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Effects of a Longitudinal Crack in Overhung Rotor Malta, Jhon; Bur, Mulyadi; Fadillah, Muhammad Rahmanda
Andalasian International Journal of Applied Science, Engineering and Technology Vol. 2 No. 1 (2022): March 2022
Publisher : LPPM Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/aijaset.v2i1.33

Abstract

In this study, a longitudinal crack simulation will be carried out on the shaft using the MSC Nastran/Patran to identify the effect of variations in the depth and length of the crack on the shaft on the stress distribution along the shaft and to determine the dynamic behavior of the rotor shaft overhung system due to cracks. The simulation was carried out with two models, with and without a crack. The first crack position locates between the disk and the bearing, and the second is between the two supports. Based on the simulation test results, the natural frequencies tend to decrease with increasing variations in the depth and length of the crack, especially at first and second natural frequencies. The cracks between the disc and the bearing significantly reduce stiffness than the cracks between the two supports. Furthermore, in the stress analysis, the cracks increase the rotor's maximum stress, which occurs in the area of the ultimate bending moment.
The Reduction of Stress Concentration at a Crack Tip Using Multi Stop-Drilled Hole (MSDH) Dahlan, Hendery; Rusli, Meifal; Bur, Mulyadi
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 55 No 1 (2018): Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)
Publisher : International Society of Ocean, Mechanical and Aerospace -scientists and engineers- (ISOMAse)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (837.459 KB) | DOI: 10.36842/jomase.v55i1.54

Abstract

A new shape of stop-drilled hole is proposed in which triple stop-drilled holes called Multi Stop Drilled Hole (MSDH) are drilling at the crack tip. The main objective of the proposing method is to reduce stress concentration at the edge of the stop holes. Reducing the stress concentration factor at the crack tip is the main issue to arrest the crack growth. In this study, a numerical methodology using finite element analysis with linear elastic behaviour assumption is considered to study the effect of the stop-drilled hole on the reduction of stress concentration at crack tip. The variation number of stop-drilled hole and hole diameter at the crack tip corresponding to the stress concentration will be investigated. It reveals that the number of stop-drilled holes significantly influenced to reduce the stress concentration factor. Increasing the number of the stop-drilled holes will reduce the stress concentration factor. Furthermore, the diameter of stop hole significantly affects the decreasing stress concentration. The increasing value diameter of the stop-drilled hole will reduce the stress concentration. In the meantime, the triple-drilled hole has the highest percentages of decreasing stress concentration and the lowest stress concentration comparing to single and double stop-drilled hole.
Effects of a Longitudinal Crack in Overhung Rotor Malta, Jhon; Bur, Mulyadi; Fadillah, Muhammad Rahmanda
Andalasian International Journal of Applied Science, Engineering and Technology Vol. 2 No. 1 (2022): March 2022
Publisher : LPPM Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/aijaset.v2i1.33

Abstract

In this study, a longitudinal crack simulation will be carried out on the shaft using the MSC Nastran/Patran to identify the effect of variations in the depth and length of the crack on the shaft on the stress distribution along the shaft and to determine the dynamic behavior of the rotor shaft overhung system due to cracks. The simulation was carried out with two models, with and without a crack. The first crack position locates between the disk and the bearing, and the second is between the two supports. Based on the simulation test results, the natural frequencies tend to decrease with increasing variations in the depth and length of the crack, especially at first and second natural frequencies. The cracks between the disc and the bearing significantly reduce stiffness than the cracks between the two supports. Furthermore, in the stress analysis, the cracks increase the rotor's maximum stress, which occurs in the area of the ultimate bending moment.