# How to simulate the simply supported boundary condition in experiments?

I want to do some experiments on the dynamic behavior of the beam, plate and so on. Four boundary conditions I want to simulate:

• Free
• Clamped
• Simply supported

For free boundary condition, I can use a string to tie the beam or plates up and hang them on some place. For clamped boundary, I can use some bolts to fix the beam or plate on a base. But how can I simulate the simply supported boundary conditions?

• What material will the beam be? Steel, concrete, wood?
– Wasabi
Oct 19, 2016 at 10:44
• I want to use Steel. Oct 19, 2016 at 10:47
• "For free boundary condition, I can use a string to tie the beam or plates up and hang them on some place." That isn't a "free" boundary, unless you replace the "string" with something that is very flexible compared with the test piece itself, You can use something like a suitable grade of bungee cord - or maybe elastic bands, for a small-scale test. You want the natural frequency of the whole test piece "bouncing" as a rigid body on the string(s) to be low - ideally 10 or more times lower than the lowest frequency response that you want to measure. Oct 19, 2016 at 19:26

## 1 Answer

For steel beams, these are relatively simple.

A simply supported beam requires two different supports: one to withstand vertical and horizontal forces (pinned support) and one to withstand only vertical forces (roller support).

Here are examples of each (click the links to see more examples and different types):

Pinned supports

(source: mit.edu)

Roller supports

(source: karcor.com)