A composite is fabricated of glass fibers (diameter = 0.03 mm) in an epoxy-resin matrix. All the fibers are aligned parallel to the direction of load application. The volume fraction of fibers is 40%. Assume that the matrix behaves as a rigid-plastic material with a yield strength of 28 MPa and that Ef = 70 GPa and Em= 3.5 GPa. Determine the load-transfer length l, for composite stresses of 70 MPa. Assume that the yield strength in shear is half of the yield strength in tension.