An investigation of bamboo shear test methods and the influence of heat on bamboo shear strength

Abstract

The present study has been divided into two parts. At first, the different shear test methods mentioned in the ISO and ASTM Standards such as the direct shear test and the bowtie shear test were presented and compared to a method proposed by the authors so-called the interlaminar shear test method, to suggest an easy, reliable, and feasible way to measure the bamboo shear strength. At the interlaminar shear test method, a shear surface is created by using bamboo strips with two notches/cuts at two opposite sides. By changing the distance of the cuts and bamboo width, the variation of bamboo shear strength based on these two parameters was studied. The FEM modeling by ANSYS and the DIC (Digital Image Correlation) test were carried out to show the shear stress and strain variation alongside the shear surface of interlaminar samples. The different test methods show the results of direct and bowtie test methods are close to each other but different from the interlaminar test method. In conclusion, a comparison has been made between these three shear test methods. In the second part of this investigation, the interlaminar shear test method was chosen for the heat-treated samples. Shear tests were performed on specimens previously heated during either 3 or 24 h at each of six temperatures in the range of 100–225 °C. The first significant reduction in the shear strength was observed after heat treatment at 150 °C for 24 h and 175 °C for 3 h of heat exposure.