Fatigue behavior of Japanese cypress (Chamaecyparis obtusa) under repeated compression loading tests perpendicular to the grain

Abstract

Abstract The purpose of this study was to gain an in-depth understanding of the fatigue behavior of Japanese cypress as a result of compression. Repeated compression loading tests were conducted on small clear wood specimens in the form of a pulsating triangular wave of frequency 1.0 Hz, and 864000 repeated loading cycles were performed. The change in stiffness and the maximum strain (STRmax) with repeated loadings were investigated, based on the stress-strain relationship obtained from the test. Stiffness hardly changed under conditions of low stress levels (SLs), even under repeated loading. STRmax increased exponentially as the number of loading cycles increased. Furthermore, the fatigue limit was predicted by analyzing the change of STRmax with repeated loading. According to the analysis, the fatigue limit was revealed to be approximately 60% of the SL (standardizing the stress when the strain is 0.05 under static load).