A uniaxial off-axis tensile test is conducted as shown in Figure 4

A uniaxial off-axis tensile test is conducted as shown in Figure 4.5. Using the Tsai–Hill criterion and assuming that the lamina strengths are the same in tension and compression, develop an equation relating the applied stress, σx, to the lamina strengths sL, sT, and sLT, and the lamina orientation, θ, and (b) using the result from part (a), for a unidirectional composite having strengths sL = 1500 MPa, sT = 100 MPa, sLT = 70 MPa, and fiber orientation θ = 60°, determine whether or not an applied stress σx = 200 MPa would cause failure according to the Tsai–Hill criterion