STRESS AND STRAIN DUE TO SUDDENLY APPLIED LOAD

Suppose W is a load suddenly applied on the collar of a rod and extension due to the load application is δl as shown in Figure 12.20 (a). The original length of the rod is l. The work done by the load W is U = W × δl

Now consider the equivalent weight for same work is P which is applied gradually.

Work done by gradually applied load P [Figure 12.20 (b)],

Figure 12.20 (a) Suddenly Applied Load W on a Rod and (b) Load and Deflection Graph for Equivalent Gradually Applied Load

Hence, gradually applied load for same work done is equal to two times of suddenly applied load.

Stress produced,