Energy‐Based Failure Criterion for Wood

Abstract

Recent research into the strength of dimension lumber has led to the development of an alternative failure criterion based on the notion of a critical energy density for the material. The strength of wood is known to be related to the duration of an applied load; however, duration‐of‐load effects cannot be explained within the context of a theoretical failure criterion based solely on stress. Conversely, a theoretical relationship between ultimate stress and load duration can be demonstrated when an energy‐based failure criterion is combined with a viscoelastic stress‐strain model. In the present paper, the theoretical equations expressing the relationship between ultimate stress and load duration are derived for constant intensity loads. Two related energy‐based failure models are proposed and investigated. Using available experimental data as a reference, a numerical experiment is conducted to compare the two energy models with a widely used damage accumulation model.