Fixture for testing the shear performance of microcellular-foamed thermoplastic composite welds

Patent metadata

Field	Value
Publication number	US-10969313-B2
Application number	US-201716308710-A
Country	US
Kind code	B2
Filing date	Jun 8, 2017
Priority date	Jun 10, 2016
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A lap shear test fixture and method of use to test the performance of the weld interface in welded thermoplastic composite parts such as infrared welded or resistive implant welded or adhesive bonded composite parts. The specimens to be tested are provided from production-ready parts with typical geometry. The test fixture has at least two aligned blocks with at least two lateral support blocks that operably hold the specimen including two welded substrates. The test is performed in compression-mode at a predetermined crosshead speed until the maximum load produced by a universal testing machine makes the weld interface between the two thermoplastic substrates fail in shear mode.

First claim

What is claimed is:

1. A test fixture for measuring the weld interface between thermoplastic composite substrates, comprising:
a first lateral support block operably coupled to a first gripper, said first gripper having a first channel operably for holding a first substrate of a test sample;
a second lateral support block parallel to the first lateral support block and operably coupled to a second gripper, said second gripper located lower than the first gripper and having a second channel operable for holding a second substrate of the test sample, said second substrate welded to the first substrate;
a compression device that applies a load against a loading point of the first lateral support block.

2. The test fixture of claim 1 , wherein the substrates are infrared welded or resistive implant welded or adhesive bonded.

3. The test fixture of claim 1 , wherein at least one of the thermoplastic composite substrates is microcellular-foamed and has a low tensile strength of less than 25 Mpa.

4. The test fixture of claim 1 , wherein the test fixture is a lap shear test fixture to determine the weld strength of the test sample, wherein the test sample is obtained from a production-ready part.

5. A method of testing the weld interface between composite substrates, comprising:
providing a text fixture that is compact having two opposing blocks operably coupled to two grippers;
providing a specimen having two substrates welded together;
loading the specimen into the test fixture;
applying a load to one of the two grippers;
measuring the maximum load required to debond the weld interface between the two substrates.

6. The method of claim 5 , wherein the welding is infrared welding or resistive implant welding or adhesive bonded.

7. The method of claim 5 , wherein at least one of the substrates is a microcellular-foamed thermoplastic olefin substrate or fiber-reinforced thermoplastic composite.

8. The method of claim 5 , wherein at least one of the substrates is has low tensile strength.

9. The method of claim 8 , wherein the tensile strength is less than 25 MPa.

10. The method of claim 5 , wherein the specimen is 20×25 mm and 3 mm thick.

11. The method of claim 5 , wherein the distance between the two grippers is a maximum of 0.02 mm.

12. The method of claim 5 , wherein the upper portion of each of the two blocks is 60×25 and 9 mm thick.

13. The method of claim 5 , wherein the test is performed in compression-mode.

14. The method of claim 13 , wherein the test is performed at a crosshead speed of 1 mm/min until the maximum load produced makes the weld interface between the two substrates fail in shear mode.

15. The method of claim 5 , wherein the test is performed in accordance with DPPD20160419p (ASTM D4501 as reference, 25.4×20 mm, 1 mm/min).

16. The method of claim 5 , further comprising cutting the specimen to 1.0 to 3.0 mm thick.

17. The method of claim 5 , wherein no adhesive is used for the specimen.

18. The method of claim 5 , wherein no adhesive curing is used for the specimen.

19. A compact test fixture for measuring weld interface between two microcellular-foamed thermoplastic composite substrates, comprising:
a first lateral support block operably coupled to a first gripper retaining a first of the two microcellular-foamed thermoplastic composite substrates of a test sample that is welded in at least one predetermined location to a second of the two microcellular-foamed thermoplastic composite substrates of the test sample;
a second lateral support block aligned with and spaced from the first lateral support block and operably coupled to a second gripper retaining the second substrate of the test sample; and
a compression device operable to apply a load against a loading point of the first or second lateral support block, while the other of the first or second lateral support blocks has no direct load applied from the compression device, until a maximum load causes the weld interface between the two microcellular-foamed thermoplastic composite substrates to fail in shear mode.

20. The test fixture of claim 19 , further comprising a first channel formed in the first gripper and a second channel formed in the second gripper, wherein the channels are aligned to hold the test sample prior to application of the load against the loading point and become unaligned when the maximum load makes the weld interface fail in shear mode.

Assignees

• Magna Exteriors Inc

Inventors

• Chitu Marius
• Baltazar Y Jimenez Alexis
• Mori Steven J
• Ward Keith

Classifications

• G01N3/08

  by applying steady tensile or compressive forces (G01N3/28 takes precedence) · CPC title

• G01N3/04 Primary

  Chucks · CPC title

• G01N2203/0296

  Welds · CPC title

• B29C66/727

  being porous, e.g. foam · CPC title

• B29C66/43

  Joining a relatively small portion of the surface of said articles (B29C66/45 takes precedence) · CPC title