Non-destructive vibration assessment in structural elements of native Amazonian wood

Non-destructive testing (NDT) techniques have gained prominence in structural engineering due to their practicality and efficiency. Among these, vibration-based methods estimate the dynamic modulus of elasticity (MOE) of wood elements using their natural frequency. However, because this approach relies on the propagation of mechanical waves, the estimated values can be affected by specimen dimensions, internal discontinuities, and anatomical characteristics of the species. This study aimed to evaluate the applicability of these methods for estimating MOE in structural-size elements ( n = 60) of four tropical Amazonian species: Trattinickia burseraefolia (Breu sucuruba), Sclerolobium paraensis (Tachi branco), Sclerolobium melinonii (Tachi preto) and Vatairea paraensis (Fava amargosa). Specimens were tested according to the standardised static bending (SB) methodology, used as a reference, and by longitudinal (LV) and transverse (TV) vibration NDT. Results indicated systematic deviations, LV tended to overestimate the expected values, whereas TV underestimated them, with larger discrepancies observed in stiffer species. Pearson's correlations showed the best agreement with SB when the four species were analysed as a single dataset ( r = 0.936 for TV and r = 0.973 for LV). Correction equations were proposed through linear regression analysis, resulting in high coefficients of determination ( R 2 ), 91.01% and 97.67% for predicting MOE SB values using TV and LV tests, respectively. Therefore, vibration-based methods demonstrated good applicability in structural-size elements of native tropical hardwoods, however, their results should be corrected using appropriate models.