Failure behavior assessing of wood strands under tensile loading using acoustic emission technique

With the aim of identifying failure mechanism in oriented strand boards, failure behavior of wood strands under tensile load was investigated using acoustic emission technique. Resinated and unresinated strands were arranged at top, middle and bottom section of the board before pressing. Tensile and acoustic emission tests were performed simultaneously on treated and control samples. Using tensile test data, module of elasticity and ultimate tensile strength of specimens were determined. Acoustic emission data were used for calculating cumulative events, cumulative energy and amplitude of the signals. The results showed that increasing in amount of load and time resulted in increasing of the amount of acoustic emission cumulative energy, event and the maximum signals amplitude. The considerable increase of cumulative energy and events were achieved at the time of failure. The treatment conditions influenced the acoustic emission results and pressed specimens released higher acoustic energy and had higher cumulative acoustic emission events, in comparison to the other specimens. Generally, the magnitude of acoustic emission indices was proportional to mechanical properties such as elastic modulus and tensile strength indicating that failure in strands can be identified by acoustic emission.