Suranaree Journal of Science and Technology

COMPARATIVE ASSESSMENT OF ADVANCED STRUCTURAL OPTIMIZATION PARADIGMS FOR AEROSPACE LOAD-BEARING COMPONENTS

Shiney Herald Gompana — 2026-08-06

This study presents a systematic comparative evaluation of four structural optimization methods - Solid Isotropic Material with Penalization (SIMP), Level Set, Mixable Density, and Shape optimization applied to aerospace components under standardized conditions. A helicopter pitch arm subjected to 1077 N loading derived from rigid body dynamics analysis served as the benchmark case. The investigation encompassed 36 optimization scenarios with weight reduction targets of 30-50%, stress constraints of 150-200 MPa, and a 3 mm minimum feature size for additive manufacturing. Level Set methods achieved 388.5 N·mm compliance compared to 412.7 N·mm for SIMP at 40% weight reduction, representing 6% superior stiffness at 3.75× computational cost. SIMP generated 8-12% intermediate densities requiring post-processing, while Level Set produced binary material distributions suitable for direct manufacturing. Stress constraints below 175 MPa activated in >25% of the design domain, forcing material redistribution that increased compliance by 18-25%. Manufacturing constraints significantly influenced performance: 3 mm features incurred 12% compliance penalty while 5 mm conventional machining constraints resulted in 38% penalty. The results establish that 35-45% weight reduction with 175-200 MPa stress limits represents the optimal parameter range for aerospace applications, providing quantitative guidance for method selection based on specific performance-cost requirements.

INFRARED AND HOT-AIR DRYING OF STR20 RUBBER: ENHANCED EFFICIENCY AND QUALITY THROUGH ADVANCED MODELING

Saysunee Jumrat — 2026-08-06

This study investigates the drying kinetics and quality characteristics of Standard Thai Rubber (STR20) using a novel infrared-hot-air drying system. The system was designed to automate temperature and moisture control for three grades of STR20, representing alternative ratios of natural cup lump rubber to smoked natural rubber sheet. Seven mathematical models were evaluated for best fit to the drying data, with the Logarithmic and Approximate Diffusion models showing the highest accuracy. Results demonstrated that infrared-hot-air drying achieved efficient energy consumption (average SEC of 25.82 MJ/kg), while preserving desirable rubber properties such as initial plasticity, plasticity retention index, viscosity, and volatile matter content within industry standards. These findings suggest that infrared-assisted drying can improve drying efficiency and product quality, offering an effective alternative for the rubber industry.

AN APPROACH TO PRODUCTION SCHEDULING FOR REDUCING CARBON FOOTPRINT IN AN AGRICULTURAL TRANSPORT VEHICLE MANUFACTURING COMPANY: A CASE STUDY IN UTTARADIT PROVINCE

Chatchaphon Ketviriyakit — 2026-08-06

This study investigates a production scheduling problem for an agricultural vehicle manufacturer in Uttaradit Province. The primary goal is to generate an improved production schedule using a mathematical model. The model is designed to minimize the total time taken to produce an entire product known as make span, while also tracking the environmental impact, or product carbon footprint (CFP), during the production of each part. A computer program was created and a local search heuristic was used to find the optimal schedule. The data was obtained from customer orders and the company's production and maintenance teams. It included information such as the number of machines they had, how long each machine needed to set up, how long each product needed to produce, how much electricity they used, how much waste they generated, and the rules and constraints they imposed on production. The production scheduling problem was divided into three levels: small, medium, and large, allowing for the determination of the optimal schedule for each scenario. The results show that the mathematical model performs well on all problem sizes. For example, in the small-scale case with six jobs and seven machines, the model took 6,961.23 minutes to compute, which took only 0.214 seconds for all machines to be fully utilized, and the CFP was 91.791 kg of CO₂ equivalent. In contrast, the company's original large-scale schedule took 38,561.12 minutes, or approximately 81 working days, at an 8-hour workday. However, with the revised schedule, the time was reduced to 26,365.22 minutes, or approximately 57 working days, a saving of 24 days. Using this mathematical model, the total production time was reduced by 11,139.94 minutes, efficiency was improved by 28.89%, and CFP was reduced by 497.759 kilograms of carbon dioxide equivalent, successfully achieving the main goal of the research.

PROCESS CAPABILITY ANALYSIS OF WORK PROCEDURES TO REDUCE WASTE : A CASE STUDY OF AN AUTOMOTIVE PARTS MANUFACTURING PLANT.

Phongsak Runkratok — 2026-08-06

This study focuses on analyzing and improving the process capability for waste reduction in an automotive parts manufacturing plant. A cause-and-effects diagram was employed to investigate and identify the root causes of defects. Process capability analysis was then applied to evaluate the effectiveness of improvements of the Work Procedures. The initial defect rate was 2.9 percent, consisting mainly of surface scratches, dents, discontinuous surfaces, and poor surface finishes. The primary causes were inappropriate insert selection and cutting direction, leading to inadequate tool strength and premature wear. Prior to the improvement, the process capability index (Ppk) was 0.67. After implementing the proposed improvements, the three-step modification process includes altering the cutting tool path direction, adjusting the feed rate, and changing the cutting insert. The defects were completely eliminated, tool life was significantly extended, the process capability index increased to 1.39, and production costs were reduced by 5.10 percent

