Comparing the effectiveness of three acoustic emission procedures for predicting strengths of finger-joints from tropical African hardwoods

Stress at first acoustic emission event-count, as well as cumulative event-count at 80 percent of mean failure stress and cumulative event-count at 80 percent of mean proportional limit stress were separately regressed on strengths of finger-joints from Obeche (Triplochiton scleroxylon), Makore (Tieghemella heckelii) and Moabi (Baillonella toxisperma). The regression suggested that all the three acoustic emission properties could be used to non-destructively predict the ultimate tensile and bending strengths of finger-joints from the three hardwoods. However, stress at first event-count seemed most suitable for predicting ultimate tensile strength of finger-joints from the three species, whilst cumulative event-count at 80 percent of mean failure stress seemed best for modulus of rupture. Correlation coefficients obtained for the prediction models developed were, generally, good and statistically significant (Ø = 0.05).