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Assessing the Structural Performance of Bolted Rail Joints Employing Various Fishplate Models via Finite Element Analysis
(2026-01-01)
Le, Sai Kham
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Wongsa-Ngam, Jittraporn
In railway tracks, fishplates are attached to each side of two rail ends and secured with four bolts, providing what is known as a bolted rail joint (BRJ). This rail joint is involved in complex interactions between multiple components under wheel loads, leading to stress and deformation of each component, potentially resulting in failures of the railway track. In this study, the different roles of selected fishplate models in the structural performance of a BRJ under static load are investigated using finite element analysis with ABAQUS CAE. Three fishplate models are examined: a thin cross-section, a thick cross-section, and a modified design. The first two models are currently used in rail transportation, while the novel modified version is designed to enhance the structural performance of BRJs. Preliminary results indicate that using the modified fishplate significantly reduces stress on the upper rail fillet and fishplate. Additionally, vertical displacement in both the rail and fishplate is diminished. These improvements are expected to increase the service life and reliability of BRJs, thereby contributing to safer and more cost-effective railway operations.
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Sustainable Reinforcement Methods for Brick Masonry Walls: An Experimental and Finite Element Analysis Approach
(2025-07-01)
Mehmood, Tahir
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Abid, Muhammad Amer
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Chatveera, Burachat
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Sua-Iam, Gritsada
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Saingam, Panumas
This study investigates the enhancement of axial and shear strength in brick masonry walls reinforced with steel and fiberglass meshes. The novelty of this study lies in its thorough evaluation of various reinforcement types and their influence on both axial and shear strength, offering valuable insights to enhance the performance of brick masonry structures. By using steel and fiberglass meshes for reinforcement, the study promotes the use of durable materials that can extend the lifespan of brick masonry structures, reducing the need for frequent repairs and replacements. The findings reveal that double-layer steel mesh delivers the highest strength, effectively reducing brittleness and improving deformation capacity in both single- and double-brick walls. Specifically, single-brick walls exhibited increases in compressive strength of 38.8% with single-layer steel mesh, 31.2% with fiberglass mesh, and 19.7% with plaster. In contrast, double-brick walls showed enhancements of 73.6% with double-layer steel mesh and 43.5% with fiberglass mesh. For shear strength, single-brick walls improved by 115.1% with single-layer steel mesh, 91.3% with fiberglass mesh, and 42.1% with plaster, while double-brick walls experienced increases of 162.7% with double-layer steel mesh and 132.5% with fiberglass mesh. Additionally, Abaqus modeling under axial and diagonal compression closely matched experimental results, revealing less than a 10% discrepancy across all reinforcement types.
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Multiphysics to Investigate the Thermal and Mechanical Responses in Hard Disk Drive Components Due to the Reflow Soldering Process
(2024-09-01)
Kimaporn, Napatsorn
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Samakkarn, Chawit
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Thongsri, Jatuporn
In hard disk drive (HDD) manufacturing, a reflow soldering process (RSP) implements heat generated by the welding tip to melt a solder ball for bonding the following essential HDD components: a flexible printed circuit (FPC) and a printed circuit cable (PCC). Since the mentioned components are tiny and comprise many thin material layers, an experiment to study thermal and mechanical responses is complex and not worth it. Therefore, a static state multiphysics consisting of thermal analysis (TA) and structural analysis (SA) was employed to investigate both responses. First, the experiment was established to mimic the RSP, measuring the temperature generated by the actual welding tip. Then, the measured temperature was defined as the boundary conditions with the pressing force (F) for the TA and SA based on the actual operating conditions. As expected, the TA results revealed the temperature distribution in the HDD components, which was consistent with the theory and results from previous work and confirmed this work’s credibility. Significantly, the SA reported severe total deformation (δ) in FPC’s top and bottom ends. The maximum δ was 0.72–0.88 mm for the F of 0–1 N. The stronger the F, the greater the δ. This research highlights that multiphysics can investigate both responses in HDD components as slight as 0.1–100 microns thick, which can be used to develop a high-efficacy RSP.
