Kurukshetra University 2009 B.Tech Mechanical Engineering Strength of material-ii - Question Paper
Roll No. Total No. of Pages : 2
BT-4/M09 9342Strength of Material-II Paper : ME-206 E
Time : Three Hours] [Maximum Marks: 100
Note Attempt any FIVE questions, selecting at least ONE question from each unit.
UNIT-!
1. Define Strain Energy and derive expressions for Strain Energy stored in a body when load is applied (i) suddenly (ii) gradually
(iii) with impact. 20
2. What is the significance of theories of Failure, discuss in detail the different theories of Failures and their graphical representations. 20
UNIT-II
3. (a) Define Unsymmetrical bending and shear centre. Derive
expression of unsymmetrical bending stating its assumptions.
15
(b) Determine shear centre of channel section.
(10x15x1 cmxcmxcm). 5
4. A boiler drum consists of a cylindrical portion 2m long, Im diameter and 25 mm thick, closed by hemispherical ends. In a hydraulic lest to ION/ mm2 how much additional water will be pumped in, after initial filling at atmospheric pressure ? Assume the circumferential strain at the junction of cylinder and hemisphere is the same for both. For the drum material E * 207,000 N/m: v x 0.3 for water K.= 2100 N/mm:.
?n9342 Contd.
5. A tube 8 cm inside and 12 cm outside diameter is to be reinforced by shrinking on a second tube of ] 6 cm outside diameter. The compound tube is to withstand an internal pressure of 35 MPa and the shrinkage allowance is to be such that the final maximum stress in each tube is to be the same. Calculate this stress and show on a diagram the variation of hoop stress in the two tubes. What is the initial difference of diameters before shrinking on ? E = 200 GPa. 20
6. A steel disc 25 cm outside diameter and 5 cm inside diameter is shrunk on a steel shaft so that the pressure between the shaft and the disc at stand-still is 45 MPa. Assuming that the change in dimensions of the shaft are negligible, find at which speed the disc will loosen from the shaft. Density = 7800 kg/m5 and v = 0.3. 20
UNIT-IV
7. A ring made of 2.5 cm diameter steel bar carries a pull of 10 KN. Calculate the maximum tensile and compressive stresses in the material of the ring. The mean radius of the ring is 15 cm. 20
8. (a) Derive the expression of strain energy for Laminated Springs.
12
(b) A laminated steel spring Im long is to support central load of 5.8 KN. If the maximum deflection of spring is not to exceed 45 mm and maximum stress should not exceed 300 MN/m2, calculate >
(i) Thickness of leaves
(ii) Their number if each plate is to be 80 mm wide
3600
9342
E = 200 GN/ nr. 8
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| Earning: Approval pending. |
