Use of nondestructive techniques for determination of tension parallel-to-grain properties of spruce

Abstract

The paper presents a study of the tension properties of Irish-grown Sitka spruce. Fifty timber pieces were destructively tested having resonant frequency and knots measured. The aim was to improve knowledge of the performance of spruce in tension and to check the suitability of the equations given in the European standards to calculate secondary properties from grade determining properties. Static stiffness, whichlimited the grading of the dataset, was largely predicted using dynamic modulus of elasticity (MoEdyn). Tension strength was modelled using density and tKAR index. It was found also that adding MoEdyn in a linear regression was not useful. The research reveals that the equation given in EN384:2018 for tension strength, based on populations of higher stiffness than Irish spruce, results in values that may not be appropriate for Irish-grown spruce timber.