A laminated [0/90/0/90]s graphite/epoxy beam is 1 mm thick, is 20 mm wide, and has 0.125 mm thick plies. The lamina properties are E1 = 180 GPa, E2 = 10 GPa, ν12 = 0.28, G12 = 7 GPa Xt = 1700 MPa, Xc = 1400 MPa, Yt = 40 MPa, Yc = 230 MPa (a) Determine the flexural modulus of the beam (b) How could the flexural modulus be improved without changing the ply materials, the number of plies, or the ply orientations? (c) Using the Maximum Stress Criterion for each ply, determine the magnitude of the maximum allowable bending moment that the beam can withstand. Which ply fails first?

An extruded polymer beam is subjected to a bending moment M. The length of the beam is L = 500 mm. The cross-sectional dimensions of the beam are b₁ = 33 mm, d₁ = 109 mm, b₂ = 20 mm, d₂ = 20 mm, and a = 6.5 mm. For this material, the allowable tensile bending stress is 16 MPa, and the allowable compressive bending stress is 11 MPa. Determine the largest moment M that can be applied as shown to the beam. b₂ a M B A Answer: M = L d₂ N•m b₁ d₁

At a temperature of 60°F, a 0.04-in. gap exists between the ends of the two bars shown. Bar (1) is an aluminum alloy [E = 10,000 ksi; v = 0.32; a = 12.5 x 10-6/°F] bar with a width of 3.0 in. and a thickness of 0.75 in. Bar (2) is a stainless steel [E = 28,000 ksi; v = 0.12; a = 9.6 x 10-6/°F] bar with a width of 2.0 in. and a thickness of 0.75 in. The supports at A and C are rigid. Determine (a) the lowest temperature at which the two bars contact each other. (b) the normal stress in the two bars at a temperature of 250°F. (c) the normal strain in the two bars at 250°F. (d) the change in width of the aluminum bar at a temperature of 250°F. (1) 3.0 in. 32 in. 2.0 in. B ↓ (2) 44 in. 0.04-in. gap Determine the lowest temperature, Tcontact, at which the two bars contact each other.

An extruded polymer beam is subjected to a bending moment M.  The length of the beam is L = 580 mm.  The cross-sectional dimensions of the beam are b1 = 36 mm, d1 = 106 mm, b2 = 22 mm, d2 = 22 mm, and a = 7 mm.  For this material, the allowable tensile bending stress is 20 MPa, and the allowable compressive bending stress is 9 MPa.  Determine the largest moment M that can be applied as shown to the beam.

A component made of Aluminium 6061-T651 has an edge crack with length equal to 15 mm, as shown The yield stress of the material is oy = 280 MPa and its fracture toughness (Kic) ranges from 40 MN/m3/2 to 60 MN/m³/2 Consider now the same edge crack in a semi-infinite plate. Determine the critical stress to avoid fracture. P I I I I ← 15 mm P↓ 100 mm 30 mm

Given your understanding of what initiates and controls failure in materials, which of the following will increase the failure strength or lifetime of a test piece or component and why? a. Decreasing the difference between the maximum and minimum stress values, as this effects the stress concentration factor b. Decreasing the temperature below the brittle-ductile transition temperature, to make it harder C. Polishing to reduce surface defects Od. Increasing its volume, to give a larger cross sectional area Oe. Increasing the grain size so there are less grain boundaries to initiate failure

A cylindrical specimen of brass that has a diameter of 20 mm, a tensile modulus of 110 GPa, and a Poisson's ratio of 0.35 is pulled in tension with force of 40,000 N. If the deformation is totally elastic, what is the strain experienced by the specimen? O 0.00463 O 0.00116 O 0.0029 O 0.01350

#2 will upvote to anyone who will answer

If it is constrained between two supports A and B and is stress-free at 20 ℃, what would be the stress in the two materials when it is heated to 70 ℃, For Steel: Es = 210 GPa, Coefficient of expansion = 12x10^6/℃. For Brass: Eb = 105 GPa, Coefficient of expansion = 19x10^-6/℃

The following shaft is composed of two materials, both rigidly bonded. The data is provided in the table: Determine: The maximum torque that can be applied based on the maximum stresses of each material. The total deformation of the shaft with the torque from the previous section. The maximum torque that can be applied if the maximum deformation of the shaft is 2.50 rad.