Week 1 Stress Concentration on a Plate with hole

From the following cases given below which of these would be prefered from manufacturing point of view and from analysis point of view?

• Plate with single hole at centre.
• Plate with multiple holes with one in centre and one on either sides from the centre hole.

Solution:

For the 1st case, Plate with single hole.

The given dimensions are,

Length=300mm, Height=120mm, Thickness=30mm, Circular Hole at the center: Diameter=60mm

Left face of the geometry is fixed and there is a load of 500N on the right face.

Procedure:

-First, we open Workbench and create geometry in spaceclaim with the given dimensions.

-Now, exit spaceclaim and open mechanical.

-In mechanical, first we generate mesh with tetra elements.

-Here, I have given element size of 5mm.

-Now, after meshing the geometry we need to provide boundary conditions. Left face fixed and 500N of force on right face.

-Now, the problem is set and we get the solution by giving the solve command.

-To check the deformation of the geometry and stresses induced in the geometry we need to provide Total deformation and Equivalent stress and solve.

-Total Deformation

-Equivalent Stress

Now, for the second case, Plate with multiple holes

The given dimensions are:

Length=300mm, Height=120mm, Thickness=30mm, Circular Hole at the center: Diameter=60mm, smaller holes 90mm away from the center, Diameter=30mm.

Procedure:

-We need to follow the same steps in order to create the geometry with multi-holes. But, there will be just more than 1 hole when compared to previous case.

-Now, we exit spaceclaim and follow the same steps as we followed in the previous case and mesh the geometry with tetra elements with element size of 5mm.

-Now, after meshing the geometry we need to provide boundary conditions. Left face fixed and 500N of force on right face.

-Now, the problem is set and we get the solution by giving the solve command.

-To check the deformation of the geometry and stresses induced in the geometry we need to provide Total deformation and Equivalent stress and solve.

-Total Deformation

-Equivalent Stress

Now, when we compare stresses and deformation from both the cases

Von-misses stress(MPa) Deformation(mm)

Case1 0.60195 0.00027478

Case2 0.5735 0.00029727

Conclusion:

By the results shown above and from basic mechanical point of view. We can say that for industrial manufacturing point of view case1 is preferred, because punching a single hole into the plate is easy than punching three holes without damaging the plate and also deformation is less compared to case2. So, case1 is preferred in Industrial manufacturing point of view.

And as for analysis point of view case2 is preferred because, as you can see in from the picture shown above the stress concentration is equally distributed throughout the plate.