Wood fracture, acoustic emission, and the drying process Part 1. Acoustic emission associated with fracture

SummaryAcoustic emission (AE) signals were collected during fracture tests in order to analyze them for characteristics that could be used as parameters in a reactive control system for the wood drying process. Ponderosa pine and California black oak single edge notch tensile specimens were tested in the TR, TL, and mixed mode configurations, at 12 and 18 percent moisture content and at temperatures of 20, 40 and 60 °C. AE was observed in both opening mode and mixed mode tests, but cumulative events to maximum load in mixed mode were 7.4 times greater than in opening mode for oak and 3.4 times greater in pine. It was concluded that mixed mode AE signals were most promising for pattern recognition analysis, which will be the subject of Part II of this study.