Design Example 15.1 

 Part A:

 Carbon (standard modulus), when embedded in epoxy matrix, meet the stipulated criteria. 

 Carbon (intermediate modulus), when embedded in epoxy matrix, meet the stipulated criteria.
 
 Carbon (high modulus), when embedded in epoxy matrix, meet the stipulated criteria.

 Part B:
 Cost of Carbon (standard modulus) composite is:48.47 
 Cost of Carbon (intermediate modulus) composite is:71.04  
 Cost of Carbon (high modulus) composite is:115.84 

 The material of choice (i.e. least expensive) 
 is standard modulus carbon fiber composite; the relatively low cost per unit mass of this fiber offsets its relatively low modulus of elasticity and 
 required high Volume fraction. 