Fatigue testing of wood up to one billion load cycles

Abstract Solid birch wood ( Betula pendula ) was investigated with a newly developed ultrasonic resonance test set-up enabling accelerated fully reversed fatigue experiments of wood. Ultrasonic lifetimes were measured at cycling frequency about 20 kHz up to 10 9 load cycles. For comparison, servo-hydraulic tests 50 Hz 5 × 6 performed. Numbers cycles failure plotted against stress amplitudes determined both frequencies show comparable slope and standard deviation in the regime overlapping lifetimes. Birch does not limit. Failures still occurred 8 30 MPa corresponding approximately 35% ultimate compressive strength. Working principles control mode are presented. A modal analysis excited vibration employed train has been performed by finite-element-method. Furthermore, process determination applied strain verified comparative measuring techniques using contact extensometer.