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NASA-LLIS-0204
Lessons Learned - Wind Tunnel Model - Analysis Failure
Year: 1993
Abstract: Description of Driving Event:
During a test run on a model in a wind tunnel, several components of a wooden test rig could not withstand the loads on them with the tunnel at maximum speed. Stress calculations made prior to the mishap indicated an acceptable factor of safety. However, the assumptions in the calculations for stress neglected to consider the drag force on a flat plate which is a multiplier to the dynamic pressure, resulting in a force 80 percent higher than was used in the calculations.
The stress calculations on the model also made certain assumptions that were not consistent with the quality of its material and construction. The investigating committee found that the failed parts were fabricated from inferior wood with numerous knots and that glue was not used to help keep the parts together. The inferior strength of the wood was not noted initially because the model was painted over when delivered to the test site.
During a test run on a model in a wind tunnel, several components of a wooden test rig could not withstand the loads on them with the tunnel at maximum speed. Stress calculations made prior to the mishap indicated an acceptable factor of safety. However, the assumptions in the calculations for stress neglected to consider the drag force on a flat plate which is a multiplier to the dynamic pressure, resulting in a force 80 percent higher than was used in the calculations.
The stress calculations on the model also made certain assumptions that were not consistent with the quality of its material and construction. The investigating committee found that the failed parts were fabricated from inferior wood with numerous knots and that glue was not used to help keep the parts together. The inferior strength of the wood was not noted initially because the model was painted over when delivered to the test site.
Subject: Test & Verification
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T18:25:28Z | |
| date available | 2017-09-04T18:25:28Z | |
| date copyright | 07/06/1993 | |
| date issued | 1993 | |
| identifier other | IIZCQCAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std;jsery=autho47037D83FCDCAC42/handle/yse/207666 | |
| description abstract | Description of Driving Event: During a test run on a model in a wind tunnel, several components of a wooden test rig could not withstand the loads on them with the tunnel at maximum speed. Stress calculations made prior to the mishap indicated an acceptable factor of safety. However, the assumptions in the calculations for stress neglected to consider the drag force on a flat plate which is a multiplier to the dynamic pressure, resulting in a force 80 percent higher than was used in the calculations. The stress calculations on the model also made certain assumptions that were not consistent with the quality of its material and construction. The investigating committee found that the failed parts were fabricated from inferior wood with numerous knots and that glue was not used to help keep the parts together. The inferior strength of the wood was not noted initially because the model was painted over when delivered to the test site. | |
| language | English | |
| title | NASA-LLIS-0204 | num |
| title | Lessons Learned - Wind Tunnel Model - Analysis Failure | en |
| type | standard | |
| page | 2 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1993 | |
| contenttype | fulltext | |
| subject keywords | Test & Verification | |
| subject keywords | Test Article | |
| subject keywords | Test Facility |