Development of a load cell for mechanical testing in hydrogen
Abstract
Many tests on materials to determine hydrogen compatibility are performed on small test samples in pressure vessels where monitoring of actual sample load is difficult. A method was developed to monitor small samples by placing inside the vessel a miniature load cell which is capable of measuring loads of less than 100 lbs. The load cell monitors load by means of a Wheatstone Bridge circuit composed of four strain gages. Two of the gages are mounted on a stainless steel stub which becomes part of the vessel load string; the others are wired outside the pressure vessel. Previously, load cells have been shortlived because of hydrogen diffusion into the epoxy phenolic adhesive used to attach the strain gages to the stub. The use of a flame sprayed ceramic, however, rather than an organic epoxy to mount the strain gages appears to produce a load cell resistant to the hydrogen test environment.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- 1982
- Bibcode:
- 1982STIN...8336376M
- Keywords:
-
- Compatibility;
- Hydrogen Embrittlement;
- Loads (Forces);
- Strain Gages;
- Ceramics;
- Circuits;
- Flame Spraying;
- Monitors;
- Pressure Vessels;
- Stainless Steels;
- Wheatstone Bridges;
- Electronics and Electrical Engineering