Mechatronic Systems Engineering 3301A/B Lecture Notes - Lecture 17: Free Variables And Bound Variables, Polycarbonate
12 Aug 2020
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Document Summary
When we seek a better material for an existing application, it is more helpful to compare the new material choice with the existing one. Define a relative penalty function: subscript o: properties of the existing material asterisk *: dimensionless the relative exchange constant * measures the fractional gain in value for a given fractional gain in performance. The contour of that is tangent to the relative trade-off surface identifies the optimum. When logarithmic scales are used, the contours of become curves search area. Trade-off plots reveal the options, and (when combined with the other constraints of the design) frequently point to a final choice. If the relative value of the two metrics of performance (measured by an exchange constant, ) is known, a penalty function, z, allows an unambiguous selection (minimize z) If the casing is insufficiently stiff, it flexes and damages the screen. Casings used to be made of molded abs or polycarbonate.
