Patent ID: 8707797

Claim:
A sample for fatigue and crack growth testing, comprising: (a) a length of the material to be tested comprising: (i) a first and second end; and (ii) an axisymmetric shape on the exterior over at least a portion of its length; and (b) a substantially circular hole extending from the first end of the sample along its longitudinal axis to a depth such that its terminus lies in the midst of the said axisymmetrically shaped portion, wherein: (i) the hole is concentric with said axisymmetric portion; and (ii) the hole has a constant diameter along at least a portion of its length in the vicinity of the terminus; and (iii) the region of the terminus of the hole forms a notched shape to initiate and/or grow cracks in the specimen under cyclic loading; and (c) at least two means of contacting a test machine capable of transmitting loads, wherein: (i) a first means introduces load in the vicinity of the terminus of the hole; and (ii) a second means introduces load at or near the first end of the sample, distributing load in a substantially axisymmetric manner around the sample axis.