Assignment Problem 11.3

Problem 11.3

Which material property would you select as a guide in material selection if the chief performance characteristics of the components was :

     A)    strength in bending

     B)    resistance to twisting

     C)    the ability of a sheet material to be stretched into a complex curvature

     D)    ability to resist fracture from cracks at low temperatures

     E)     ability to resist shattering if dropped on the floor  

     F)     ability to resist alternating cycles of rapid heating and cooling

Answers

      A)    Ultimate tensile strength will be chosen as material property because it is a properties where the maximum tensile stress that a material can withstand. Example of the material that has quite high ultimate tensile strength are alloy 356-T61 with around 38ksi.

      B)    Modulus of elasticity (Young modulus) will be chosen as guide in material selection because it is a properties where the material resists deformation by bending or twisting to a greater extent.

      C)    Ductility will be the guide in material selection because it is a properties where a material to plastically deform before it fractures. It is usually measured by the percent of the elongation of the material in a test. 

      D)    Fracture toughness will be the guide in material selection because it is a properties where the resistance of a material to the propagation of a crack within it.

      E)     Impact resistance will be the guide in material selection because it is where the ability of a material to withstand sudden shock or impact forces without fracturing.

      F)     Thermal shock will be the guide in material selection because it is where tell that the material properties cracking due to sudden temperatures changes.