ATTENTION-ASTFF-NET: A CHANNEL-AWARE ADAPTIVE SPATIOTEMPORAL FUSION NETWORK FOR VEHICLE RECOGNITION

Praetawan Jarutan — 2026-08-06

Vehicle recognition systems face challenges in simultaneously capturing spatial appearance characteristics and temporal structural patterns. This study proposes Attention-ASTFF-Net, a channel-aware adaptive spatiotemporal fusion network that enhances vehicle type and vehicle make recognition. The proposed framework extracts spatial features with a convolutional backbone and temporal representations with a convolutional 1D-based module. An adaptive fusion mechanism then combines these features to obtain a comprehensive spatiotemporal representation. Channel-wise attention mechanisms, including Efficient Channel Attention (ECA-Net), Gated Channel Transformation (GCT), Squeeze-and-Excitation (SE) Networks, and Selective Kernel Networks (SKNet), are integrated to emphasize important feature channels and improve discriminative capability. Experimental results on the Vehicle Type Image Dataset Version 2 (VTID2) and the Vehicle Make Image Dataset (VMID) show that the proposed network consistently outperforms the baseline ASTFF-Net and other convolutional neural network architectures. Channel-wise attention integration improves localization, feature selectivity, and prediction stability. The proposed network achieves over 99% accuracy on VTID2 compared with approximately 96% achieved by previous methods, and over 97% on VMID compared with 93.11% achieved by existing approaches. Furthermore, Attention-ASTFF-Net with the SE module demonstrates strong computational efficiency at 5.113 giga floating point operations.

STRUCTURAL HEALTH ASSESSMENT OF RCC MEMBERS USING NON-DESTRUCTIVE AND PARTIAL DESTRUCTIVE TECHNIQUES AT ELEVATED FLOOR LEVEL OF A SPORTS STADIUM

Vimal Kumar Gupta — 2026-08-06

This study presents a comprehensive evaluation of reinforced cement concrete (RCC) members situated at the +10.80 m level of an international cricket stadium in Gwalior, Madhya Pradesh, utilizing a series of nondestructive Tests (NDT) and Partial Destructive Tests (PDT). The investigation was undertaken to assess the in-situ material quality and structural integrity of slabs and beams using Ultrasonic Pulse Velocity (UPV), Rebound Hammer, and Core Compression and Chemical Analysis. The UPV results indicated a significant portion of the slab concrete quality falls within the "doubtful" category, while beams ranged from "medium" to "good" quality. Rebound hammer readings generally revealed surface hardness, which is indicative of a lower compressive strength than the design grade (M30). Core compression tests showed variable strength values, with most cores confirming design-grade strength, although the chloride content in several samples exceeded permissible limits, indicating a potential risk of corrosion-induced deterioration. No carbonation effects were observed, and the sulfate content was within the acceptable bounds. This integrated approach highlights the need for localized rehabilitation and continuous monitoring to maintain structural reliability in large public infrastructure.

VALUE ENGINEERING FOR STRUCTURAL COST OPTIMIZATION IN HIGH-RISE RESIDENTIAL BUILDING PROJECTS

Sunitat Kanphuck — 2026-08-06

This study applied the concept of value engineering (VE) to the structural design of a 25-story reinforced concrete residential building in Bangkok, Thailand. The primary objective was to reduce construction costs while maintaining structural safety, serviceability, and overall performance. The VE process focused on major structural components. This review was supported by an updated soil investigation and refined structural modeling, with the results verified against applicable ACI, AISC, ASCE, and local Bangkok regulations. Structural analysis was performed using ETABS for the superstructure, with PLAXIS used to evaluate foundation behavior and soil–structure interaction. The VE study compared the original bidding with the revised design. Several modifications were introduced, including reorganization of the pile groups, revisions to pile cap geometry, foundation level adjustments, standardized column dimensions, and the removal of unnecessary link bars in the shear walls. These changes resulted in measurable cost reductions across multiple elements: columns (23.25%, THB 11,816,969), foundations (29.57%, THB 5,806,858), core walls (13.36%, THB 5,242,750), and piles (10.86%, THB 4,249,119). Subsequent performance checks confirmed that the revised structure satisfied displacement, deflection, and acceleration limits, ensuring acceptable occupant comfort and structural stability. The VE implementation achieved total savings of THB 27.11 million, an 18.14% reduction from the original cost. The final savings were below the initial VE target with additional reductions identified through material reuse and improvements in construction methods. The findings demonstrated that VE is an effective and practical approach for cost optimization in high-rise residential projects without compromising safety or design intent.

INVESTIGATION OF HOLMIUM-DOPED PHOSPHO-TELLURITE GLASS SYSTEMS FOR LASERS

Wiraphat Thanyaphirak — 2026-08-06

This study explores the properties of Holmium-doped phospho-tellurite glass, with varying concentrations of Ho₂O₃, measuring the physical, structural, optical, and luminescence characteristics of the glass. Physical properties including density, molar volume, and refractive index are measured and analyzed. XRD is used to confirm the amorphous nature of the glass for structural properties, while FTIR is used to confirm bonding in the glass system. Absorption and luminescence are measured within the wavelength range of 200 - 2000 nm and 400 - 750 nm, respectively. The obtained spectra were analyzed using the Judd-Ofelt theory, which provides insights into the energy levels of Ho³⁺ ion doped in the phospho-tellurite glass matrix. Notably, our analysis of the spectral line corresponding to the ⁵F₄ → ⁵I₈ transition (~ 529.0 nm), showcases a highly stimulated emission cross-section. The calculated oscillator strength, Judd-Ofelt intensity parameters, branching ratio, and other parameters further elucidate the potential of Ho³⁺ ion doped phospho-tellurite glass for efficient laser emission in this glass system.