Rescalvo Francisco J, Timbolmas Cristian, Bravo Rafael, Gallego Antolino
Building Engineering School, University of Granada, 18071 Granada, Spain.
Department of Structural Mechanics, University of Granada, 18071 Granada, Spain.
Materials (Basel). 2020 Jul 14;13(14):3134. doi: 10.3390/ma13143134.
The structural use of timber coming from fast growing and low-grade species such as poplar is one of the current challenges in the wood value chains, through the development of engineering products. In this work, a qualitative comparison of the behavior of mixed glued laminated timber made of pine in their outer layers and of poplar in their inner layers is shown and discussed. Single-species poplar and pine laminated timber have been used as control layouts. The investigation includes destructive four-point bending tests and three non-destructive methodologies: finite elements numerical model; semi-analytical model based on the Parallel Axes theorem and acoustic resonance testing. An excellent agreement between experimental and numerical results is obtained. Although few number of samples have been tested, the results indicate that the use of poplar as a low-grade species in the inner layers of the laminated timber can be a promising technology to decrease the weight of the timber maintaining the good mechanical properties of pine. Likewise, the need for the use of the shear modulus in both experimental measurements and numerical analysis is suggested, as well as the need to reformulate the vibration methodology for non-destructive grading in the case of mixed timber.
通过开发工程产品，将速生低质树种（如杨树）的木材用于结构用途是当前木材价值链面临的挑战之一。在这项工作中，展示并讨论了外层为松木、内层为杨树的混合胶合层压木材性能的定性比较。单树种杨树和松木制层压木材已用作对照布局。研究包括破坏性四点弯曲试验和三种非破坏性方法：有限元数值模型；基于平行轴定理的半解析模型以及声共振测试。实验结果与数值结果取得了极佳的一致性。尽管测试的样本数量较少，但结果表明，在层压木材内层使用杨树这种低质树种可能是一种很有前景的技术，既能减轻木材重量，又能保持松木良好的机械性能。同样，建议在实验测量和数值分析中都使用剪切模量，以及在混合木材的情况下重新制定用于无损分级的振动方法。