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The Development of a High-Efficiency Small Induction Furnace for a Glass Souvenir Production Process Using Multiphysics
(2024-09-01)
Thongsri, Jatuporn
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Poopanya, Piyawong
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Sriphalang, Sanguansak
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Pattanapichai, Sorathorn
A small induction furnace (SIF), which has the important components of copper coils, a ceramic jig, and a graphite crucible, employed for a glass souvenir production process, has been developed as a form of clean technology for multiphysics, consisting of electromagnetics analysis (EA) and thermal analysis (TA). First, two experiments were established to measure parameters for multiphysics results validation and boundary condition settings. Then, the parameters were applied to multiphysics, in which the EA revealed magnetic flux density (B) and ohmic losses, and the TA reported a temperature consistent with the experimental results, confirming the multiphysics credibility. Next, a ferrite flux concentrator was added to the SIF during development. Multiphysics revealed that PC40 ferrite, as a flux concentrator with a suitable design, could increase B by about 159% compared to the conventional SIF at the power of 1000 W. As expected, the B increases alongside the increase in power applied to the coils, and is more densely concentrated in the flux concentrator than in other regions, enhancing the production process efficacy. Lastly, the developed SIF was employed in the actual process and received good feedback from users. The novel research findings are the developed SIF and methodology, exclusively designed for this research and practically employed for a glass souvenir production process.
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The Benefits of Using Rubber Material in Two Variances: The Rubberized Concrete and the Natural Rubber Sheet, to Strengthen Concrete Barriers for Crash Energy Absorption
(2024-08-01)
Aung, Lwin Lwin
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Jarasjarungkiat, Amphon
Given the frequency of road accidents, a critical evaluation of the strength of road safety devices has become imperative. This research explores reinforced concrete barriers protected with rubber materials, incorporating different ratios of rubber powder derived from waste and various thicknesses of natural rubber sheets. Two approaches were employed: the first used crumb rubber from recycled tires to prepare barrier samples with varying rubber content ratios (0%, 15%, and 30% by volume); the second involved attaching concrete barriers with natural rubber sheets of different thicknesses (30 to 70mm). These barriers were subjected to frontal impact loads generated by vehicles traveling at 35mph. A crash dynamic was conducted using nonlinear explicit analysis in numerical modeling within a finite element simulation framework. The primary objectives were to monitor the crash energy absorbed by the rubber material, scrutinize deflection patterns, and assess overall energy absorption capabilities. The results indicated that natural rubber sheets absorbed approximately 20% to 47% of the maximum internal energy, reducing the impact on the concrete barrier. The 30% crumb rubber content of barriers also exhibited significantly higher energy dissipation than standard concrete barriers. This improvement in energy absorption and deflection properties carries significant implications, including reduced maintenance costs, decreased accident-related injuries, and minimized vehicle damage. These findings underscore the importance of developing and implementing rubber materials in two methods to enhance impact resistance and energy absorption in road safety infrastructure.
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Development of a Small Ultrasonic Cleaning Bath based on Harmonic Response Analysis
(2024-01-01)
Worradechaudom, Warakorn
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Chaiaiad, Chatchapat
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Thongsri, Jatuporn
This article reports the development of a 0.27 L small ultrasonic cleaning bath (SUCB) with a 45 kHz single transducer to enhance cleaning efficacy based on harmonic response analysis (HRA). First, the HRA results revealed the uneven acoustic pressure inside the SUCB emerged from the transducer, depending on the applied voltage. As expected, the higher the applied voltage, the greater the acoustic pressure, and away from the transducer, the acoustic pressure decreased, consistent with the foil corrosion test, confirming the research methodology's credibility. Then, the transducer has been redesigned to develop the SUCB. Last, using the HRA, the simulation results indicated that the redesigned transduce, adding front and back masses like a horn shape, enhanced the acoustic pressure and helped to increase cleaning efficacy compared to the conventional SUCB. The findings were applied to develop a new generation of the SUCB. This article presents a step-by-step HRA technique that can be practically used in manufacturing design.
