Reliability of Step-Lap Bonded Joints
Final rept. Jan 74-Apr 75
MCDONNELL AIRCRAFT CO ST LOUIS MO
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The objective of the program was an improved technology base of data and methods applicable to the efficient design of graphite-epoxy to titanium step-lap-bonded airframe joints that are optimized for reliability under military flight loading. A random spectrum was used in repeated load tests to establish a data base for defining lifetime and residual strength characteristics. Static strength tests were also conducted which show good comparison with prediction of an elastic-plastic analysis procedure. The static strength, residual strength and lifetime data were assumed to be from Weibull distributions. The shape and scale parameters for each of these distributions were calculated using the best linear unbiased BLU estimation procedure. Using these procedures wearout models were calibrated and checked, and conclusions concerning scaling, and translation of parameters were drawn. Tests were also conducted to determine the effect upon lifetime of load truncation, load frequency, relaxation time between missions, and temperature.
- Attack and Fighter Aircraft
- Couplers, Fasteners and Joints