Volume 24, Issue 5 (September 1996)
A Fracture Test Method for Mode I Fracture Of Thin Metal Materials
A method of testing Mode I K dominated fractures in thin materials using a constrained short center notched tension specimen that is clamped along the loaded edge is described. Poisson's effect induces a lateral tension on the specimen that eliminates the buckling problems associated with thin materials. Furthermore, the stress intensity factor over a significant range of crack lengths and specimen geometries is dependent only on the nominal strain, making the test very suitable for crack-growth experiments under a constant-stress intensity factor. A very accurate approximate expression for the stress intensity factor is presented. A test using this method to measure the crack-growth resistance of Kapton 300HN polyimide film is described.