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Teknomekanik
Published by Universitas Negeri Padang
ISSN : 26219980     EISSN : 26218720     DOI : 10.24036/tm.
Core Subject : Engineering,
Mechanical Engineering
Teknomekanik is an international journal that publishes peer-reviewed research in engineering fields (miscellaneous) to the world community. Paper written collaboratively by researchers from various countries is encouraged. It aims to promote academic exchange and increase collaboration among scientists, engineers and researchers to support sustainable development goals.
Arjuna Subject : Teknik (semua kategori) - Teknik Mesin
Articles 8 Documents
 1 
Search results for , issue "Vol. 9 No. 1 (2026): Regular Issue" : 8 Documents clear
Multiclass gas pipeline leak detection using multi-domain signals and genetic algorithm-optimized classification models Suprihatiningsih, Wiwit; Romahadi, Dedik; Pranoto, Hadi; Youlia, Rikko Putra; Anggara, Fajar; Rahmatullah, Rizky
Teknomekanik Vol. 9 No. 1 (2026): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v9i1.38372

Abstract

Pipeline networks are critical infrastructure for oil and gas transport because the occurrence of leaks can rapidly escalate into safety, economic, and environmental crises. Operators are practically required to identify the presence and type of leaks; however, applying multiclass recognition is challenging when labeled data and computing power are limited. Therefore, this study proposes a three-stage pipeline which consists of: (1) adopting the GPLA-12 dataset of acoustic or vibration signals spanning 12 leak types; (2) extracting multi-domain features by combining time-domain descriptors with Power Spectral Density (PSD)-based spectral features; and (3) applying a genetic algorithm (GA) as a wrapper for feature selection to enhance discriminability and reduce dimensionality, which was followed by benchmarking seven conventional classifiers and GA-based refinement of the top model with a focus on the feature subset and hyperparameters. A maximum accuracy of 96.35% was achieved on the GPLA-12 dataset with low computation time and a simple model architecture. The proposed pipeline also attained similar or better accuracy at substantially lower complexity and data requirements compared with prior deep CNN approaches. These results support timely multiclass decision-making in resource-constrained industrial settings. A key observation was that the focus was on supervised leak-type classification from acoustic or vibration signals, while localization, severity estimation, and multi-sensor fusion were beyond the scope of this study.
Comparative analysis of bio-inspired and topology-optimized lattices under compressive loading Arifin, Ahmad Anas; Batan, I Made Londen; Bici, Michele; Wahjudi, Arif; Pramono, Agus Sigit
Teknomekanik Vol. 9 No. 1 (2026): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v9i1.45472

Abstract

Lattice structure design is still dominated by strut-based forms and surface-based shapes, such as triply periodic minimal surfaces (TPMS), which both exhibit overlapping limitations. Strut lattices often show strong anisotropy because their response depends heavily on cell orientation, while TPMS lattices are difficult to adjust when bounded by geometric constraints. These conditions eventually led to stagnation in the development of lattice morphology. Hybrid and topology-optimization methods have appeared as possible alternatives, but many of them still produce modified versions of classical patterns. This study examined two lattice geometries: the Pyramorph, inspired by the shape of a pyramid, and the Topomorph, generated through a topology optimization framework. Both structures were designed using a CAD unit cell patterning technique and manufactured using the FDM method, with relative densities ranging from 0.40 to 0.44. Their mechanical behaviour was examined through FEA simulation and uniaxial compression testing. The parameter variations included cell orientations of 0°, 15°, 30°, and 45°, and cell sizes of 8 mm and 12 mm within a 24 mm specimen. The Topomorph showed superior strength, reaching 15–20 MPa, while the Pyramorph reached only 7–8 MPa. The highest value, about 20.5 MPa, was obtained from the Topomorph at 0° and with an 8 mm cell size. Failure modes indicated buckling and delamination in the Pyramorph, while the Topomorph tended to collapse progressively. These findings indicate that topology optimization combined with CAD-based patterning could significantly improve lattice performance.
Grid convergence analysis of an H-Darrieus wind turbine for multiple blade configurations Nasution, Sanjaya Baroar Sakti; Nasution, Dian Morfi; Wijaya, Elang Pramudya; Ompusunggu, Oki Suprada
Teknomekanik Vol. 9 No. 1 (2026): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v9i1.45272

