Figure 1 is the graphical plot of the tensile modulus of a unidirectional composite material loaded

under isostrain and isostress conditions as a function of volume fraction of reinforcing fiber. Indicate which curve (A or B) is for isotrain condition？ For a given volume fraction of fiber in a composite, which condition is more efficient in increasing the modulus？ If the tensile modulus of the fiber and matrix is known, how can we calculate the tensile modulus of the composite under isostrain condition