Page 81 - Fundamental of Engineering Design

Example 3

A cylindrical block is 30 cm long has a circular cross-section

10cm in diameter. It carries a total compressive load 70kN, and

under this load it contracts by 0.02cm. Estimate the average
compressive stress over a normal cross-section and the

compressive strain.

70 kN

Solution: 10cm
diameter
A= π 0.10 2 = 7.85 X 10 m 2
−3
4

30cm
The average compressive stress over this cross-section is then

σ = = 70 103 = 8.92 MN/m 2
7.85 10 −3

The average compressive strain over the length of the cylinder is

−3 70 kN
ε = 0.02 10 = 0.67 x 10 −3
30 10 −3
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