Thermal emission flaw detection method
AssigneeGrumman Aerospace Corporation
InventorBenjamin J. Aleck
Life of this patent
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Abstract
A method of detecting very small structural flaws at loads below those which cause the flaws to propagate is disclosed. Certain phenomena and relationships of fracture mechanics are utilized in conjunction with the generation, detection and interpretation of thermal emission signals indicative of plastic deformation of the tested material.
Claims9
A nondestructive method for detecting flaws in a structure comprising a material having a characteristic threshold stress intensity factor, including the steps of:
- (a) loading the structure at a level corresponding to a stress intensity factor below the characteristic threshold stress intensity factor of the material;
- and
- (b) positioning detection means in thermal proximity to the structure for detecting thermal emission signals indicative of plastic deformation.
A nondestructive method for detecting flaws in a structure comprising a material having a characteristic threshold stress intensity factor, including the steps of:
- (a) cyclically loading the structure at a level corresponding to a stress intensity factor below the characteristic threshold stress intensity factor of the material;
- and
- (b) positioning detection means in thermal proximity to the structure for detecting thermal emission signals indicative of plastic deformation.
A nondestructive method for detecting flaws in a structure comprising a material having a characteristic threshold stress intensity factor, including the steps of:
- (a) resonantly loading the structure;
- (b) cyclically loading the structure at a level corresponding to a stress intensity factor below the characteristic threshold stress intensity factor of the material;
- and
- (c) positioning detection means in thermal proximity to the structure for detecting thermal emission signals indicative of plastic deformation.
Dependencies are inferred from the claim text.