Effect of off-axis angle on tension failures of laminated moso bamboo- poplar veneer composites: An in situ characterization

Inspired by the natural gradient structure of the moso bamboo wall, a hybrid moso bamboo(B)Wood(W) veneer Composite (BWC) was developed with a specific structure of [B0o/ W90"/ B0o]. The dynamic fracture behaviors and damage mechanism of the BWC were characterized using in situ scanning electron microscopy. X-ray micro- computed tomography imaging was employed to verify the off-axis tensile mechanical properties. The results showed that the maximum tensile strength and modulus of the BWC under off-axis loadings were 232.25 MPa and 17.47 GPa, respectively. Meanwhile, the maximum specific strength and specific modulus of the BWC were 290.31 MPa center dot cm3 center dot g1 and 23.84 GPa center dot cm3 center dot g1, respectively, which are higher than both natural wood (95.26 MPa center dot cm3 center dot g1, 10.82 GPa center dot cm3 center dot g1), bamboo (208.56 MPa center dot cm3 center dot g1, 15.74 GPa center dot cm3 center dot g1) and even steel alloy (237.86 MPa center dot cm3 center dot g1, 21.98 GPa center dot cm3 center dot g1). Compared to reorganized bamboo (RB), the porosity of the BWC was 61.1% lower. The BWC was strengthened via internal toughening mechanisms (i.e. fiber bridging) and external toughening mechanisms (i.e. multiregional distribution of micro-cracks). This work highlights methods to design high-performance bio composite from commonly used biomaterials through synergistic strengthening and toughening mechanisms, which has significant advantages in the ever-growing construction industry. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).