Comparative Study of Destructive, Nondestructive, and Numerical Methods on the Determination of Moisture-Dependent Shear Moduli of Calabrian Pine

Abstract

In this study, the moisture-dependent shear moduli of Calabrian pine were determined by a 45° off-axis compression test, and ultrasonic measurement were performed to determine the effectiveness of the nondestructive method for shear modulus prediction. Also, finite element modeling and analysis was performed to compare the results with static stress-strain curves within the linear elastic region. Ultrasonic transverse wave velocities in longitudinal-radial (LR), longitudinal-tangential (LT), and radial-tangential (RT) planes decreased from 1447 to 1368, 1342 to 1264, and 682 to 642 m/s with an increase in relative humidity (RH) from 45% to 85%, respectively. Static and dynamic shear modulus in LR, LT, and RT planes decreased from 1054 to 933, 905 to 825, and 230 to 210 N/mm2, and 1141 to 1065, 982 to 909, and 254 to 235 N/mm2 when relative humidity increased from 45% to 85%, respectively. The influence of the moisture content on the transverse velocity and moduli was statistically significant. The coefficient of determination between the dynamic and static shear moduli ranged from 0.77 to 0.96.