Professor, The University of Michigan-Dearborn, Dearborn, MI
(Received 19 February 1996; accepted 31 January 1997)
This paper summarizes an experimental study of how three specimen thicknesses—⅛, 3/16, and ¼ in. (3.18, 4.76, and 6.35 mm)—affect the long-life fatigue performance of a thermoplastic composite material with 40% randomly-oriented continuous-strand glass in a polypropylene matrix (Azdel). Axial-load and four-point-bending fatigue tests were conducted to compare (1) the respective median logarithmic fatigue lives for a common alternating stress amplitude and (2) the respective estimated median fatigue strengths at 107 stress cycles. Both the median logarithmic fatigue life and the median fatigue strength decreased markedly when the specimen thickness was increased from ⅛ to 3/16 in. (from 3.18 to 4.76 mm). However, in each case, no further decrease was statistically evident when the specimen thickness was increased from 3/16 to ¼ in. (from 4.76 to 6.35 mm).
Paper ID: JTE11359J