MEASURMENT OF BENDING PROPERTIES OF RHIZOPHORA TROPICAL WOOD

Abstract

The Young’s modulus, load at the yield point and proportional limit stress from the compression bending (cb) test were compared with the four point bending tests (4pb). The theoretical Young’s modulus are larger than the real reading for 5mm and 10mm thick specimens, except for 200mm long specimens due to specimen nonlinearity. The experimental results for the short specimens are slightly high compared to the theory due to uniaxial compression in both tensile and compressive planes. Since the additional deflection produced by the shearing force and the stress concentration at the loading point was smaller with the compression bending test compared to the conventional four point bending test the values of Ecb are larger than E4pb. It is noted that when length/thickness (l/t)>80, the values of Ecb are scattered. In addition, Ecb decrease sharply when l/t<30. In order to obtain a stable Young’s modulus value, it is suggested that the l/t should be 30~80.

Keywords

• Young’s Modulus
• Proportional Limit Stress
• Compression Bending Test
• Four Point Bending Test
• Length to Thickness Ratio