Paper number 368
|SENSOR TECHNIQUES TO VALIDATE THE STRESS INTENSITY IN CRACKED METALLIC PANELS REPAIRED WITH BONDED COMPOSITE PATCHES|
Alan Baker and Bayram Aktepe
Airframes and Engines Division
Aeronautical and Maritime Research Laboratory,
Defence Science & Technology Organisation, Australia
|Summary||Design of bonded composite patch repairs for cracked metallic components is based on finite element or analytical models that determine the stress intensity K in the cracked component following patching and critical stresses in the patch system. To develop confidence in use of these models for the design of critical repairs there is a need to validate them experimentally.
In this paper a direct experimental approach is described in which K in a patched edge-notched specimen is measured using conventional strain gauges or special K-gauges. Measurements were made at various crack lengths and over a range of temperatures. Generalised Westergaard equations with a rotated axis system were used to determine K from the strain measured using conventional gauges while an empirically derived equation was used for the K-gauge.
These experimental results are encouraging since results for both types of gauges were in reasonable agreement with K predicted using the Rose or the Rose/Wang models.
|Keywords|| Bonded composite repairs, fatigue crack growth; stress intensity factors.
Theme : Repair
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