at the University of Waterloo. A novel fuzzy slip control system is developed for this vehicle using the advantage of four in-wheel motors. A conventional slip control system uses the hydraulic brake system in order to control the tire slip ratio, which is the difference between the wheel center velocity and the velocity of the tire contact patch along the wheel plane, thereby influencing the longitudinal dynamics of a vehicle.The advantage of the proposed fuzzy slip controller is that it acts as an ABS system by preventing the tires from locking up when braking, as a TCS by preventing the tires from spinning out when accelerating. More importantly, the proposed slip controller is also capable of replacing the entire hydraulic brake system of the vehicle by automatically distributing the braking force between the wheels using the available braking torque of the in-wheel motors. In this regard, the proposed fuzzy slip controller guarantees the highest traction or braking force on each wheel on every road condition by individually controlling the slip ratio of each tire with a much faster response time. The performance of the proposed fuzzy slip controller is confirmed by driving the AUTO21EV through several test maneuvers using a driver model in the simulation environment. As the final step, the fuzzy slip controller is implemented in a hardware-and operator-in-the-loop driving simulator and its performance and effectiveness is confirmed.

This study investigates the cyclic plasticity of AZ31B extrusion under axial and shear loading conditions and presents a continuum-based cyclic plasticity model for the anisotropic behaviour of magnesium. An anisotropic form of the Armstrong-Frederick plasticity model is presented. It is shown that the model can independently produce hysteresis loops under pure axial and pure shear loading conditions. Two different parameters for loading and unloading were considered to address the asymmetric shape of the axial hysteresis loops. The model is evaluated by considering the cyclic stress-strain response of AZ31B extrusion in uniaxial and multiaxial loading cases. Stress amplitude, plastic energy and total energy densities are calculated using the proposed model and are compared with experimental results showing a good agreement.

Resistance spot welds of a magnesium alloy were characterized in terms of microstructure, hardness and monotonic and cyclic properties. Microstructural features in base metal and different zones in the weld region were discussed and the mechanical behavior of spot welds in tensile–shear configuration was studied. Effects of welding parameters were investigated on the micro- and macro-scale characteristics of magnesium spot welds. To this end, five sets of spot weld specimens were prepared, utilizing different welding parameters. The effect of cyclic loading was studied on microstructure and hardness of the base metal and the weld region, and it was shown that microstructural features do not change remarkably under cyclic loading. Fatigue crack initiation and propagation behavior was discussed for different specimen sets under both low and high cyclic loads. Fatigue cracks under high cyclic loading initiated close to the nugget edge, and decreasing the cyclic load nucleated the cracks farther from the nugget.

Tubular specimens machined from extruded AZ31B were tested under cyclic axial and cyclic torsional loading conditions. Pure cyclic axial and pure cyclic torsional behaviour is characterised and presented from macroscopic and mechanistic viewpoints. Unlike the asymmetric hysteresis observed under cyclic axial loading, extruded AZ31B behaves symmetrically under cyclic torsional loading. It is shown that cyclic shear response can be successfully modelled by the Ramberg–Osgood cyclic relation and the corresponding parameters were obtained and presented. This material experiences a significant cyclic hardening and plastic strain reduction in cyclic axial loading. The cyclic shear hardening is less pronounced. Energy, as a scalar valued function independent of direction, is proposed as a potential fatigue parameter that can provide an equivalent damage measure in multiaxial loading for anisotropic materials. It is shown that the total energy densities, the sum of plastic and positive energy densities at half-life, correlate the fatigue data in both axial and torsional loading.

This paper investigates the multiaxial cyclic behaviour of extruded AZ31B magnesium alloy. Tubular specimens were machined from large AZ31B extrusion sections. Two loading modes were considered for multiaxial testing: axial and torsional. All tests were performed at standard laboratory and in as-received conditions. In- and out-of-phase loading at a wide range of strain amplitudes were considered. Nonproportional loading tests were conducted at 45° and 90° phase angle shifts. Correlations between hysteresis shape and deformation mechanisms have been made. Twinning has a major role in deformation under multiaxial loading. Also, it was found that nonproportionality has no significant influence on the fatigue life. Axial and torsional modes were found to have different cyclic behaviour. Fatigue life of AZ31B was examined using different fatigue parameters. Two strain-based parameters based on the critical plane concept were examined. Furthermore, an energy approach was employed as a damage parameter. It was shown that the Fatemi–Socie critical plane model and the Jahed–Varvani energy model provided good estimates to the fatigue life of AZ31B under proportional and nonproportional loading.

This paper presents the experimental results of benchmark coupon testing of monotonie and cyclic conditions on friction stir spot welded coupons of Mg AZ31 alloy. The results presented here are a product of a collaborative multinational research effort involving research teams from Canada, China, and the United States. Fatigue tests were conducted in load control at R=0.1 at two different maximum loads: 1kN and 3kN. Good agreement was found between the participating labs regarding the number of cycles to failure. Differences in the failure modes were observed for the two different loading conditions tested. At the higher load, fatigue failure was caused by interfacial fracture. However, at the lower load, fatigue cracks formed perpendicular to the loading direction, which led to full width separation. For additional comparison, the monotonie and cyclic results of the friction stir spot welds are compared to resistance spot welded coupons of similar nugget size.

