Strength of Materials

Topics: Force, Elasticity, Shear stress Pages: 41 (6269 words) Published: March 21, 2012
Seatwork
1. An aluminum tube is rigidly fastened between a bronze and steel rod as shown. Axial loads are applied at the position indicated. Determine the stress in each material.

2. Two bars are equal length but different materials are suspended from a common support, bar A supports 200lbs and bar B supports 2000lbs, if the cross sectional area of bar A is 0.00015ft2 and bar B is 0.015ft2, compare the strength of bar A and bar B in psi.

Assignment
1. A timber shown in figure with a force of 50kN, compressive with an angle of 30˚ the diameter of 150mm. Calculate the thickness at pt. b and pt. c with the shearing stress of 10Mpa.

2. Truss shown in figure, cross sectional area of the material is 900mm2. Calculate the stress along AB, AC and BD.

Assignment
1. Equate1 and 2. Solve for W in terms of F1 and F2.

2. If the cross sectional area of CA and CB are 700mm2 and 500mm2. Calculate forces CA and CB stress are not exceed 10Mpa and 15Mpa respectively.

Assignment
1. Compute the total elongation caused by an axial load of 100kN applied to a flat bar 20mm thick. Tapering from a width of 120mm to 40mm in a length of 10m as shown in figure. Assume E=200x109N/m2. At section m-n the half width y(mm) at a distance x(m) from the left end. y-20/x=60-20/10, section m-n in a differential length dx. Area section A=20(2y).

2. What is the modulus of elasticity if the stress is 44, 000psi=303.6Mpa and unit strain(ₑ) of 0.00105?

3. A 30m long aluminum bar is subjected to a tensile stress of 172Mpa. Find the elongation if E=69, 116Mpa.

Assignment
1. Determine the safe wall thickness of 30inches steel tank with internal pressure of 7.82Mpa, the yield stress of material is at 275.28Mpa, the factor of safety to use is 2.

2. Determine the bursting steam pressure of a steel shell with diameter of 10inches and made of ¼ thick steel plates. The joint efficiency is at 70% and the tensile strength is 60ksi.

3. At 20˚F, a rigid slab having a mass of 55mg is placed upon two bronze rods and one steel rod as shown. At what temperature will the stress in the steel rod be zero?

Seatwork
1. Two solid shafts of different materials are rigidly fastened together and attached to rigid supports. The aluminum segment is 3inches in diameter and Gal=4x106psi. The steel segment has a diameter of 2inches and Gst=12x106psi. The torque T=10kipin is applied at the junction of the two segments. Compute the maximum shearing stress develop in the assembly.

2. A shaft with a constant diameter of 2inches is loaded as shown by torque applied to gears fastened to it G=12X106PSI. Compute in degrees the relative angle of twist between gears A and D.

Quiz
1. An aluminum tube is rigidly fastened between a bronze rod and a steel rod. Axial loads are applied at the positions indicated. Determine the stress in each section.

2. Block of weight W hangs from the pin at A the bars AB and AC are pinned to support at B and C areas are 600mm2 and 300mm2 respectively. Neglect weights of the bars, determine the maximum safe value of W if the stress in AB is limited to 80Mpa and 90Mpa.

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3. From the truss shown below, determine the stress in members AC and BD.

Midterm
1. An iron column of annular cross section has an outer diameter of 8inches and is subjected to a force of 16.7kn. Find the thickness of the wall if the allowable compressive stress is 1.45ksi.

2. What modulus of elasticity in tension is required to obtain a unit deformation of 0.00105m/m from a load producing a unit tensile stress of 44, 000psi?

3. A force of 10N is applied to one end of a 10inches diameter circular rod. Calculate the stress.

4. A hole is to be punched out of a plate having a shearing strength of 40ksi. The compressive stress in the punch is limited to 50ksi. a) Compute the maximum thickness of plate from which a hole 2.5inches diameter can be punched. b) if the plate is 0.25inch...