Abstract

Mesh size and number significantly affected the accuracy of CFD simulations in wind turbine analysis. However, most studies focused solely on turbine performance, such as the blade torque or power coefficients. Therefore, this study adopted a broader perspective by analyzing the influence of mesh resolution on both aerodynamic performance and key fluid-dynamic parameters, including vorticity and pressure coefficients, for an H-type Darrieus vertical-axis wind turbine. Two-dimensional CFD simulations were performed using ANSYS Fluent with the k–ω SST turbulence model. Five mesh levels were evaluated across different blade configurations, and the Grid Convergence Index (GCI) was used to quantify discretization errors. The results indicate that increasing mesh resolution yields more stable torque predictions and improved resolution of near-wall flow features, with consistent grid-convergence behaviour observed across all blade configurations. GCI analysis shows that discretization errors consistently decrease as the mesh becomes finer. It also shows that a grid size of about 1.6 x 105 cells is sufficient to keep errors below 5%. These findings show that including flow-field details in mesh sensitivity analysis gives a better way to check the accuracy of CFD simulations for Darrieus wind turbines.
Uniaxial and biaxial hot pressing of PVDF films: A pathway toward high-performance piezoelectric sensors and energy harvesters Suprapto, Suprapto; jubaidah, Jubaidah; Triono, Selamat; Gunawan, Harianto; Lisyanto, Lisyanto; Nugraha, Aditya Sukma; Aldori, Yopan rahmad
Teknomekanik Vol. 9 No. 1 (2026): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v9i1.44972

Abstract

The piezoelectric efficiency of Poly (vinylidene fluoride) (PVDF) membranes becomes restricted by the challenge of generating and stabilizing electroactive β-phase during processing. Stretching requires control of deformation parameter, while solvent-based methods bring environmental and occupational health risks. This research suggests hot-pressing as an alternative method for enhancing β-phase fraction, utilizing multidirectional stress without solvent or chemical exposure. This study systematically compares uniaxial hot-pressing (Uniaxial HP) and biaxial hot-pressing (Biaxial HP) setups to determine which stress distribution is more effective at promoting changes and improving piezoelectric properties in PVDF membranes. The main objective of this research is to systematically evaluate and compare the impacts of uniaxial and biaxial hot-pressing on the crystalline phase transformation and electromechanical performance, including the piezoelectric coefficient (d33) and output voltage response of PVDF membranes. PVDF pellets were hot-pressed at 220o C under a pressure of 60 MPa for 15 minutes followed by rapid quenching in ice water. X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed phase composition, correlated with performance via the piezoelectric coefficient (d33), and assessed piezoelectric activity. Experimental results show that biaxial loading provides a higher b-phase fraction (50.47%) compared to untreated membranes (47.80%) and UHP samples (49.30%). The crystallinity and the piezoelectric coefficient also increased to 49% and 18.8 pC/N, respectively. Biaxial stress pattern during hot-pressing induces favourable thermodynamic and kinetic conditions for b-phase expansion. Beyond phase-related results, the approach delivers competitive piezoelectric effectiveness while maintaining simplicity and reducing solvent-dependent processing steps.
Effects of process parameters on the evaporative pattern casting of scrap aluminum–RHA composites Siswanto, Rudi; Ghofur, Abdul; Subagyo, Rachmat; Tamjidillah, Mastiadi; Mahmud, Mahmud; Ma’ruf, Ma’ruf; Nordiman, Adi
Teknomekanik Vol. 9 No. 1 (2026): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v9i1.46072

Abstract

This study investigates the fabrication and characterization of aluminium matrix composites reinforced with rice husk ash (RHA), using scrap aluminium as the base material and evaporative pattern casting as the manufacturing method. The work evaluates the effects of three key independent variables: pouring temperature, aluminium (Al)-RHA composition ratios, and styrofoam pattern thickness on the resulting composite properties. The dependent variables examined include surface roughness, Brinell hardness, and dimensional shrinkage-expansion. Experimental results show that increasing the pouring temperature and adjusting the composition ratio significantly influence the mechanical and physical properties of the composites. The highest hardness (45.6 HB) and fluidity (252.65 mm) were achieved at a 60:40 composition ratio and a pouring temperature of 750 °C, albeit at the cost of increased porosity. Additionally, the styrofoam pattern thickness was found to affect the dimensional stability and surface roughness of the composites, with thicker patterns resulting in higher surface roughness. This study highlights the potential of utilizing rice husk ash as a reinforcing material in aluminium matrix composites, offering a sustainable approach to improving material properties. The findings suggest that an optimal balance of composition ratio, pouring temperature, and pattern thickness is crucial to achieving desirable mechanical and physical characteristics, with implications for advanced manufacturing processes in the materials industry.
Optimization of bio-based cellulose-phosphate hydrogel production from rice husk waste using the Taguchi method Aprilyanti, Selvia; Pratiwi, Irnanda; Andalia, Winny; Aprianti, Tine; Faritzie, Hariman Al
Teknomekanik Vol. 9 No. 1 (2026): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v9i1.47172

