BackgroundPrior researchers developed an instrument to measure perceived design thinking ability of first‐year students interested in engineering, and they validated the instrument through exploratory factor analysis.Purpose/HypothesisOur study uses the previously developed instrument to evaluate perceived design thinking ability of senior engineering students. We make a cross‐sectional comparison of this measure on a national scale.Design/MethodWe surveyed a national sample of senior engineering students in 2018 and conducted a cross‐sectional comparison with results from a 2012 national sample of first‐year students who were interested in declaring an engineering major. Two‐way analysis of variance tests compared average design thinking scores across sample groups. Confirmatory factor analysis was conducted to improve the design thinking instrument.ResultsFirst‐year students who intended to declare an engineering major score significantly higher (2.80) on the design thinking scale than senior engineering students (2.59) with a medium effect size of 0.4. The senior engineering sample performs significantly worse on the feedback seeking and experimentalism instrument items, but significantly better on the integrative thinking and collaboration items. We found no significant differences in perceived design thinking ability among engineering disciplines among senior students.ConclusionsFeedback seeking and experimentalism are traits that engineering educators should develop in their students to improve perceived design thinking ability. Incorporation of user‐centered design and divergent thinking in the engineering classroom are recommended as avenues to foster feedback seeking and experimentalism. We also offer recommendations to improve the design thinking instrument for future research.
The use of pressurized blister specimens to characterize the biaxial strength and durability of proton exchange membranes (PEMs) is proposed, simulating the biaxial stress states that are induced within constrained membranes of operating PEM fuel cells. PEM fuel cell stacks consist of layered structures containing the catalyzed PEMs that are surrounded by gas diffusion media and clamped between bipolar plates. The surfaces of the bipolar plates are typically grooved with flow channels to facilitate distribution of the reactant gases and water by-product. The channels are often on the order of a few millimeters across, leaving the sandwiched layers tightly constrained by the remaining lands of the bipolar plates, preventing in-plane strains. The hydrophilic PEMs expand and contract significantly as the internal humidity, and to a lesser extent, temperature varies during fuel cell operation. These dimensional changes induce a significant biaxial stress state within the confined membranes that are believed to contribute to pinhole formation and membrane failure. Pressurized blister tests offer a number of advantages for evaluating the biaxial strength to bursting or to detectable leaking. Results are presented for samples of three commercial membranes that were tested at 80°C and subjected to a pressure that was ramped to burst. The bursting pressures exhibit significant time dependence that is consistent with failure of viscoelastic materials. Rupture stresses, estimated with the classic Hencky’s solution for pressurized membranes in conjunction with a quasielastic estimation, are shown to be quite consistent for a range of blister diameters tested. The technique shows considerable promise not only for measuring biaxial burst strength but also for measuring constitutive properties, creep to rupture, and cyclic fatigue damage. Because the tests are easily amenable to leak detection, pressurized blister tests offer the potential for characterizing localized damage events that would not be detectable in more commonly used uniaxial strength tests. As such, this specimen configuration is expected to become a useful tool in characterizing mechanical integrity of proton exchange membranes.
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