Professor of Mechanical Engineering, The University of Michigan-Dearborn, Dearborn, MI
(Received 9 April 1992; accepted 23 February 1993)
Constant-stress-amplitude axial-load fatigue tests were conducted to generate mean stress data for notched and unnotched specimens of a thermoplastic composite material with 40% (by weight) randomly oriented continuous-strand glass in a polypropylene matrix. Maximum likelihood point and interval estimates for the median fatigue strengths at 107 cycles were computed for four stress ratios R (−1.0, −0.2, +0.2, and +0.6) based on tests conducted following a modified small sample up-and-down methodology appropriate when extensive preliminary data are available to aid in test planning.
Paper ID: JTE11780J