In Chapter 9 of Solid Mechanics I, we looked at calculating the displacement and slope using the double integration method as well as the Macaulay’s function.

Here we present another method (arguably simpler) to work out our displacement and slope: *conservation of energy*. Here’s the equation:

Basically the equation states that the *internal strain energy in the material* must be “inputted” by the *external work done from the action force*. And the external work done is easy enough to calculate:

In Chapter 9 of Solid Mechanics I, we looked at calculating the displacement and slope using the double integration method as well as the Macaulay’s function.

Here we present another method (arguably simpler) to work out our displacement and slope: *conservation of energy*. Here’s the equation:

Basically the equation states that the *internal strain energy in the material* must be “inputted” by the *external work done from the action force*. And the external work done is easy enough to calculate:

If we equate U_{e} with our internal strain energy U_{i} (which we’ve worked out how to calculate
previously), we can get our displacement and slope! Simple isn’t it!

The questions we’ll be looking at will mainly deal with *trusses* or *beams*, which is the most common type of question you will encounter.

Let’s look at an example now.

If we equate U_{e} with our internal strain energy U_{i} (which we’ve worked out how to calculate
previously), we can get our displacement and slope! Simple isn’t it!

The questions we’ll be looking at will mainly deal with *trusses* or *beams*, which is the most common type of question you will encounter.

Let’s look at an example now.