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All Journal Jurnal Rekayasa Mesin Scientific Journal of Mechanical Engineering Kinematika AMMA : Jurnal Pengabdian Masyarakat Journal of Mechanical Engineering and Applied Technology Journal of Mechanical Engineering and Fabrication
Elfrida Rizky Riadini
Politeknik Negeri Semarang
Humanities Automotive Engineering Chemistry Control & Systems Engineering Energy Engineering Industrial & Manufacturing Engineering Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mechanical Engineering Nursing

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Analisa Numerik Pengaruh Karakteristik Gelombang Air Laut pada Wave Energy Converter Tipe Bottom Hinge Menggunakan Metode Smoothed Particles Hydrodynamics An Nizhami, Avicenna; Riadini, Elfrida Rizky
Jurnal Rekayasa Mesin Vol 16, No 1 (2021): Volume 16, Nomor 1, April 2021
Publisher : Mechanical Engineering Department - Semarang State Polytechnic

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jrm.v16i1.2472

Abstract

Energi terbarukan yang bersumber dari gelombang air laut  menjadi dasar penelitian ini. Penelitian ini bertujuan untuk menganalisa Wave Energy Converter (WEC) tipe bottom hinge menggunakan metode numerik Smoothed Particle Hydrodynamics (SPH). Dinamika gerak dari WEC didekati dengan persaman getaran torsional dengan memodelkan generator sebagai spring dan damper. Pada metode SPH domain penelitian didiskritkan menjadi partikel yang merepresentasikan partikel fluida dan partikel solid. Persamaan atur yang digunakan adalah konservasi massa dan momentum. Validasi menunjukkan bahwa metode SPH dapat dengan akurat meprediksi dinamika gelombang air laut. Gaya hidrodinamis dan energi yang dihasilkan oleh WEC mempunyai nilai yang fluktuatif namun dengan pola yang periodik.
Solar radiation monitoring system for electric vehicle charging using solar modules based on the Internet of Things Herlambang, Yusuf Dewantoro; Huda, Muhamad Nurul; Antoro, Daffa Yudha Akbar Putra; Ghozali, Hanif Faizal; Setyawan, Martando Robby; Apriandi, Nanang Apriandi; An-Nizhami, Avicenna; Yanuar, Padang; Riadini, Elfrida Rizky; Marliyati, Marliyati
Journal of Mechanical Engineering and Fabrication Vol. 2 No. 1 (2025): Maret
Publisher : Journal of Mechafa Engineering and Fabrication

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.64273/jmef.v2i1.17

Abstract

The utilization of solar energy to support electric vehicle charging still faces challenges related to efficiency and real-time solar radiation monitoring. Addressing this issue is critical given the importance of optimizing renewable energy to facilitate the transition toward sustainable transportation. This study offers a solution through the development of an Internet of Things (IoT)--based solar radiation monitoring system capable of measuring solar light intensity in real time. The system employs a BH1750 sensor integrated with an ESP32 microcontroller to process data, transmit it to the Firebase Realtime Database, and display it via an Android application. The methodology encompasses the design, implementation, and testing of the system on an electric vehicle placed in an open area for 10 hours of observation. Results indicate that the highest light intensity, recorded at 98,321 lux, corresponded to solar radiation of 776.74 W/m², while the lowest light intensity, 69 lux, resulted in radiation of 0.55 W/m². The implications of this research include enhanced efficiency in electric vehicle charging, the advancement of IoT-based solar energy systems, and the potential integration with energy storage technologies and predictive algorithms to improve energy sustainability.
Experimental and Numerical Study of Shock Absorber Characterization and The Implication on The Dynamics of Half Vehicle Suspension System Model An-Nizhami, Avicenna; Sriyanto, Nanang Budi; Sumiyarso, Bambang; Ulum, Showi Nailul; Riadini, Elfrida Rizky; Widodo, Ignatius Gunawan
Jurnal Rekayasa Mesin Vol. 18 No. 3 (2023): Volume 18, Nomor 3, Desember 2023
Publisher : Mechanical Engineering Department - Semarang State Polytechnic

