MKCE – DEPARTMENT OF MECHANICAL ENGINEERING

STRENGTH OF MATERIALS

ASSIGNMENT

1. A compound bar consists of a central steel strip 40mm wide and 5mm thick placed between two strips of brass each 40mm wide and X

mm thick. The strips are firmly fixed together to form a compound bar of rectangular section 40mm wide and (2X+5mm) thick.

Determine :

i. The thickness of the brass strips which will make the apparent modulus of elasticity of the compound bar equal to

160 103 MN/m2.

ii. The maximum axial pull the bar can then carry if the stress is not to exceed 160MN/m2 in either the brass or the steel.

Take: Es=207GN/m2 and Eb=114GN/m2.

2. A tie bar has enlarged ends of square section 60mm 60mm as shown in figure. If the middle portion of the bar is also square section, find

the size and the length of the middle portion, if the stress there is 140MN/m2, the total extension of the bar is 0.14mm. Take

E=200GN/m2.

3. Draw the shear force and bending moment diagrams for the beam loaded as shown in figure.

4. The rigid bar BDE is supported by two links AB and CD. Link AB is made of aluminum (E=70Gpa) and has a cross sectional area of

500mm2: link CD is made of steel (E=200Gpa) and has a cross sectional area of 600mm2. For the 30kN force shown, determine the

deflection a) of B, b) of D, c) of E.

5. The structure shown consists of a W250 167 rolled steel beam AB and of two short members welded together and to the beam. A) Draw

the shear and bending moment diagrams for the beam and the given loading. B) Determine the maximum normal stress in section just to

the left and just to the right of point D.

6. For the beam and the loading shown, determine the maximum normal stress on a transverse section at C.

7. The assembly has the diameters and material make up indicated. If it fits securely between its fixed supports when the temperature is

T1=20 C determine the average normal stress in each material when the temperature reaches T2=40 C.

8. Draw the shear force and moment diagrams for shaft. The bearing at A and D exert only the vertical reactions on the shaft. The loading is

applied to the pulleys at B and C and E.

PROPERTIES 2014 - T6

Aluminum

C86100

Bronze

304

Stainless

steel

E (GPa) 74 103 193

α( / C) 23 10-6 17 10-

6 17 10-6