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KAJI NUMERIK PENCEGAHAN PERTUMBUHAN RETAK DENGAN MENGGUNAKAN METODE MODIFIKASI BENTUK STOP-DRILLED HOLE (SDH) Dahlan, Hendery; Rusli, Meifal; Dwianda, Yudi
Media Mesin: Majalah Teknik Mesin Vol 18, No 2 (2017)
Publisher : Universitas Muhammadiyah Surakarta

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Abstract

ABSTRAK Salah satu mekanisme kegagalan yang utama dalam aplikasi teknik atau komponen mesin adalah penjalaran retak kelelahan. Penjalaran retak ini biasanya dimulai dari titik-titik pada daerah yang mengalami konsentrasi tegangan yang tinggi. Oleh karena itu salah satu metode untuk menghambat penjalaran retak adalah  mereduksi konsentrasi tegangan dimana salah satu metode yang digunakan adalah pemberian lubang di ujung retak atau dikenal dengan stop-drilled hole (SDH). Pada penelitian ini akan dikembangkan modifikasi bentuk model SDH. Pada dasarnya model yang dikembangkan ini adalah merubah bentuk pada sisi lubang agar tidak berbentuk lengkungan sehingga  konsentrasi tegangan menurun di daerah tersebut. Pemodelan lubang yang dikembangkan pada peneltian ini adalah penggambungan dua lubang dan tiga lubang pada ujung retak. Pada penelitian ini akan dilakukan penghitungan faktor konsentrasi tegangan untuk variasi jari-jari lubang yang diberikan. Dari penelitian yang telah dilakukan dapat disimpulkan bahwa pemberian dua lubang dan tiga lubang pada ujung cetak tersebut dapat mereduksi faktor konsentrasi tegangan dengan signifikan, nilai faktor konsentrasi tegangan antara dua lubang dan tiga lubang tidak berbeda signifikan terutama dengan meningkatnya nilai jari-jari lubang. Sementara itu, faktor konsentrasi tegangan tetinggi terjadi pada daerah perubahan geometri pada lubang untuk pemberian dua atau tiga lubang, akan tetapi faktor konsentrasi tegangannya masih cukup rendah jika dibandingkan dengan pemberian satu lubang. Kata Kunci : Konsentrasi Tegangan, Penjalaran Retak, Stop-Drilled Hole (SDH)   ABSTRACT One of the major failure mechanisms in engineering applications or machine components is the propagation of fatigue cracking. The spreading of these cracks usually are started from the points on the regions that are  experiencing high stress concentrations. Therefore, one of the method to inhibit this crack propagation is reducing the stress concentration in which one of the used methods  is the provision of a hole at the end of a crack or known as a stop-drilled hole (SDH). In this research will be developed  a modification form of SDH model. Basically the developed model is changing the shape on the hole side so there are not forming of the curve so that the stress concentration decreases in this area. The developed hole model in this research is the binding of two holes and three holes at the crack tip. This research will be calculated the stress concentration factor for variation of given hole radius. From the research that has been done, it can be concluded that the two holes and three holes on the tip of the crack can reduce the stress concentration factor significantly. Moreover,  the value of the stress concentration factor between two holes and three holes is not significantly different, especially with the increment of the hole radius. Meanwhile, the high stress concentration factor occured in the geometrical change area of the hole for two or three holes, but the stress concentration factor is still quite low when compared to the one hole. Keywords : Stress Concentration, Crack Propagation, Stop-Drilled Hole (SDH)
KAJI EKSPERIMETAL PENGHAMBAT PENJALARAN RETAK DENGAN MENGGUNAKAN PENGAKU Dahlan, Hendery; Dwianda, Yudi; Rusli, Meifal
Media Mesin: Majalah Teknik Mesin Vol 19, No 2 (2018)
Publisher : Universitas Muhammadiyah Surakarta

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Abstract

Salah satu penyebab retak muncul di struktur biasanya berawal pada daerah yang mengalami konsentrasi tegangan yang tinggi. Jika pembebanan terus dilakukan maka retak akan terus tumbuh dan menjalar sehingga menyebabkan terjadinya kegagalan. Oleh karena itu, diperlukan suatu cara atau metode yang efektif untuk menahan laju pertumbuhan retak sebelum kegagalan terjadi. Pada penelitian ini akan dilakukan kajian secara eksperimental pengaruh lasan, dimensi pengaku dan jumlah pengaku terhadap beban kritis sebelum retak menjalar. Dari penelitian yang telah dilakukan dapat disimpulkan bahwa pengaku yang diberikan sangat efektif mempengaruhi laju perambatan retak. Selain itu, dimensi pengaku mempengaruhi penghambatan penjalaran retak dimana semakin besar dimensi pengaku maka rata rata beban kritis yang dibutuhkan untuk retak mulai menjalar semakin besar. Sementara itu kualitaspengelasan pada retak sangat mempengaruhi penghambatan retak untuk menjalar.
Structural of Pedicle Screw on Biomechanical Characteristics of Spinal Scoliosis Correction Deformation Weriono, Weriono; Rusli, Meifal; Dahlan, Hendery; Sahputra, Roni Eka
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 69 No 1 (2025): 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 | DOI: 10.36842/jomase.v69i1.529

