Week 1 Stress Concentration on a Plate with hole
Aim-
Case :1
Design a plate with a hole model similar to what we worked in the class, but with increased thickness.
Determine the maximum deformation and stress developed in the model.
Plate dimensions:
Length=300mm
Height=120mm
Thickness=30mm
Circular Hole at the center:
Diameter=60mm
Case 2:
smaller holes 90mm away from the center:
Diameter=30mm
Boundary Conditions:
Plate fixed at left face.
Load of 500N on the right face.
Consider you are a Product Engineer in an Automotive industry.
You are assigned the following responsibilities:
- Compare the deformation and maximum stress developed on a structural steel model for the 2 cases
- From an analysis standpoint, which of the design will you select? Explain why?
- From a manufacturing standpoint, which of the design will you select? Explain why?
- Report writing
Procedure-
1) Open Ansys workbench and drag static structural into project schematics
2) Double click on geometry to open spaceclaim, here select plane view and draw a rectangle with a circle at the center as instructed, now pull this geometry to a thickness of 30mm , our model is done, exit the spaceclaim
3) Open model to setup simulation
Go to mesh and insert>>Method>>tertahedron
Element size>>2mm
in Static Structural Add a fixed support to one end of the plate and a force of 1000N to the other end as shown below
In Solutions add Total Deformation and equivalent stress
CASE 2
Exit the model and again double click on geometry, this time select a face of plate and draw 2 circles as instructed now again pull them in the direction of thickness of plate, this results in removal of matrial form plate , exit the space claim
now refresh the project
open model and go to force, change the force from 1000 N to 500 N and solve
Results
| Plate | Maximum Equivalent Stress | Maximum Deformation | Load applied |
| 1 hole | 23.643 MPa | 0.19159 mm | 1000 N |
| 3 holes | 14.747 MPa | 0.1036 mm | 500 N |
Conclusion-
plate with single hole should be selected as the load applied is double but the stress induced are less if the same load would have applied to other plate, also having more holes and sharp edges in model will create more stress and will weaken the part.