A composite sample of carbon reinforced epoxy has dimensions of in 20 in x 20 in x 0.135 in and mass of 3 lb. The carbon fibres have a modulus of elasticity of 80(106) lb/in2 and a density of 0.15 lb/in3. The epoxy matrix has modulus of elasticity of 0.90(106) lb/in2 and a density of 0.05 lb/in3.  Assume there are no voids in the sample, calculate the volume fraction of: (i) The carbon fibres (ii) The epoxy matrix in the sample.

The composite shaft shown consists of a solid brass segment (1) and a solid aluminum segment (2) that are connected at flange B and securely attached to rigid walls at A and C. Brass segment (1) has a diameter of 18 mm, a length of L₁ 235 mm, and a shear modulus of 39 GPa. Aluminum segment (2) has a diameter of 24 mm, a length of L₂ = 165 mm, and a shear modulus of 28 GPa. If a concentrated torque of 270 N-m is applied to flange B, determine (a) the maximum shear stress magnitudes in segments (1) and (2). (b) the rotation angle of flange B relative to support A. N 235 mm (1) B 165 mm Partial Ans: Max shear stress in Member 1 is 55.7 MPa 270 N-m (2)

= 12 mm. The The following figure depicts an aluminum I beam of height h = 0.25 m, width b = 0.2 m, flange thickness ta = 16 mm, and web thickness tw beam is reinforced by two layers of unidirectional composite material of thickness to = 5 mm. The section is subjected to an axial force N₁ = 500 kN. The Young's moduli for the aluminum and unidirectional composite are Ea 73 GPa and Ec 140 GPa, respectively. = (a) Compute the axial stiffness for this structure. (b) Compute the maximum axial stress in both the aluminum and composite layers. CS Scanned with CamScanner 1₁ I h t₂ I b po

Bar A-B-C is made from a fully bonded composite of two materials as shown in the cross section below. Find the Z displacement at point C. A C 1.10 m 20 kN B 1.25 m 50 kN с Y I cross section c-c Uz = 5 mm, material 1 5 mm, material 2 5 mm, material 1 25 mm Material 1 E = 240 (GPa) Material 2 E = 180 (GPa) mm (at C)