Research On Mechanical Properties And Elasticity Modulus Testing Methods Of Bamboo Engineering Material

This article researches on Mechanical properties and elastic modulus testing methods of glued laminated bamboo based on strips. The author conducts destructive tests to study characteristics of compressive mechanical properties of glued laminated bamboo included strength, deformation and failure mode in three different directions(grain, chord and redial). Modulus of elastic is been tested by nondestructive method of wave velocity and resonance, and also take influence factors into account covering slenderness ratio, density and so on. Conclusions of this study are as follows:1. The compressive strength decreases in grain, chord and radial directions. The strength in grain direction is three times of chordwise and radial directions’, and chordwise compressive strength is1.07times of redial’.2. The load-displacement curves of glued laminated bamboo shows significant elastoplasticity, and also different in each directions. The failure modes of glued laminated bamboo are different from bamboo’:in grain and chord directions, glue cracking leads to prematurely failure and with a sudden. Redial failure modes are different and related to slenderness ratio, when the ratio is small, failure occurs from side to the centre, bigger the ratio becomes, it will act shear failure.3. The MOE tested by ultrasonic and stress wave is bigger than it tested by static bending and both with measureable linear relationship (R2>0.5).The difference value between ultrasonic and bending is smaller than stress wave, and ultrasonic is of higher R2than stress wave. Therefore, ultrasonic and stress wave are feasible way to test MOE of glued laminated bamboo plate.4. Cantilever free transverse vibration is a better way to measure MOE and with higher correlation coefficient (R2>0.9) than both ultrasonic and stress wave. The ratio of length to height affects testing result, and if ratio bigger than30, the influence is negligible. Positive correlation is found by comparison between density and MOE tested by vibration.