MATERIAL SAMPLE FOR TESTING BIAXIAL STRESS CONDITIONS

• US 20110138925A1
• Filed: 08/01/2009
• Published: 06/16/2011
• Est. Priority Date: 08/14/2008
• Status: Active Grant

• Current Assignee: MTU Aero Engines GmbH (MTU)
• Original Assignee: MTU Aero Engines GmbH (MTU)
• Inventors: Pirker, Klaus
• Granted Patent: US 8,601,881 B2
• Time in Patent Office: Days
• US Class Current: 73/788
• CPC Class Codes: G01N 2203/0016 Tensile or compressive
• CPC Class Codes: G01N 2203/0254 Biaxial, the forces being applied along two normal axes of the specimen
• CPC Class Codes: G01N 2203/0282 Two dimensional, e.g. tapes, webs, sheets, strips, disks or membranes
• CPC Class Codes: G01N 3/165 generated by rotation, i.e. centrifugal force for testing structures or apparatus G01M99/004

Abstract

Described is a material sample for testing material properties under biaxial load as well as a method therefor. The material sample has a circular disk shape and, for rotation about the center line thereof, is provided with an integrally formed hub. The edge of the material sample and the hub are thicker than the ring section of the material sample located in between. In one embodiment, the ring section is designed with an annular concave fillet concentric to the hub and the concave fillet may extend from the edge to the hub and have a continuous curvature over its width. In the method, it is rotated about its center line at least at 100,000 rpm, preferably at 150,000 rpm±10,000 rpm.

Claims

1. A material sample for testing material properties under biaxial load, hereby characterized in that the material sample (1) has a circular disk shape and, for rotation about its center line (17), has an integrally formed hub (12), with the edge (11) of the material sample (1) and the hub (12) being thicker than the ring section (14) of the material sample located in between.

2. The material sample according to claim 1, further characterized in that the ring section (14) is designed with an annular concave fillet (13) concentric to the hub (12).

3. The material sample according to claim 2, further characterized in that the concave fillet (13) extends from the hub (12) to the edge (11).

4. The material sample according to claim 2 or 3, further characterized in that the concave fillet (13) has a continuous curvature over its width.

5. The material sample according to claim 4, further characterized in that the curvature is a circular arc.

6. The material sample according to claim 4, further characterized in that the curvature is an elliptical section.

7. The material sample according to one or more of the preceding claims, further characterized in that the ring section (14) and the edge (11) of the disk-shaped material sample (1) are symmetric with respect to their center plane.

8. The material sample according to one or more of the preceding claims 1 to 7, further characterized in that the hub (12) has a stay bolt (15), which extends from the hub center concentrically to the center line (17) of the material sample (1).

9. The material sample according to one or more of the preceding claims 1 to 7, further characterized in that the hub has a threaded bore, which extends concentrically to the center axis into the material sample.

10. The material sample according to one or more of the preceding claims, further characterized in that the material sample has a diameter of 50 mm to 100 mm.

11. The material sample according to one or more of the preceding claims, further characterized in that the material sample (1) has a diameter of 76 mm±

5 mm.

12. The material sample according to one or more of the preceding claims, further characterized in that the edge (11) of the material sample (1) has a thickness of 8 mm±

2 mm.

13. The material sample according to one or more of the preceding claims, further characterized in that the ring section (14) of the material sample (1) has a minimum thickness of 3 mm±

2 mm.

14. A material testing setup for testing materials under biaxial load, having a material sample (1) according to one or more of claims 1 to 13 and an arbor (16), which is joined to the hub (12).

15. A material testing machine for testing materials under biaxial load, having

a material testing setup according to claim 14 and

a drive device having a drive shaft (18) that can be coupled to the arbor (16).

16. The material testing machine according to claim 15, further characterized in that the drive device is designed to rotate the drive shaft (18), together with the material sample (1) coupled thereto, at over 100,000 rpm.

17. The material testing machine according to claim 15, further characterized in that the drive device is designed to rotate the drive shaft (18) with the material sample (1) coupled thereto at 150,000 rpm±

10,000 rpm.

18. A method for testing material properties under biaxial load, based on a material sample that has a circular disk shape and, for rotation about its center line, has an integrally formed hub, wherein the edge of the material sample and the hub are thicker than the ring section of the material sample located in between, having the step:

rotation of the material sample about its center line at least at 100,000 rpm.

19. The method according to claim 18, further characterized in that the speed during the test is 150,000 rpm±

10,000 rpm.