Static flexural behavior of bamboo as a functionally graded material and the effect of heat on dynamic flexural modulus

Abstract

The objective of the present investigation is to study the static and dynamic flexural behavior of bamboo as a functionally graded material to determine the Static Flexural Modulus (SFM) for untreated bamboo samples and to evaluate the effect of heat on the variation of the Dynamic Flexural Modulus (DFM). For the static flexural test, initially, the image processing has been carried out to establish the fiber distribution equation along the radial direction followed by the use to measure the tensile and compressive modulus of elasticity (MOE). The result of static flexural tests shows four different values of MOE at tensile and compressive state for inner and outer bamboo walls with low and high fiber density respectively. The average of the MOE at the tensile is circa 12% higher than in its compressive state. A non-destructive method, based on the impulse excitation technique is proposed for the heat-treated specimens to establish the DFM. The effects of different temperatures and time exposures as well as moisture content, on the DFM and weight of the specimens, have been considered in this study. Comparing the static and dynamic test results for untreated bamboo does not show a meaningful difference between SFM and DFM. The dynamic flexural test shows the effect of heat treatment on DFM to be less than 6% when heated for 3 h at 200 °C or when heated at 175 °C for 24 h.