ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 7

Mean Stress Diagrams for Composites Generated Using a Modified Up-and-Down Test Methodology: Part I—Extensive Preliminary Data

Little, RE
Professor of Mechanical Engineering, The University of Michigan-Dearborn, Dearborn, MI

(Received 9 April 1992; accepted 23 February 1993)

Abstract

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.

Keywords:
mean stress diagrams, working stress diagrams, allowable stress diagrams, fatigue, median fatigue strength, up-and-down testing, minimum variance strategy, composites

Paper ID: JTE11780J
DOI: 10.1520/JTE11780J
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