Fatigue strength of phenolic molding material
- 1 July 1981
- journal article
- research article
- Published by Taylor & Francis in Journal of Macromolecular Science, Part B
- Vol. 19 (4) , 679-693
- https://doi.org/10.1080/00222348108246316
Abstract
The fatigue strength of some phenolic molding materials containing such fillers as wood flour, glass fiber, calcium carbonate powder, rubber powder, and waste thread were measured at temperatures of 25 to 120C by using a fatigue testing machine based on ASTM D671-71, Method B (under constant amplitude of force). The observed fatigue life curves (S-N diagram) of the phenolic molding materials can be described by an empirical formula QNB + A, where σ is the alternating stress amplitude, N is the number of cycle to failure, and A and B are constants for an individual material. The constant A depends on temperature and is related to the internal friction energy per cycle, δW: A+(E/λ)1/2 where E is the modulus of elasticity and λ is the logarithimic decrement of mechanical damping resulted from the internal temperature and takes values from 0.085 to 0.091. The observed fatigue strengths of the phenolic molding materials at N + 10 7 cycles increased with the value of B and were between 25 and 40% of static flexural strength.Keywords
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