Naval Air Development Center, Warminster, Pa.
Pages: 29 Published: Jan 1972
The historic development of airframe structural testing is reviewed and the role played by structural testing in the development of reliable airframe structures is discussed. The threefold safety-factor, safe-life, and fail-safe design approach provides reliable airframe structures when complemented by an effective laboratory test program that includes static, dynamic, and fatigue tests.
Using an iterative analytical and test approach, the operational strength limits of an airframe can be predicted fairly accurately from the static test results. However, predictions of the safe service life from fatigue test data alone leaves much to be desired because of the large variations in service usage. Nevertheless, the alarming cost of modifying aircraft in service has forced an almost complete acceptance of laboratory structural fatigue testing as an economical way of doing business.
The ability to predict the lives (actually the lives remaining) of individual aircraft depends upon the development of an instrument that would measure the fatigue damage actually incurred. Until that time, frequent and rigidly controlled periodic inspections must be performed on all aircraft, and an elaborate scheme of progressive preventive maintenance is mandatory.
predictions, simulation, service life, fatigue tests, static tests, airframes, dynamic tests, failure, plastic deformation, stresses, strains, yield strength
Paper ID: STP34689S