Hao Jingxin, Wu Xinfeng, Oporto Gloria, Wang Jingxin, Dahle Gregory, Nan Nan
College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
Division of Forestry and Natural Resources, West Virginia University, Morgantown, WV 26506, USA.
Materials (Basel). 2018 Nov 19;11(11):2325. doi: 10.3390/ma11112325.
A new type of Taiji honeycomb structure bonded outside with wood-based laminates was characterized from a mechanical standpoint. Both theoretical and experimental methods were employed to analyze comprehensively the deformation behavior and failure mechanism under a three-point bending test. The analytical analysis reveals that a Taiji honeycomb has 3.5 times higher strength in compression and 3.44 times higher strength in shear compared with a traditional hexagonal honeycomb. Considering the strength-weight issue, the novel structure also displays an increase in compression strength of 1.75 times and shear strength of 1.72 times. Under a three-point bending test, indentation and core shear failure played the dominant role for the total failure of a wooden sandwich with Taiji honeycomb core. Typical face yield was not observed due to limited thickness-span ratio of specimens. Large spans weaken the loading level due to the contribution of global bending stress in the compressive skin to indentation failure. A set of analytical equations between mechanical properties and key structure parameters were developed to accurately predict the threshold stresses corresponding to the onset of those deformation events, which offer critical new knowledge for the rational structure design of wooden sandwich composites.
从力学角度对一种新型的外部粘结木质层压板的太极蜂窝结构进行了表征。采用理论和实验方法对三点弯曲试验下的变形行为和破坏机理进行了综合分析。分析表明，与传统六边形蜂窝相比，太极蜂窝的抗压强度高3.5倍，抗剪强度高3.44倍。考虑强度-重量问题，这种新型结构的抗压强度提高了1.75倍，抗剪强度提高了1.72倍。在三点弯曲试验中，压痕和芯部剪切破坏是导致带有太极蜂窝芯的木质夹层结构整体破坏的主要因素。由于试样的厚度-跨度比有限，未观察到典型的面板屈服现象。由于压缩面板中的整体弯曲应力对压痕破坏的影响，大跨度会削弱加载水平。建立了一组力学性能与关键结构参数之间的解析方程，以准确预测这些变形事件开始时对应的阈值应力，这为木质夹层复合材料的合理结构设计提供了重要的新知识。
