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Accelerated Tensile-Tensile Fatigue S-N Curve Characterization of PP-GF30 and PA66-GF50 using Block Testing and Cumulative Damage Theory


Title: Accelerated Tensile-Tensile Fatigue S-N Curve Characterization of PP-GF30 and PA66-GF50 using Block Testing and Cumulative Damage Theory

Authors: Sara R. Johnson, Eric O. Kerr-Anderson

DOI: 10.33599/nasampe/c.23.0132

Abstract: Fatigue performance is one of the most expensive features of a material to characterize. The creation of a simple S-N curve can tie up one fatigue machine for up to a month and cost thousands of dollars. The use of block fatigue testing and cumulative damage theory represent an alternative to generate the same S-N curve in less than a week. A traditionally created tensile-tensile baseline S-N curve was generated for PP-GF30 and PA66-GF50 to compare to several block testing setups with interesting results. The first block test consumed a large amount of the fatigue life quickly at high loading prior to dropping to a lower cycle loading to finish. The count to failure in the second block was divided by the remaining fatigue life percentage to extrapolate the number of cycles to failure at the lower load. The reverse of this was also tracked by loading at a low load first for a certain number of cycles and finishing at a high load cycle to failure. The third method evaluated was to replicate real world conditions by changing back and forth with multiple blocks between high and low loading. The last method evaluated was to go from a low load block to a high load block while changing the lower limit of the high load to maintain cyclic strain energy from block to block. These studies resulted in outcomes that do not fully conform with cumulative damage theory and require further study.

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Conference: CAMX 2023

Publication Date: 2023/10/30

SKU: TP23-0000000132

Pages: 9

Price: $18.00

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