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Journal : Teknomekanik

Stability Study of Flat Hull Ship for Fishing Tourism Nabawi, Rahmat Azis; Syahril, Syahril; Salmat, Salmat
Teknomekanik Vol. 3 No. 2 (2020): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (205.328 KB) | DOI: 10.24036/teknomekanik.v3i2.9272

Abstract

The availability of boats is needed to develop fishing tourism. Most of the boats used so far generally use fishing boats made of woodcut in the forest, so this can damage the environment and cause natural disasters. Ships using a flat plate hull made of steel can be a substitute for wooden ships. This study aims to test the stability of a flat plate vessel designed for fishing boats. The ship stability test was carried out using a computer simulation method using Maxsurf Stability software. The ship stability criteria refer to the International Maritime Organization code A.749 (18), Ch 3-design criteria applicable to all ships. The ship stability analysis was carried out on two variations of the load case. The value of GZ at A h 300, A h 400 and A h 300 - A h 400 for load case 1 and 2 are greater than the minimum standards determined by IMO. The maximum GZ value at load case 1 occurs at an angle of 400 and at load case 2 at an angle of 60.90. The GM value in load case 1 is 0.609 meters and in load case 2 is 0.485 meters. Based on the results of the tests that have been carried out, it can be denied that the flatboat design model for fishing tourism meets the criteria set by the International Maritime Organization.
Loading-dependent mechanical performance of alkali-treated areca nut husk fiber reinforced polyester composites modified with Uncaria gambir extract Nabawi, Rahmat Azis; Syahril, Syahril; Abral, Hairul
Teknomekanik Vol. 8 No. 2 (2025): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v8i2.52472

Abstract

Natural fiber-reinforced polymer composites often experience mechanical performance limitations due to weak interfacial bonds between hydrophilic fibers and hydrophobic matrices. This study experimentally examined the effect of alkali treatment and modification using Uncaria gambir extract (UGE) on the mechanical properties and interface morphology of polyester composites reinforced with areca nut husk fiber (ANHF). Four composite configurations were prepared with a constant fiber weight fraction of 40 wt.% after alkali treatment using 6% NaOH for 24 hours, while the remaining 2 wt.% UGE was selectively applied as a fiber surface treatment, matrix additive, or a combination of both. Tensile and flexural properties were evaluated in accordance with ASTM standards, while interface morphology was examined using scanning electron microscopy (SEM). The results showed that alkali-treated composites without UGE addition had the highest tensile strength, which was attributed to increased fiber surface roughness and mechanical interlocking mechanisms. Conversely, fiber surface modification using UGE significantly increased flexural strength, indicating better stress distribution under flexural loading due to increased interface continuity. However, the addition of UGE to the matrix caused a decrease in tensile strength, which was thought to be related to a reduction in matrix stiffness. SEM observations confirm the presence of distinct interface morphology differences according to the treatment applied. These findings indicate that UGE serves primarily as a bio-based interfacial modifier, enhancing flexural performance, while its effectiveness is strongly governed by the mechanical loading mode.