Abstract

Scoliosis correction methods often involve orthopedic procedures such as implant placement to stabilize movement and correct spinal deformity. The choice of surgical method is highly dependent on the location and nature of the fracture. Fractures with significant damage require a different approach compared to cases of minor injuries. Three dimensional finite element model of C1–L6 spine was used to simulate conditions with single cylindrical implant fixation under a vertical downward loading force 50 N and cylindrical screw types made of titanium alloy. The human spine, encompassing the cervical, thoracic, and lumbar regions, exhibits a complex biomechanical response when subjected to physiological loads. Displacement that occurs due to axial force can be the result of pedicle screw movement with vertebrae of the spine. Installation of 4 (four) rows of pedicle screws reduces the release of pedicle screws from the spine. The use of more fixation can reduce the stress distribution on the vertebrae of the spine.
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.
A Systematic Review on the Acoustic Performance of Nanocellulose-Modified Natural Fibers for Sound Insulation and Absorption Applications Muchlisinalahuddin; Rusli, Meifal; Dahlan, Hendery; Mahardika, Melbi
Piston: Journal of Technical Engineering Vol. 9 No. 1 (2025)
Publisher : Program Studi Teknik Mesin Universitas Pamulang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32493/pjte.v9i1.51526

Abstract

Noise pollution has become an increasingly concerning environmental issue, driving the development of sustainable acoustic materials as alternatives to conventional synthetic materials. This research conducts a systematic literature review on the acoustic effectiveness of natural fiber-based nanocellulose in sound isolation and absorption applications. The research method employs a qualitative approach with a comprehensive analysis of scientific publications from Scopus, Web of Science, ScienceDirect, and Google Scholar databases over the past ten years. The review results indicate that modification of natural fibers such as coconut coir, hemp fiber, banana pseudostem, and rice straw with nanocellulose at a concentration of 1-1.5% w/v is capable of improve sound absorption coefficients up to 0.7-0.9 in the 500-2000 Hz frequency range, comparable to synthetic materials such as fiberglass and mineral wool. This material demonstrates advantages in terms of dimensional stability improvement of 35-40%, lightweight density (150-300 kg/m³), balanced acoustic characteristics across a broad frequency spectrum, and biodegradable properties providing minimal environmental impact. The potential applications of this material are extensive in construction, automotive, and acoustic industries, with noise reduction capabilities of up to 8-12 dB. Despite facing challenges in raw material variability and production scalability, natural fiber and nanocellulose-based acoustic materials have promising prospects as sustainable solutions to global noise pollution problems with competitive performance against conventional materials.
Multi-Parameter Vibration Analysis for Bearing Fault Detection at Low Speeds Using Standard Accelerometers with Stud and Magnetic Mounting Noviandy, Noviandy; Rusli, Meifal
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 69 No 3 (2025): 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 | DOI: 10.36842/jomase.v69i3.559

Abstract

Detecting bearing defects at low rotational speeds remains a major challenge due to weak impulsive responses and dominant low-frequency components. This study evaluated the feasibility of using a standard industrial accelerometer (1 µA/ms², equivalent to 100 mV/g) for detecting outer race defects in bearings operating at 100–300 RPM. Experiments were conducted under both baseline and defected conditions using two mounting configurations: stud and magnetic. Vibration responses were analysed through overall values (velocity, acceleration, and shock pulse), spectral analysis, enveloped signals, and time waveform comparisons. Results show that standard accelerometers can effectively detect bearing defect signatures in low-speed machines (100–300 RPM), with diagnostic performance strongly influenced by the sensor mounting method. At 100 RPM, magnetic mounting occasionally recorded higher acceleration readings (?30%) due to uneven impulsive energy distribution and low-speed dynamic instability. At higher speeds (200–300 RPM), stud mounting produced stronger and more stable responses, with amplitudes about 2–8% higher than magnetic mounting, confirming its superior coupling rigidity. Spectral analysis alone was limited by broadband noise, while time waveform and envelope analyses revealed clearer defect-related impacts, particularly at 1× RPM and 2× BPFO. Overall, stud-mounted sensors demonstrated more consistent and reliable performance, validating their suitability for accurate and practical low-speed vibration monitoring.