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jrm.v18i3.5023

Abstract

This study aimed to characterized shock absorber damping for passenger comfort. The riding comfort of the vehicle has direct correlation to the damping characteristic of the shock absorber of the suspension system. Two different shock absorbers were experimentally evaluated, and their damping characteristics were integrated into a half-car model to study the vehicle's dynamic response to harmonic road disturbances. The investigation involved numerical simulations of the half-car model subjected to harmonic road disturbances, represented by a set of ordinary differential equations solved using the Dormand-Prince method. Experimental data yielded average damping forces of 502.77 N for shock-absorber #1 and 192.03 N for shock-absorber #2. Calculations resulted in damping coefficients of 3888.57 N ·s/m for shock-absorber #1 and 1397.85 N ·s/m for shock-absorber #2, with corresponding damping ratios of 0.29 and 0.105. These damping ratios generally aligned with typical values for passenger car shock absorbers, except for shock-absorber #2, which deviated from the expected range. The study found that at 60 km/h and 90 km/h, shock-absorber #1 with ζ=0.29 exhibited superior performance in reducing displacement amplitude compared to shock-absorber #2 at ζ=0.105. However, at 120 km/h, both shock-absorbers displayed similar responses, with shock-absorber #1 slightly surpassing shock-absorber #2 in displacement amplitude.
Mass Ratio Influence on Vortex-Induced Vibration of a Flexible Cylinder using Large Eddy Simulation at Re=1000 An-Nizhami, Avicenna; Apriandi, Nanang; Setiawan, Trio; Kristiawan, Timotius Anggit; Riadini, Elfrida Rizky; Janitra, Atikah Ayu; Yanuar, Padang
Journal of Mechanical Engineering and Applied Technology Vol. 2 No. 1 (2024): VOLUME 2 ISSUE 1 YEAR 2024 (MARCH 2024)
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jmeat.v2i1.5498

Abstract

The study investigates the phenomenon of vortex-induced vibration (VIV) using Large Eddy Simulation (LES) at a Reynolds number of 1000, focusing on transitional flow conditions. LES has proven effective in understanding VIV across Reynolds number regimes, aiding in comprehending flow physics and mechanisms behind VIV. The research aims to contribute data for validating numerical models and informing engineering practices. The study employs the Navier-Stokes equation and the continuity equation to analyze fluid flow, treating it as incompressible due to negligible density changes. The three-dimensional incompressible momentum equation is discretized using the finite volume method within the spatial domain. Resolution of the pressure Poisson equation ensures compliance with free divergence conditions, enhancing computational fluid dynamics simulations' reliability. Validation of the fluid flow solver involves comparing computed drag force coefficients with established benchmarks, showing agreement within small discrepancies. The study delves into vibration behavior induced by cross flow at various reduced velocities (), noting distinct patterns ranging from irregularities at low  to quasi-periodic behavior at higher values. Analysis of maximum cylinder displacement () across different reduced velocities and mass ratios underscores the complex relationship between system parameters and displacement dynamics. A consistent occurrence of y_max at a specific reduced velocity highlights its significance, while varying mass ratios affect displacement patterns, indicating the importance of understanding these dynamics for optimizing fluid-structure interaction systems.
Two-Degree-of-Freedom Flow-Induced Vibrations of an Elastically-Mounted Cylinder under Oscillatory Flow: A Numerical Study Riadini, Elfrida Rizky; An-Nizhami, Avicenna; Yanuar, Padang; Yobioktabera, Amran; Lathief, Muttabik Fathul
Jurnal Rekayasa Mesin Vol. 20 No. 3 (2025): Volume 20, Nomor 3, Desember 2025
Publisher : Mechanical Engineering Department - Semarang State Polytechnic

