Dynamic tensile tester

• US 20020017146A1
• Filed: 06/06/2001
• Published: 02/14/2002
• Est. Priority Date: 06/06/2000
• Status: Active Grant

• Current Assignee: Keysight Technologies, Inc.
• Original Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Inventors: Oliver, Warren C.
• Granted Patent: US 6,679,124 B2
• Time in Patent Office: Days
• US Class Current: 73/856
• CPC Class Codes: G01N 2203/0016 Tensile or compressive
• CPC Class Codes: G01N 2203/0017 Tensile
• CPC Class Codes: G01N 2203/028 One dimensional, e.g. filaments, wires, ropes or cables
• CPC Class Codes: G01N 2203/0423 using screws
• CPC Class Codes: G01N 2203/0617 Electrical or magnetic indicating, recording or sensing means
• CPC Class Codes: G01N 2203/0635 using magnetic properties
• CPC Class Codes: G01N 2203/0676 Force, weight, load, energy, speed or acceleration
• CPC Class Codes: G01N 2203/0682 Spatial dimension, e.g. length, area, angle
• CPC Class Codes: G01N 3/08 by applying steady tensile or compressive forces G01N3/28 takes precedence
• CPC Class Codes: G01N 3/38 generated by electromagnetic means

Abstract

A material testing system includes a base and first and second specimen holders. A first displacement sensor measures displacement of the first specimen holder relative to the base. In addition, a second displacement sensor measures displacement of the second specimen holder relative to the base.

Claims

1. A material testing system comprising:

a base;

a first specimen holder;

a second specimen holder;

a first displacement sensor measuring displacement of the first specimen holder relative to the base; and

a second displacement sensor measuring displacement of the second specimen holder relative to the base.

2. The material testing system of claim 1 and further comprising an actuator assembly fixedly coupled to the second specimen holder and operated as a function of the second displacement sensor to dispose the second specimen holder in a known position.

3. The material testing system of claim 2 wherein the actuator assembly comprises an electromagnetic coil coupled to a current source.

4. The material testing system of claim 3 and further comprising a controller receiving a signal from the second displacement sensor and adjusting the current applied to the coil to maintain the second specimen holder in a stationary, known position.

5. The material testing system of claim 3 and further comprising a controller to vary the current applied to the coil to displace the second specimen holder in an oscillating manner.

6. The material testing system of claim 1 wherein the second displacement sensor is a capacitive sensor.

7. A material testing system comprising:

a first specimen holder;

a second specimen holder aligned with the first specimen holder along a common axis;

a first actuator coupled to the first specimen holder;

a second actuator coupled to the second specimen holder;

a controller coupled to the first actuator and the second actuator, the controller operating the first actuator to cause displacement of the first specimen holder away from the second specimen holder, the controller further operating the second actuator to dispose the second specimen holder in a known position.

8. The material testing system of claim 7 wherein the second actuator includes a displacement sensor having a pair of fixed plates and a movable plate coupled to the second specimen holder.

9. The material testing system of claim 8 wherein the second actuator comprises an electromagnetic coil.

10. The material testing system of claim 9 wherein the second specimen holder is maintained in a fixed, known position.

11. The material testing system of claim 9 wherein an oscillatory force is applied to the second specimen holder.

12. The material testing system of claim 7 and further comprising a crosshead coupled to the first specimen holder, the crosshead further coupled to the first actuator.

13. The material testing system of claim 12 wherein the crosshead is coupled to a support frame with a guide mechanism to provide a predetermined path of displacement of the crosshead.

14. The material testing system of claim 13 wherein the guide mechanism comprises a linear bearing.

16. The method of claim 15 wherein the step of applying comprises maintaining the second holder in a first, fixed position.

17. The method of claim 15 wherein the step of applying comprises applying an oscillatory force to the second holder.

18. The method of claim 15 wherein an electromagnetic actuator is coupled to the second holder and the step of applying comprises applying a current to the electromagnetic actuator.

19. The method of claim 18 wherein measuring force on the specimen comprises measuring the current applied during the step of applying.

15. A method for determining elastic and plastic properties of materials, comprising:

attaching a specimen to a first holder and a second holder;

displacing the first holder away from the second holder;

applying a force to the second holder in a direction opposite displacement of the first holder; and

simultaneously measuring extension of the specimen with a first sensor and measuring force on the specimen with a second sensor.

20. A material testing system comprising:

a first specimen holder;

a second specimen holder aligned with the first specimen holder along a common axis;

a first actuator coupled to the first specimen holder;

a load assembly coupled to the second specimen holder and configured to control the second specimen holder to be statically rigid and dynamically compliant.

21. The material testing system of claim 20 wherein the load assembly comprises an electromagnetic coil coupled to a current source.

22. The material testing system of claim 20 wherein the load assembly includes a displacement sensor having a pair of fixed plates and a movable plate coupled to the second specimen holder.