· The maximum possible tensile stress in the short fiber is the fiber fracture stress, σ^*_f. 
· The transfer length required to reach this condition is the critical transfer length: 
L = L_c shown in (a) (iii).
· For a fiber shorter than the critical transfer length, L_c , the isostrain condition is not reached at the center of the fiber and the central stress is below the fiber fracture stress. For the case shown (b) the composite will fail when the matrix fracture stress is reached. Fiber pull-out will contribute to the toughness of the composite.