Abstract

Project-based learning (PBL) has become a common practice engineering schools, often used in the context of design projects. Team based design projects allow the assessment of a broad range of graduate attributes, such as teamwork, communication, professionalism, ethics, project management, problem solving and design. Assessment of these skills is often qualitative, making assessment more difficult and varied than technical, quantitatively assessed subjects.Most often when we grade the outputs of team-based projects, we assess the team as a whole; assigning one grade to the entire team. Whether it is project reports, formative and summative, presentations or group assignments, team members share a mark. Tools such as peer and self-evaluations and contribution attestations are sometimes used to modify the marks assigned to individuals, relating the relative engagement of students within the team, but they do not clearly link the direct learning outcomes of individuals to specific attributes. Shared grading is done for several reasons. Logistically, it is significantly less workload to mark a single report per group, than to mark individual reports. Second, in professional work, the output of a team is what is important, and is the primary indicator of success. In an academic environment however, it is the specific learning outcomes of the individuals that we wish to assess.

Elastomers are finding a wide variety of dynamic applications in aerospace, automobile and biomedical industries. The response of these complex material is based on the loading conditions and the strain rate at which the loading is applied. To suit the designer’s requirement, there is an ever increasing need to characterize this application specific, dynamic behavior under high strain rates. The Kolsky bar apparatus, also known as the Split Hopkinson Bar, is the most common apparatus used to test engineering materials at strain rates between 100/s and 10000/s. In this paper a modified Kolsky bar to characterize soft material is numerically modeled using Finite Element Method. The focus of the study is to numerically analyze the modifications made to a conventional Kolsky bar to specifically test nonlinear hyperelastic, soft materials. The challenge for testing low strength materials is the impedance mismatch between the bar and specimen interfaces, which results in a very weak distorted signal. One of the solution is to use a hollow transmission bar instead of solid one. With the use of FEM it can be numerically verified that using a hollow bar increases the amplitude of the transmitted signal up to several times. It is known that the rise time of the elastic wave can be increased by using a copper pulse shaper. Different dimensions of pulse shaper are modeled and the effect on the incident pulse is analyzed. The main aim of this study is to provide a detailed numerical analysis on the testing parameters, and to model one way wave propagation in Kolsky bar experiment for hyperelastic materials. The constitutive equations used to model the parts of the apparatus are also discussed.

No abstract

Design projects have become common in engineering classrooms. Earlier exposure to and training in the design engineering process hold much value for an enriched experience and an in-depth understanding of engineering design. Simultaneously, students in their earlier years require more guidance and frequent feedback to inform their own expectations of learning objectives, as well as develop effective learning strategies. In this paper, we will examine the considerations required to design and conduct an undergraduate engineering design course, with reflections from several years' experience with a second-year mechanical engineering design course.