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Analisis Tegangan pada Belokan Pipa Marine Boil Off Gas (MaBOG) Berbasis Metode Elemen Hingga Rudi Kurniawan; Arhami Arhami; Rahmatsyah Maksum Ramsi
Jurnal Teknik Mesin Unsyiah Vol 6, No 2 (2018)
Publisher : Jurnal Teknik Mesin Unsyiah

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24815/jtm.v6i2.18231

This paper discusses the stress analysis of marine boil off gas pipe elbow. The piping system receives several loading conditions such as expansion load, occasional load, operation load, and sustain load, which are referred to as static loading conditions. As a result of the load conditions can be known stress distribution and examine the strength of the weld connection on the pipe elbow. The purpose of this research is to know the distribution of stress at the elbow of the pipe due to static loading conditions. The method used in this study using finite element analysis. The result of stress simulation in pipe elbow is 771 Pa and the result of calculation of stress in pipe elbow is 3,94 Pa. The result of piping system simulation shows the value of the pipe elbow e due to the load operation of 23151,34 kPa, the sustain load is 24918,91 kPa, the occasional load is 59110,83 and the expansion load does not produce the stress value. From the results of the analysis, the stress due to operating, sustain, and expansion loads are categorized as safe because they do not exceed the allowable stress values of each loading condition.

The Analysis of Loosening of Bolt Connection Due to Structural Vibration Through Changes in Dynamic Characteristics Rahmatsyah Maksum Ramsi; Meifal Rusli; Mulyadi Bur
Jurnal Teknik Mesin Vol 16 No 1 (2023): Jurnal Teknik Mesin
Publisher : Politeknik Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30630/jtm.16.1.1091

Bolted joints are generally used to connect two or more mechanical structures due to their ease of assembly and disassembly for maintenance. However, the problem of vibration is one of the main challenges when the tightness of the bolted joints is insufficient, causing failures such as looseness and resulting in disconnection. Looseness is the most common cause of dynamically loaded bolted joint structure failure. This study tested a simple bolt joint structure to observe the looseness indication of the bolt joint after it was vibrated using a shaker in a single-frequency excitation. A freely fixed beam consisting of two beams connected by a bolt and subjected to varying bolt tightening torques. Then the response measurement is carried out by recording the FRF graph obtained from loosening and tightening bolt torque effects. Modal parameters such as personal frequency and damping ratio were collected through experimental modal analysis (EMA). It was found that the structure’s vibration could change the conditions of loosening or lower tightening torque indicated by shifting the structure’s natural frequency. In addition, the damping characteristics are also affected by changes in the tightening torque. Especially when conditions are loose, the damping ratio becomes much higher than that of tightening.

Bolted Joint Loosening Analysis Due to Structural Vibrations using Short-Time Fourier Transform and Wavelet Transform Rahmatsyah Maksum Ramsi; Meifal Rusli; Feblil Huda
METAL: Jurnal Sistem Mekanik dan Termal Vol. 9 No. 2 (2025): Jurnal Sistem Mekanik dan Termal (METAL)
Publisher : Department of Mechanical Engineering, Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/metal.9.2.130-138.2025

This research investigates the influence of bolt loosening on the dynamic behavior of a steel beam structure under continuous vibration excitation for 30 minutes. Bolted joints play a critical role in maintaining structural integrity; however, loosening caused by vibration remains one of the most common failure mechanisms in mechanical structures. To capture the effect of bolt loosening, acceleration responses were analyzed using time-domain inspection, Fast Fourier Transform (FFT), Short-Time Fourier Transform (STFT), and Continuous Wavelet Transform (CWT). The experimental setup involved controlled vibration excitation applied to a steel beam with bolted connections, and response signals were recorded at different stages of loosening progression. The time-domain analysis showed a gradual reduction in acceleration amplitude as bolt tightness decreased, indicating energy dissipation and stiffness loss. FFT provided an overview of frequency content but lacked sensitivity to localized variations. STFT and CWT enabled a more detailed examination of the time-frequency domain, revealing a loss of high-frequency components and significant redistribution of energy patterns during the loosening process. Both methods successfully identified shifts in natural frequencies and variations in response amplitude. Especially, CWT exhibited superior resolution in detecting early-stage loosening compared to STFT, making it more effective for practical monitoring applications. These results highlight the potential of time-frequency analysis as a diagnostic tool for vibration-based Structural Health Monitoring (SHM) systems. Early detection of bolt loosening through non-destructive vibration analysis can improve safety, reduce maintenance costs, and extend the service life of mechanical structures.