ABSTRACT Magnesium alloys are the lightest structural metal andrecently attention has been focused on using them forstructural automotive components. Fatigue and durabilitystudies are essential in the design of these load-bearingcomponents.In 2006, a large multinational research effort, MagnesiumFront End Research & Development (MFERD), waslaunched involving researchers from Canada, China and theUS. The MFERD project is intended to investigate theapplicability of Mg-alloys as lightweight materials forautomotive body structures. The participating institutions infatigue and durability studies were the University of Waterlooand Ryerson University from Canada, Institute of MetalResearch (IMR) from China, and Mississippi StateUniversity, Westmorland, General Motors Corporation, FordMotor Company and Chrysler Group LLC from the UnitedStates. This paper presents the results of benchmark coupontesting that were obtained for monotonic and cyclicconditions on extruded AM30 alloy samples. Tests wereperformed independently in Canada, China, and the US. Ingeneral, the results reported by different institutions were ingood agreement.Microstructure analyses revealed strong material texture witha unique orientation of extension twinning with respect to theinitial basal plane. The cyclic deformation, therefore, wasseen to be dominated by twinning and detwinning. Theunusual asymmetric hysteresis of AM30 observed for fullyreversed cyclic loading is attributed to twinning undercompression in the extrusion direction, detwinning uponunloading from compression and dislocation slip in tension.The monotonic tests were performed under different strainrates and at room temperature or 125°C. Cyclic tests wereperformed under strain controlled conditions. Two strainamplitudes were considered, 0.3% and 0.6% and all fatiguetests were performed under standard laboratory conditions.Raising the temperature from standard laboratory conditionsto 125°C had a significant effect under monotonic loading:both the yield and tensile strength dropped by about 25%,while ductility increased by 300%. Under fatigue loading atroom temperature, extruded AM30 exhibits asymmetricalcyclic behavior at a strain amplitude of 0.6%, whereas thecyclic behavior at 0.3% was symmetric. The material showedsignificant plastic strain recovery, cyclic hardening, and aclear endurance limit.

In this paper a modified multiplicative decomposition of the right stretch tensor is proposed and used for finite deformation elastoplastic analysis of hardening materials. The total symmetric right stretch tensor is decomposed into a symmetric elastic stretch tensor and a non-symmetric plastic deformation tensor. The plastic deformation tensor is further decomposed into an orthogonal transformation and a symmetric plastic stretch tensor. This plastic stretch tensor and its corresponding Hencky’s plastic strain measure are then used for the evolution of the plastic internal variables. Furthermore, a new evolution equation for the back stress tensor is introduced based on the Hencky plastic strain. The proposed constitutive model is integrated on the Lagrangian axis of the plastic stretch tensor and does not make reference to any objective rate of stress. The classic problem of simple shear is solved using the proposed model. Results obtained for the problem of simple shear are identical to those of the self-consistent Eulerian rate model based on the logarithmic rate of stress. Furthermore, extension of the proposed model to the mixed nonlinear isotropic/kinematic hardening behaviour is presented. The model is used to predict the nonlinear hardening behaviour of SUS 304 stainless steel under fixed end finite torsional loading. Results obtained are in good agreement with the available experimental results reported for this material under fixed end finite torsional loading.

Recently, focus has been directed towards using magnesium alloys as materials for automobile vehicle structural components. In automotive applications, load bearing components are subjected to multiaxial fatigue loading. Thus, a better understanding of multiaxial fatigue behavior is a necessary step in the fatigue design of these components. This paper focuses on the monotonic and uniaxial and multiaxial cyclic behavior of extruded AZ31B magnesium alloy. Flat or tubular specimens were machined from large AZ31B extrusion sections. Two loading modes were considered for multiaxial tests: tensile and shear. All tests were performed at standard laboratory and in as-received conditions. Cyclic axial test results indicate that AZ31B exhibit asymmetrical cyclic behavior due to twinning. In contrast, cyclic torsional behavior was found to be symmetric. Energy has been used as a fatigue parameter to correlate the test results.

The explosion of technological complexity has intensified the struggle between depth and breadth in engineering programs. It is difficult for graduating students to work effectively in multidisciplinary teams. Although multidisciplinary projects and courses can address this, a strong foundation of communication and non-technical skills is also required. Case studies are proposed to help develop these skills within disciplinary courses. A novel approach to the development of diverse case studies based primarily on student work term experience is presented. These cases are very motivating and have proven to be an effective and engaging application of course material.

A two-passenger, all-wheel-drive urban electric vehicle (AUTO21EV) with four direct-drive in-wheel motors has been designed and developed at the University of Waterloo. A 14-degree-of-freedom model of this vehicle has been used to develop a genetic fuzzy yaw moment controller. The genetic fuzzy yaw moment controller determines the corrective yaw moment that is required to stabilize the vehicle, and applies a virtual yaw moment around the vertical axis of the vehicle. In this work, an advanced torque vectoring controller is developed, the objective of which is to generate the required corrective yaw moment through the torque intervention of the individual in-wheel motors, stabilizing the vehicle during both normal and emergency driving maneuvers. Novel algorithms are developed for the left-to-right torque vectoring control on each axle and for the front-to-rear torque vectoring distribution action. Several maneuvers are simulated to demonstrate the performance and effectiveness of the proposed advanced torque vectoring controller, and the results are compared to those obtained using the ideal genetic fuzzy yaw moment controller. The advanced torque vectoring controller is also implemented in a hardware-and operator-in-the-loop driving simulator to further evaluate its performance.