Answer Happy

Panel walls of refrigerated trucks provide thermal insulation and at the same time they are stiff, strong and light (stiffness to suppress vibration, strength to sustain rough usage). The panels have a sandwich structure with two skins made of steel, aluminum or GFRP (providing the strength) separated by, and bonded to, a low density insulating core. The aim is to select a foam for the core that has a low thermal conductivity and a high stiffness. • The objectives are to minimize the thermal conductivity, and maximize the stiffness of the core, i.e. Young's modulus, E. The free variable is the choice of material. • The constraint is o the panel wall thickness specified. (a) Construct a penalty function. (b) Plot a relevant chart, a trade-off curve and penalty function contours, and discuss how the best choice of foam depends on the relative importance of the two objectives. What material selections do these above suggest? Label the selections on the chart and add density [kg/m?) to the labels.