Ultrasonic fatigue of wood
Abstract
Fatigue is the damage to materials caused by cyclic loading and unloading. A large number of cyclic loads can lead to the formation of cracks and finally to fracture, even though all load changes were below the static strength of the material. Material fatigue is one of the most frequent causes of failure of technical components and is therefore of great technical and economic interest. In the present project, the fatigue properties of wood and wood-based materials are to be investigated. In particular, the behaviour at relatively small loads, which can lead to fracture in the range of very high load changes (tens of millions to billions of load changes), is the focus of interest. So far, this has only been scarcely described for wood in the scientific literature, as an experimental investigation with standard servo-hydraulic test equipment and test frequencies of typically 20 Hz takes months to years. Ultrasonic fatigue is a testing technique in which specimens are excited to vibrate at 20 000 Hz instead of being cyclically stressed. The high-frequency stress drastically shortens the testing time, and tests in the tens of millions to billions can be performed within hours to days at most. However, the question arises as to whether the fatigue properties determined at high frequency can be transfered to practice. The vibration frequencies typically occurring in vehicle construction are 1 - 100 Hz and thus more in the range of servo-hydraulic test frequencies than ultrasonic frequencies.
keywords Wood Fatigue Wood composites Strength Ultra sonic
Publikationen
Project staff
Ulrich Müller
Priv.-Doz. Dr. Ulrich Müller
ulrich.mueller@boku.ac.at
Tel: +43 1 47654-89112
BOKU Project Leader
01.06.2021 - 31.12.2022
Herwig Mayer
Ao.Univ.Prof. Dipl.-Ing. Dr.techn. Herwig Mayer
herwig.mayer@boku.ac.at
Tel: +43 1 47654-89202
Sub Projectleader
01.06.2021 - 31.12.2022
BOKU partners
External partners
Innovation Centre W.E.I.Z.
none
partner