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jrm.v20i3.7102

Abstract

Flow-Induced Vibration (FIV) in oscillatory flow represents a complex fluid–structure interaction that remains insufficiently explored, particularly for two-degree-of-freedom (2-DoF) systems allowing coupled inline and cross-flow motion. Previous studies have primarily focused on steady flows or limited parameter ranges, leaving a significant knowledge gap in understanding dynamic responses influenced by both reduced velocity ( ) and Keulegan–Carpenter (KC) numbers. This study aims to numerically investigate the vibration characteristics of a 2-DoF circular cylinder subjected to oscillatory flow, emphasizing the coupling mechanism between the two motion directions under varying  and KC values. The research employed a numerical approach based on the Direct Forcing Immersed Boundary (DFIB) method integrated with Navier–Stokes solvers and structural motion equations. Simulations were conducted for KC values of 5–20 and  ranges between 5–35. The temporal integration was performed using the third-order Adams–Bashforth schemes to ensure accuracy and stability. The results reveal that lock-in phenomena occur within specific UR ranges for each KC value, with resonance peaks identified at  = 5 for KC = 5,  = 10 for KC = 10,  = 15 for KC = 15, and  = 20 for KC = 20. Increasing KC values amplify the interaction between flow and structural responses, producing multi-mode vibrations and nonlinear coupling between inline and transverse motions. Furthermore, galloping phenomena were detected at higher UR, indicating a transition from vortex-induced vibration to hydrodynamic instability. These findings contribute to a deeper understanding of FIV dynamics in oscillatory environments, offering insights for optimizing offshore structure design and wave energy harvesting devices.
SIFAT MEKANIK DAN FISIK 3D-PRINTED DENTAL PHOTOPOLYMER RESINS DALAM KONDISI PEMROSESAN YANG BERBEDA Ahmad Mamba'udin; Muhammad Akhsin Muflikhun; Adam Zuyyinal Adib; Dianisa Khoirum Sandi; Elfrida Rizky Riadini; Yuris Bahadur Wirawan
Scientific Journal of Mechanical Engineering Kinematika Vol 10 No 2 (2025): SJME Kinematika Desember 2025
Publisher : Mechanical Engineering Department, Faculty of Engineering, Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/sjmekinematika.v10i2.796

Abstract

Photopolymer resins have widely applied in dentistry to fabricate temporary restorations. This work gives a complete characterization of a dental non-castable photopolymer resin prepared via Digital Light Processing (DLP) 3D printing. Specimens were printed at layer thicknesses of 0.05, 0.075, and 0.1 mm, followed by post-cured treatments under UV light for 10, 20, and 30 minutes. A series of material characterization tests were performed, including assessments of hardness, moisture absorption behavior, and density measurements. The results indicate that hardness and moisture content are significantly impacted by post-curing time, while extended curing times resulted in greater specimen’s hardness and decreased moisture content. An increase in layer thickness led to a gradual reduction in hardness. A maximum hardness value of 57.7 Shore D was observed in the 3D-printed specimen, along with a highest moisture content of 1.05% MC. As expected, the specimens exhibited consistent density (1.19 ± 0.02 g/cm³) throughout all layer thickness and curing time variations. This study highlights the critical need to understand how process parameters affect dental non-castable photopolymer resin properties prior to clinical implementation.
Pengenalan Sistem Mesin Pesawat Bagi Siswa SMK Nasional Berbah Ahmad Mamba’udin; Elfrida Rizky Riadini; Arif Pambekti
AMMA : Jurnal Pengabdian Masyarakat Vol. 3 No. 12 : Januari (2025): AMMA : Jurnal Pengabdian Masyarakat
Publisher : CV. Multi Kreasi Media

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

This activity aims to provide students of SMK Nasional Berbah with basic insights and understanding of aircraft engines. The limited access to practical knowledge of aviation technology serves as the main rationale for implementing this program. Through this activity, students receive materials covering fundamental theories of aircraft engines, types of engines, the working principles of turbine and piston engines, as well as visual and interactive demonstration sessions. The methods used include interactive lectures, group discussions, and component introductions through video-based media. The results indicate an improvement in students' understanding of basic aircraft engine concepts and a growing interest in the field of aviation. This activity aims to spark vocational school students’ interest in aviation science.
Model Regresi Kuadratik pada Pengepresan Biji Kemiri Dita Anies Munawwaroh; Abdul Syukur Alfauzi; Adhy Purnomo Purnomo; Ali Sai’in Sai’in; Elfrida Rizky Riadini
Journal of Mechanical Engineering and Applied Technology Vol. 4 No. 2 (2026): VOLUME 4 ISSUE 2 YEAR 2026 (JULY 2026)
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jmeat.v4i2.7642

