Assessing modulus of elasticity of wood-fiber cement (WFC) sheets using nondestructive evaluation (NDE)

This study evaluates whether the mechanical properties of modulus of ruptur e (MOR) and modulus of elasticity (MOE) of wood-fiber cement (WFC) sheets a re correlated with the nondestructive parameters of stress wave velocity an d density of the material. Longitudinal stress wave technique was used to e valuate WFC nondestructively using a total of 117 specimens (measuring each 241 x 51 mm) obtained from 39 WFC sheets. The aim was to establish the cor relation between dynamic versus static MOE of the material for predicting t he actual mechanical property. Even though short dimension specimens were u sed, results obtained were encouraging. A correlation coefficient (R) of 0. 828 was found when the static MOE of the material was used as a function of nondestructive parameters. A multivariate linear regression analysis using the specimen's density, wave velocity, and dynamic MOE provided the strong est correlation to the static MOE. The correlation observed for MOR as a fu nction of static MOE is within the normal range obtained for wood composite s. A nondestructive evaluation (NDE) using full size WFC sheets is recommen ded and can probably improve the relationship between the static and the pr edicted MOE. (C) 2001 Elsevier Science Ltd. All rights reserved.