Strain Energy | Overview and
Formula Derivation
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Strain Energy is defined as the internal work done to deform a body by the action of externally applied forces
Let’s say we have an axially loaded bar on which load is applied gradually which increases from 0 to P and due to this load the length of the bar increases by ΔL.
The external work done by the applied load will be given as:
External work = Avg load X Displacement
![External work done](https://static.wixstatic.com/media/c98da3_4fb26a65b35f49048bb217a6e56349f3~mv2.png/v1/fill/w_102,h_61,al_c,lg_1,q_85,enc_auto/w_1.png)
Why are we interested in this strain energy?
Elastic body has a property - it can store this energy when some external force is applied and this energy can be recovered when this external force is removed - so this energy becomes usable to us
Strain Energy Formula Derivation
If we assume that there is no energy loss or in other words if this is a perfectly elastic body then we can say this external work done is equal to internal work done. For a perfectly elastic material,
-
External work done = Internal work done
According to the definition, internal work done is the strain energy stored.
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