# Purpose of dividing lines into elements before meshing?

Member
edited August 9

What’s the purpose of dividing lines into any number of elements. If we decrease no of elements, will it impact the strength and stiffness? Actually I am working on Reinforced Beam. If I divide the line describing the steel bar into single element, how will it impact?

• Member

Hello,

Finite Element Method (FEM) divides a given domain into a number of smaller elements. These elements have nodes. The system of equations is solved at these nodes and the solution is interpolated at other locations using shape functions.

Now theoretically, a given body has an infinite number of points and each point has 6 degrees of freedom. So theoretically, any body will have infinite degrees of freedom. But practically, we cannot solve for infinite degrees of freedom. So instead we divide the body into finite number of elements (and hence finite number of nodes and finite number of degrees of freedom). Then we solve for various quantities like displacements, stress, strain etc. at these finite number of locations (i.e. nodes).

So for getting the highest accuracy, you would use highest number of elements possible. But in a practical world, we use as fine a mesh (i.e. as large a number of elements) as is practically possible. So if you use a single element to describe the steel bar, your results most likely won't be accurate. As you increase the number of elements, the accuracy of the solution will increase. But on the other hand, computational cost will increase too. So you need to balance out these two factors.

Hope this helps,

Sai