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Lessons Learned - Improper Handling of a Test Item Ultimately Resulted in Test Failure

contributor authorNASA - National Aeronautics and Space Administration (NASA)
date accessioned2017-09-04T15:55:04Z
date available2017-09-04T15:55:04Z
date copyright07/12/1994
date issued1994
identifier otherQUBEQCAAAAAAAAAA.pdf
identifier urihttps://yse.yabesh.ir/std/handle/yse/58419
description abstractDescription of Driving Event:
On January 15, 1991, a failure occurred in the 8' Transonic pressure tunnel during testing of a model wing with attached flap. During the test run, the flap peeled away from the wing, broke free, and proceeded down the tunnel. Extensive damage resulted.
It is hypothesized that the east wall flap fitting pin was damaged when the flap was allowed to bend during installation. These pins are stainless steel and approximately 0.38" square. They are inserted into square holes in the tunnel side plates. When the model was installed, the flap was lifted to complete the attachment, was left unsupported during the attachment process, and deflected in the center. This deflection could have caused the square flap fitting pin to become overstressed. The Metallic Materials Branch did, in fact, identify an area of tensile fracture related to a single load incident, but was unable to conclusively establish when the fracture occurred. In any case, engineering should strive to use the lowest stress concentration configuration feasible. In this instance, a round pin on the flap end fitting would have reduced the stress concentrations from the level present on the square pins and perhaps prevented test failure.
languageEnglish
titleNASA-LLIS-0504num
titleLessons Learned - Improper Handling of a Test Item Ultimately Resulted in Test Failureen
typestandard
page2
statusActive
treeNASA - National Aeronautics and Space Administration (NASA):;1994
contenttypefulltext
subject keywordsGround Operations
subject keywordsTest Facility


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