NDE OF WOOD-BASED COMPOSITES WITH LONGITUDINAL STRESS WAVES.

The research presented in this paper reveals that stress wave nondestructive testing techniques can be used to evaluate the tensile, flexural, and internal bond properties of wood-based composite materials. Results of preliminary tests indicated that wave speed and attenuation were material properties related to the same mechanisms that control these materials' mechanical behavior. Results of an experimentation program designed to develop and explore mathematical relationships between stress wave characteristics and the static mechanical properties of wood-based composites verified preliminary findings. It was concluded that stress wave speed and attenuation could be used successfully to predict the static tensile and flexural properties of these materials. More importantly, it was possible to predict these properties at levels of accuracy previously considered unattainable. Additional study results are discussed. (Edited author abstracts)