Eko Surojo
Sebelas Maret University

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Frictional Characterization Of Grey Cast Iron Train Brake Block Using A Reduced Scale Dynamometer Bernardus Prasetya Utama; Herru Santoso Budiono; Eko Surojo; Nurul Muhayat
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 1 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i1.48246

Abstract

The brake block is an important component that serves to slow down and stop the train. The safety of this transportation is very dependent on the reliability of this component. One of the important features of the brake block material is the coefficient of friction. The coefficient of friction of the brake block material must meet and match the requirements. The coefficient of friction of a material is measured using a friction test. Previous studies have shown that the friction coefficient of a material is influenced by braking conditions, namely contact pressure and friction speed. Many friction testing methods have been developed to study the characteristics of friction materials.  In contrast to previous studies, in this study, the frictional characteristics of gray cast iron brake blocks were evaluated using a reduced scale dynamometer. The friction test is carried out by pressing the brake block specimen to the surface of the rotating wheel. The specimen size of the brake block and carriage wheels is reduced to 1/4 of the original size. The friction test is carried out at a contact pressure of 0.15,  0.20, 0.25, and 0.30 (MPa) and the friction speeds of 3, 6, 9, and 12 (m/s). The results of this study indicate that the coefficient of friction of the gray cast iron brake block decreases with increasing friction speed and contact pressure.
The Effect of Fumigation and Alkalization on Dimensional Changes of Cantula Fiber Reinforced Unsaturated Polyester Composites Under Immersion M. Ihsan Tri Wibowo; Dody Ariawan; Eko Surojo
Mekanika: Majalah Ilmiah Mekanika Vol 21, No 1 (2022): MEKANIKA: Majalah Ilmiah Mekanika
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/mekanika.v21i1.49463

Abstract

This study aims to investigate effect of fumigation and alkaline treatment on dimensional change in cantula fibers reinforced UPRs composite under immersion test in aqueous environment. Composites were fabricated using compression moulding method with cantula fiber content of 30% vt with the addition of 5% microcrystalline cellulose. Composite specimens were immersed under aquades for 2 months at room temperature. The dimensional changes of cantula fiber reinforced UPRs in different solutions were found to follow a Fickian behavior. Fumigation treated fibers and alkali treated fiber composites after immersion has lower results both in dimensional changes and its slope than untreated fiber composites.