The effect of immersion with time and water variations on bending strength of malapoga wood (Toona Ciliata M. Roem)

Mechanical Engineering, Tadulako University, 94118 Palu, Indonesia

^* Corresponding author : awsyahrani_untad@yahoo.com

Abstract

Bending strength is a parameter used in wood structure planning. The purpose of this study was to determine the effect of time and water of immersion on increasing bending strength. The main ingredient of this research is malapoga wood (Toona Ciliata M. Roem) which was previously preserved by immersion with brackish water, sea water and river for 2,4,6 and 8 weeks. Bending strength specimen and testing procedure refer to ASTM D14. A cross section of the test specimen is then subjected to a macro photograph to determine its failure mechanism. The test results show that Immersion using river water gives a greater bending strength value followed by using brackish water and sea water. The maximum bending strength of the river water is 26. 64 MPa at the time of immersion 4 weeks later followed by brackish water at 25. 86 MPa while the maximum bending strength value of seawater occurs in immersion for 6 weeks which is 24. 52 MPa. The immersion time causes the malapoga wood to become denser due to all the cavities in the malapoga wood filled with material contained in brackish water, sea and river so that the fibers of malapoga wood close up, dry out and crystallize inside the malapoga wood cavity which causes the bending strength of malapoga to increase.