ABSTRACT

This paper derives analytical predictions for notched cross-laminated timber (CLT) plate delamination using fracture mechanics for crack propagation from the notch root. The analysis accounts for both CLT heterogeneity and residual stresses caused by seasonal variations in temperature and humidity. The accuracy of predictions coupled with shear corrections, was confirmed by comparison to finite element analysis. The fracture mechanics approach was validated as appropriate by comparison to recent experiments on notched CLT beams. Residual stress effects are significant and depend strongly on notch depth. Environmental changes that promote swelling, such as increases in temperature or moisture content, are more detrimental to plate integrity than are changes that promote shrinkage. Relatively modest levels of swelling stress can potentially cause spontaneous delamination. A new design guide for notched CLT plates that includes effects of heterogeneity and residual stresses is proposed.

摘要

本文使用断裂力学从缺口根部进行裂纹扩展，推导出缺口交叉层压木材 (CLT) 板分层的分析预测。该分析考虑了由温度和湿度的季节性变化引起的 CLT 异质性和残余应力。通过与有限元分析的比较，证实了预测的准确性以及剪切校正。通过与最近在缺口 CLT 梁上的实验进行比较，断裂力学方法得到了适当的验证。残余应力的影响很显着，并且很大程度上取决于凹槽深度。促进膨胀的环境变化，例如温度或水分含量的增加，比促进收缩的变化对板材完整性的危害更大。相对适度的膨胀应力水平可能会导致自发分层。提出了一种包括异质性和残余应力影响的带缺口 CLT 板的新设计指南。