STRESS AND STRAIN FOR IMPACT LOAD

Impact load is a load which is applied to a body with some velocity as shown in Figure 12.21. Suppose a load W released from a height h on a collar of a rod of length l and change in length due to impact loading is δl. Now, work done by impact load W is

Figure 12.21 Impact Loading on a Rod

Suppose the equivalent load for same work done is P. Now, work done by equivalent gradual load P

Here, −ve sign is neglected since we are interested to find the maximum stress.

Example 12.12: A steel rod of 10 mm diameter and of 5 m length has collar as shown in Figure 12.22.

Figure 12.22 A Steel Rod with Collar

Find the instantaneous stress and strain when a pull of 200 kN, (i) is gradually applied, (ii) is suddenly applied, and (iii) falls centrally from a height of 120 mm on the collar. E = 200 GN/m²

Solution:

1. For gradually applied load 
2. For suddenly applied load 
3. For impact loading