koff07
Mechanical
- Sep 26, 2007
- 1
Hi,
I am designing a 4-point fatigue test (R+) bending jig for unnotched and rectangle steel specimens. The specimen's width and height will be approximately 40x30 mm. The loading and support spans are going to be fixed (non-adjustable).
What aspects should I take into account in jig design and determining specimen's support and loading spans? The maximum normal stress (between loading rollers) and shear stress (between loading and support roller) can be calculated by using beam theory and trying different loading forces, but are there any other stresses I should know?
How can I determine the right diameter for the loading rollers? I understand that the rollers should be free to rotate because of frictional effects. Does the jig's loading and support system need to be articulating or is a rigid system adequate, so that the loads are evenly applied to the test specimen?
Any comments or experiences?
I am designing a 4-point fatigue test (R+) bending jig for unnotched and rectangle steel specimens. The specimen's width and height will be approximately 40x30 mm. The loading and support spans are going to be fixed (non-adjustable).
What aspects should I take into account in jig design and determining specimen's support and loading spans? The maximum normal stress (between loading rollers) and shear stress (between loading and support roller) can be calculated by using beam theory and trying different loading forces, but are there any other stresses I should know?
How can I determine the right diameter for the loading rollers? I understand that the rollers should be free to rotate because of frictional effects. Does the jig's loading and support system need to be articulating or is a rigid system adequate, so that the loads are evenly applied to the test specimen?
Any comments or experiences?