Abstract

Vegetable oil (seeds oil) is produced from seeds. To obtain vegetable oil, a seed extraction machine is required. Seed pressing machines have specifications based on their extraction method. In this study, candlenut seed oil was produced using an extraction machine using the extrusion method. This process uses a combination of heating, friction, and high pressure. A quadratic regression model was used to predict the effect of temperature on the volume of oil produced. The results showed that the optimal temperature for producing candlenut oil is 95.96 degrees Celsius.
Beyond a Single Damping Coefficient: Experimental Mapping of Nonlinear and Stroke-Dependent Automotive Shock-Absorber Behaviour Avicenna An-Nizhami; Ignatius Gunawan Widodo; Muhammad Showi Nailul Ulum; Elfrida Rizky Riadini; Ahmad Mamba’udin; Yuris Bahadur Wirawan
Journal of Mechanical Engineering and Applied Technology Vol. 4 No. 2 (2026): VOLUME 4 ISSUE 2 YEAR 2026 (JULY 2026)
Publisher : Politeknik Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jmeat.v4i2.7842

Abstract

Shock absorbers are commonly represented by a constant viscous damping coefficient, although their actual force response may vary nonlinearly with piston velocity, stroke amplitude, and operating conditions. This study experimentally compared the damping characteristics of original and aftermarket rear shock absorbers using a laboratory test rig with variable-speed and variable-stroke operation. Both specimens were tested at strokes of 60, 90, and 120 mm and excitation frequencies of 0.5–2.0 Hz, corresponding to peak piston velocities of 0.0942–0.7539 m/s. Maximum damping forces were measured using a force gauge, and the resulting force–velocity relationships were evaluated before and after modification of the test rig. Three-term sinusoidal functions were also fitted to the measured data using the MATLAB Curve Fitting Tool. Both shock absorbers exhibited nonlinear digressive behaviour, characterised by a rapid force increase at low-to-intermediate velocities followed by a stroke-dependent high-speed plateau. Matched-velocity comparisons showed that damping force varied with stroke even at approximately equal peak velocities, demonstrating that the response was not governed by piston velocity alone. Using the post-modification data, the aftermarket shock absorber generated an average damping force 15.8% higher than the original unit over the complete test matrix. Its peak force exceeded that of the original shock absorber by 29.4%, 9.8%, and 12.6% at strokes of 60, 90, and 120 mm, respectively. The corresponding apparent damping coefficients were also consistently higher for the aftermarket unit. These findings demonstrate that shock-absorber performance should be evaluated using experimentally determined force–velocity operating maps across multiple strokes and velocities rather than a single nominal damping coefficient.
Co-Authors Abdul Syukur Alfauzi Adam Zuyyinal Adib Adhy Purnomo Purnomo Ahmad Mamba'udin Ahmad Mamba’udin Ali Sai’in Sai’in Amran Yobioktabera An Nizhami, Avicenna Antoro, Daffa Yudha Akbar Putra Apriandi, Nanang Apriandi Arif Pambekti Bambang Sumiyarso Dianisa Khoirum Sandi Dita Anies Munawwaroh Ghozali, Hanif Faizal Huda, Muhamad Nurul Ignatius Gunawan Widodo Janitra, Atikah Ayu Lathief, Muttabik Fathul Marliyati Marliyati, Marliyati Muhammad Akhsin Muflikhun Muhammad Showi Nailul Ulum Nanang Apriandi Nanang Budi Sriyanto Padang Yanuar Setiawan, Trio Setyawan, Martando Robby Timotius Anggit Kristiawan Ulum, Showi Nailul Widodo, Ignatius Gunawan Yuris Bahadur Wirawan Yusuf Dewantoro Herlambang