Week 1 Stress Concentration on a Plate with hole
Abstract: whenever a uniform plate without any defect is subjected to axial loading the stress distribution along any cross section is uniform however when any hole is present in the plate the stress distribution at the cross section of the plate near the hole more as compare to the other area. The stress calculated about this area is called nominal stress. Stress conc. factor is defined as the ratio of maximum stress to that of nominal stress.
Objective: To determine the maximum stress, nominal stress and stress conc. factor of the plate with hole under axial loading conditions using FEA software Ansys and compare the result of the two different cases.
Material specification:
Structural Steel:
|
properties |
Young modulus |
Yield strength |
Ultimate strength |
Piossions ratio |
|
magnitude |
200 GPa |
250 MPa |
460 MPa |
.3 |
Geometrical specifications:
Comparison of the results:
| CASE 1 | CASE 2 | |
| Total deformation | .00028026 mm | .00029793 mm |
| Equivalent Stress | .6177 MPa | .59351 MPa |
In the case 1 the deformation is less as compare to the the deformation in the second case this is because the area in case one is more compare to the second case and the deformation is given by PL/AE. However the stresses in the second case is less compare to the first case because the strain raiser diagram is smoother in second case compare to first case. The stress concentration factor in second case is less than the first case. (Stress concentration factor is defined as the ratio of maximum stress compare to nominal stress).
Results:
| CASE 1 | |
| DEFORMATION |  |
| STRESS |  |
| CASE 2 | |
| DEFORMATION |  |
| STRESS |  |
For Designer point of view case 2 will be consider because the stress concentration factor is less compare to the first case this is because the stress raiser diagram is smoother in second case.
CASE 1 CASE 2
For Manufacturer point of view the number of operation that they have to carry out in second case is more hence time required for manufacturing the item will be more therefore it would be eaiser to manufacturer the first product, however a production engineer should follow the designed assigned to them by the design engineer.
Conclusion:
- Stress concentration factor in first case is more compare to second case
- the deformation in second case is more compare to the first one.