Analysis of bolted joint loosening due to structural vibrations using short-time fourier transform and wavelet transform Ramsi, Rahmatsyah Maksum
Prosiding SNTTM Vol 23 No 1 (2025): SNTTM XXIII October 2025
Publisher : BKS-TM Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.71452/3wteep54

This research investigates the influence of bolt loosening on the dynamic behavior of a steel beam structure under continuous vibration excitation for 30 minutes. Bolted joints play a critical role in maintaining structural integrity; however, loosening caused by vibration remains one of the most common failure mechanisms in mechanical structures. To capture the effect of bolt loosening, acceleration responses were analyzed using time-domain inspection, Fast Fourier Transform (FFT), Short-Time Fourier Transform (STFT), and Continuous Wavelet Transform (CWT). The experimental setup involved controlled vibration excitation applied to a steel beam with bolted connections, and response signals were recorded at different stages of loosening progression. The time-domain analysis showed a gradual reduction in acceleration amplitude as bolt tightness decreased, indicating energy dissipation and stiffness loss. FFT provided an overview of frequency content but lacked sensitivity to localized variations. STFT and CWT enabled a more detailed examination of the time-frequency domain, revealing a loss of high-frequency components and significant redistribution of energy patterns during the loosening process. Both methods successfully identified shifts in natural frequencies and variations in response amplitude. Especially, CWT exhibited superior resolution in detecting early-stage loosening compared to STFT, making it more effective for practical monitoring applications. These results highlight the potential of time-frequency analysis as a diagnostic tool for vibration-based Structural Health Monitoring (SHM) systems. Early detection of bolt loosening through non-destructive vibration analysis can improve safety, reduce maintenance costs, and extend the service life of mechanical structures.

Residential AC Technician Competency Training and Certification (Level 3) in Pekanbaru Brian Agung Cahyo P.; Sunny Ineza Putri; Jheri Hermanto; Anita Susilawati; Dedy Masnur; Dodi Sofyan Arief; Putri Nawangsari; Annisa Wulan Sari; Mintarto .; Hanif Nugroho Aji; Rahmatsyah Maksum Ramsi
JURNAL TEPAT : Teknologi Terapan untuk Pengabdian Masyarakat Vol 9 No 1 (2026): Environmental-based Awareness for Agile Community Strength
Publisher : Faculty of Engineering UNHAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25042/jurnal_tepat.v9i1.687

This Community Service Activity by the Mechanical Engineering Department of Riau University was a strategic move to address the urgent need for the formalization and quality improvement of Air Conditioner (AC) technicians. The program was based on the official appointment of Mechanical Engineering Unri as a Temporary Competency Test Center by a credible Professional Certification Body (LSP), affirming the institution's role in implementing the National Work Competency Standards (SKKNI). Targeting technicians with a minimum of one year of experience, the program had a dual objective: validating the existing practical skills while enhancing knowledge on crucial aspects like Occupational Health and Safety (K3) and environmentally compliant refrigerant handling. The PKM was implemented through structured stages, commencing with strict recruitment and selection, followed by comprehensive training delivered by Unri's competent lecturers, focusing on core competency units. The culmination was the Competency Test, conducted independently by certified Assessors from the partner LSP at the Unri TUK. The assessors evaluated participants' knowledge, skills, and work attitude through written, oral, and practical examinations. The main outcome of this activity was the successful certification of professional technicians. A total of 10 (ten) AC technicians were declared Competent and officially received the AC Technician Professional Competency Certificate from BNSP. This achievement significantly contributes to upgrading the quality and competitiveness of the local workforce, boosting professionalism, service quality, and career prospects for the certified technicians.

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