top of page

# Formula Derivation

## 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

### 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.

## APSEd

APSEd is an E-learning platform for Civil Engineering by IIT-B Graduates. Get access to all in one place!

• Video Lectures & Study Material

• Practice Questions & Mock Tests

• Exclusive Doubt Support

600+ learners are studying with us. Join them and learn with us for an optimized learning experience.

APSEd Founders

Hi! I am Aditya, co-founded APSEd with Palaniappan.

Our brain can accumulate and memorize things to a certain extent. Once it is overloaded, some of the facts and formulas you remembered fade away over time.

All this becomes easier once we understand the concept and know how to apply them. This is what we strive to achieve through our courses.

Our Courses + Your Effort = Success in exams!