Application of the acoustic emission method in order to determine the crack initiation moment in timber

Wooden structural elements frequently develop cracks, which can be dangerous if the elements are under service conditions. Cracks usually propagate parallel to the element axis, and their depth of several centimeters is frequently the same as the thickness of the element. Almost all timber cracks are classified as serious defects. They are responsible for lower strength parameters and lower biocorrosion resistance. The acoustic emission (AE) method, which is commonly used for testing objects or structures made of steel or reinforced concrete, can now be applied to analyze the fracture toughness of timber structures and then diagnose and monitor their safety. This refers to both statically and dynamically loaded elements, e.g. timber support structures in mine galleries.