Abstract

This work reports the development and statistical optimization of a fully Bio-based absorbent hydrogel synthesized from rice husk–derived cellulose via phosphoric acid crosslinking. Cellulose was extracted through sequential chemical treatments and subsequently converted into a phosphate-crosslinked hydrogel using a controlled synthesis process. A Taguchi L16 (4⁵) orthogonal array was employed to optimize four key synthesis parameters: cellulose content, reaction time, heating temperature, and phosphoric acid volume. Hydrogel structure and morphology were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). FTIR results confirmed the formation of phosphate ester linkages, indicating successful crosslinking, while SEM observations revealed a porous and interconnected network structure favorable for water absorption. The optimized hydrogel formulation achieved a maximum swelling ratio of 91.25 g/g, demonstrating effective absorbent performance despite the absence of synthetic monomers or grafting agents. These findings indicate that rice husk waste can be efficiently valorized into an environmentally benign absorbent material through a simple and statistically guided synthesis route, supporting sustainable hydrogel development and agricultural waste utilization.
Spatial modelling of shallow groundwater quality in coastal areas with Kriging interpolation Arbi, Yaumal; Syah, Nurhasan; Umar, Iswandi; Dewata, Indang; Gusman, Mulya; Sandra, Nevy
Teknomekanik Vol. 9 No. 1 (2026): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v9i1.47272

Abstract

This study maps shallow coastal groundwater quality in Padang, Indonesia, using four operational parameters: potential of hydrogen (pH), electrical conductivity (EC), total dissolved solids (TDS), and salinity. We characterize spatial dependence using empirical variograms, evaluate directional anisotropy, and generate prediction surfaces with Ordinary Kriging. The variogram analysis indicates stronger spatial continuity along the coastline for EC and TDS, while salinity shows shorter continuity with a distinct directional structure, reflecting localized freshwater-seawater mixing processes. Groundwater pH remains neutral to slightly alkaline and exhibits lower spatial variability than EC, TDS, and salinity. Leave-one-out cross-validation supports the reliability of the kriging estimates at the study scale, indicating low prediction error and strong agreement between observed and predicted values. The resulting thematic maps enable a three-level quality zoning that differentiates a lower-risk northern segment, a transitional central belt, and a higher-risk southern segment consistent with seawater intrusion influence. These outputs provide a practical basis for prioritizing monitoring locations, protecting vulnerable wells, and strengthening evidence-based coastal groundwater management aligned with SDG 6 Clean Water and Sanitation and SDG 11 Sustainable Cities and Communities.
Hydrodynamic optimization of a Sweptback Stern Foil for resistance reduction in flat-hull ships: A CFD-based extension of the Hull Vane concept Nabawi, Rahmat Azis; Syahri, Budi; Alfana, Yogi Dian; Fernandez, Donny
Teknomekanik Vol. 9 No. 1 (2026): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/teknomekanik.v9i1.54872

Abstract

Flat-hull ships are known to have higher resistance than streamlined hulls. Although the Hull Vane® concept has been proven effective as a stern-mounted energy-saving device through pressure-field modification and stern-wave interaction, most previous studies have focused on straight-foil configurations (straight planform). The effect of planform shape optimization, particularly the sweptback configuration, on the hydrodynamic performance of flat-hull ships is limited in the literature. This study modifies the geometry of a Hull Vane® into a sweptback stern foil and evaluates its performance using Computational Fluid Dynamics simulations. The results show that a 15° sweptback angle yields the greatest reduction in total drag. Velocity contour analysis shows a narrower wake and a more uniform velocity-gradient distribution in the stern area for the 15° swept-back stern-foil configuration compared to other configurations. Meanwhile, the turbulence length distribution shows a tendency toward reduced intensity of large-scale turbulent structures behind the ship, indicating improved wake-flow characteristics. The identified drag reduction mechanism primarily stems from improved pressure recovery and modified pressure distribution in the stern area, which is consistent with the working principle of Hull Vane®. Optimizing the sweptback planform geometry yields more efficient flow interaction than the straight-foil configuration. These findings indicate that planform optimization is an important design parameter in the development of stern foils to improve the hydrodynamic efficiency of medium-to high-speed commercial vessels.

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