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< 전시-P-18 > Viscoelastic properties of bamboo
( Wahyu Dwianto ),( Danang Sudarwoko Adi ),( Teguh Darmawan ),( Mohamad Gopar ),( Lisman Suryanegara ) 한국목재공학회 2018 한국목재공학회 학술발표논문집 Vol.2018 No.1
This study relates to measurement of the viscoelastic properties of bamboo to answer why bamboo is more easily bent than wood, whether this is related to its anatomical structure or its chemical components. To answer this question, static bending testing on the bamboo was done in dry, fresh, and after softening conditions. Andong (Gigantochloa pseudoarundinaceae (Steud.) Widjaja) bamboo which has potential as raw material of bamboo lamination was used in this experiments. For static bending tests, the bamboo internode was cut 30cm in length, 2cm in width and with varying thickness depending on the location of the internode on the stem (20 internodes/stem). Measurement results indicating that the diameter of the internode and its wall thickness decreases from the bottom to the top of internode. This causes moisture content of fresh bamboo decreases from the bottom to the top of internode. Modulus of rupture (MOR) increases, but its modulus of elasticity (MOE) decreases. This is due to the increased density towards the top of internode. Increased density is associated with anatomical structure, where in the top of internode, the portion of vascular bundles are greater than the parenchyma cells. Elastic limits, in-elastic limits, and maximum deflections before fracture is gradually decreases with different bamboo conditions from dry, fresh, and after softening. Anatomical structures will further observed from various curved radius after bent as well as the contents of chemical components analyzed to know the effect on softening condition of bamboo. Furthermore, the viscoelastic properties of bamboo will be compared with wood with the same density. However, it can be predicted that bamboo can be more easily bent because there are many parenchyma cells with thin-walled cells in the inner parts and more easily softened.
Rudi Hartono,Wahyu Hidayat,Imam Wahyudi,Fauzi Febrianto,Wahyu Dwianto,Jae Hyuk Jang,Nam Hun Kim 한국목재공학회 2016 목재공학 Vol.44 No.6
The objective of this study was to improve physical and mechanical properties of soft-inner part of oil palm trunk (S-OPT) after impregnation with phenol formaldehyde (PF) resin and densification by close system compression (CSC) method. Effect of different methods of PF resin impregnation (i.e., no vacuum-pressure, vacuum, and vacuum-pressure) was evaluated. The results showed that PF resin impregnation and CSC significantly improved the physical and mechanical properties of S-OPT up to: (1) 176% in density; (2) 309% in modulus of rupture (MOR); (3) 287% modulus of elasticity (MOE); and (4) 191% in the compressive strength. Physical and mechanical properties of S-OPT showed their best performances when PF resin impregnated with vacuum- pressure method as shown by higher weight gain, density, MOR, MOE, compressive strength, and lower recovery of set due to better penetration of PF resin into S-OPT. Combining PF resin impregnation and densification by CSC method could be a good method to improve physical and mechanical properties of S-OPT.
Quality Improvement of Oil Palm Trunk Properties by Close System Compression Method
Rudi Hartono,Imam Wahyudi,Fauzi Febrianto,Wahyu Dwianto,Wahyu Hidayat,Jae-hyuk Jang,Seung-hwan Lee,Se-hwi Park,Nam-hun Kim 한국목재공학회 2016 목재공학 Vol.44 No.2
Densification of the inner part of oil palm trunk (OPT) by the close system compression (CSC) method was performed in this study. The effects of the compression temperature and time on the anatomical, physical andmechanical properties of OPT were evaluated. The inner part of OPT with an initial average density of 0.3 g/cm3 was used as samples. Oven-dried samples were immersed in water and vacuumed until fully saturated and then compressed by CSC at 120, 140, 160 or 180℃ for 10, 20, 30 or 40 min. The anatomical characteristics of transverse and radial sections before and after compression were compared by optical microscopy. The physical and mechanical properties, including the density, recovery of set (RS), modulus of elasticity (MOE), modulus of rupture (MOR), and compression parallel to grain were examined. It was observed that the anatomical characteristic of the inner part of OPT (i.e., vascular bundles, vessels, and parenchyma tissue) became flattened, fractured, and collapsed after compression by CSC. The RS decreased with increasing compression temperature and time. The lower RS indicated high dimensional stability. The physical and mechanical properties (i.e., density, MOR, MOE, and compressive strength) of the inner part of OPT increased with increasing compression temperature and time. Compression by the CSC method at 160℃ for 40 min was the optimum treatment.