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Transient Thermal-Electric Analysis of Peltier Cooling Plate for Developing a Mini Refrigerator
(2024-01-01)
Chaiaiad, Chatchapat
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Thongsri, Jatuporn
This article reports a transient thermal-electric analysis (TEA), a simulation of a Peltier cooling plate (PCP) aimed to develop into a mini refrigerator soon. This conventional PCP includes 110 Peltier cells, which are a series of connecting cells, and two sandwiched ceramic plates. First, the experiment measured the PCP's applied current (I) and temperature (T) under the desired conditions. Then, the TEA was employed to determine the I and T of the PCP, which were compared with the experimental results. As expected, the comparison shows the consistency between the simulation and experimental results, validating the credibility of the methodology and simulation results. The simulation results revealed that the temperature difference (Δ T) between the two sandwiched ceramic plates increased with the increase of I and the number of cells, as expected. Last, the proposed model of PCP, I of 500 mA, 126 Peltier cells, and reducing the gap between cells, could generate T of -2.3761C on the cool ceramic plate lower than the conventional model of -1.6495 C, about 44% reduction at the same I, suitable for developing the mini refrigerator. The novel of this article is the practical methodology of using transient TEA to help design the PCP for specific purposes.
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A Development of Welding Tips for the Reflow Soldering Process Based on Multiphysics
(2022-11-01)
Thongsri, Jatuporn
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Jansaengsuk, Thodsaphon
A reflow soldering process (RSP) is generally implemented in advanced manufacturing factories for welding small electronic components together to create a product using heat generated at the welding tip (WT). Improper WT design and operating conditions may lead to defects in some products; therefore, optimizing both is immensely significant in developing the RSP. Accordingly, this article proposes a successful RSP development based on multiphysics in a hard disk drive factory consisting of transient thermal-electric and structural simulations. First, a new shape series WT was designed, and a conventional shape, parallel WT, was considered as a case study. Then, they were assembled and experimented with the RSP actual operating conditions to collect essential data. Next, the heat transfer was determined using a transient thermal-electric simulation (TES). The simulation results showed uneven WT temperatures depending on applied voltages, time, and shapes, which were consistent with the experimental results. The higher the applied voltage, the greater the temperature generated at the WT. Finally, after using TES results as loads, the structural simulation showed WT total deformations, which could be consistent with actually occurring defects. The findings from this research are a new design of series WT and proper multiphysics methodology for developing the RSP.
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Gas Flow and Ablation of 122 mm Supersonic Rocket Nozzle Investigated by Conjugate Heat Transfer Analysis
(2022-09-01)
Thongsri, Jatuporn
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Srathonghuam, Kamonwan
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Boonpan, Adulyasak
The propellant gas flow of a supersonic rocket in inappropriate operating conditions can cause excessive ablation inside a nozzle. In this research, conjugate heat transfer analysis (CHTA), consisting of computational fluid dynamics (CFD) and finite element analysis (FEA), was applied to investigate the gas flow and ablation of a 122 mm nozzle as a case study in the transient state, based on actual operating conditions. First, the nozzle was tested in a static experiment. Then, the experimental results were employed for CHTA settings and validation. Next, after completing the CFD calculation, the results revealed that the nozzle’s gas flow, temperature, pressure, Mach number, shock, etc. were consistent with theoretical results. Finally, using the CFD results as loads, the FEA results showed the equivalent von Mises stress (σ<inf>v</inf>), which was consistent with the ablation results from the experiment, as expected. The more the σ<inf>v</inf>, the greater the ablation. Both σ<inf>v</inf> and ablation were high near the throat and decreased further away. In addition, increasing the insulators’ thickness reduced σ<inf>v</inf>, leading to ablation reduction. The research findings contribute to an understanding of ablation and the methodology of employing CHTA to improve the design of 122 mm and other nozzles with reduced ablation for higher efficacy.
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Optimization of a heavy-duty elevated thin shell structure
(2022-08-01)
Nassir, Azizah Abdul
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Min, Yee Hooi
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Petchsasithon, Arthit
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Senin, Syahrul Fithry
Optimization means the mathematical determination of the optimal decisions out of diverse alternatives. Based on the preceding Finite Element Analysis (FEA), a proposed shell produced a maximum stress that exceeded the design value. To make the design feasible, an optimization was done to minimize the maximum stress by using the gradient method. The performance of the structure can be optimized to fulfil the design requirements with the optimum value of displacement to achieve the objective function. The results show that the optimum displacement is 8.8mm, which reduced the maximum stress by 99.94% from the initial level. Thus, optimization methods are important for new applications of shell structures to find their best parameters in the design stage.

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