Science and Engineering Connect

Bending Analysis of Functionally Graded Thick Plates on Elastic Foundations by Boundary Element Method

Tinnapop Boontos — 2025-03-26

Background and Objectives:Functionally Graded Materials (FGMs) are garnering significant attention in engineering due to their versatile applications in structural components, especially in plate structures. Their properties, which vary continuously with thickness, enable the tailoring of mechanical properties and resistance to meet specific operational needs. Analyzing the bending behavior of thick FGM plates on elastic foundations is nevertheless a complicated task, requiring consideration of the interactions between the plates and the foundations as well as the implications of variation in material properties with thickness. Although Finite Element Method (FEM) and other analytical approaches have been extensively developed to analyze the bending of thick FGM plates on elastic foundations, such methods continue to encounter limitations in managing complex boundary conditions and structural shapes. Consequently, in this research, the Boundary Element Method (BEM) was developed as an alternative for analyzing thick FGM plates on elastic foundations.

Methodology: The governing equations and boundary conditions were derived using the principle of virtual work, based on the first-order shear deformation plate theory. The properties of FGMs were modeled using a power law distribution model. The presented method was developed using the concept of the Analog Equation Method, where the differential equations of the original problem were substituted with three Poisson’s equations under fictitious forces, maintaining the original boundary conditions. These fictitious forces were generated using techniques based on the Boundary Element Method and approximated using radial basis functions. The reliability of the proposed method was assessed by comparing the results of the present research with outcomes from other established approaches.

Main Results: The numerical results obtained from the proposed method are highly accurate and precise when compared to those of other relevant research, demonstrating convergence of the solution as the number of boundary elements and internal nodes increases. Furthermore, it effectively analyzed thick FGMs plates on elastic foundations under complex conditions, such as an elastic support and elastic restraint, or plates with various shapes. Such complex problem has not been investigated in previous research studies.

Conclusions: The present research developed the Boundary Element Method (BEM) in conjunction with the Principle of Analog Equation to analyze the bending of complex thick plates made from Functionally Graded Materials (FGMs) resting on elastic foundations, considering both the boundary conditions and the plate shapes. The results demonstrate the accuracy and efficiency of the proposed methods, capable of accurately simulating the interactions and effects of material properties and various parameters on the bending response of the plates.

Practical Application: This study proposes an effective method for analyzing the bending of thick plates made from Functionally Graded Materials (FGMs) on elastic foundations, capable of analyzing plates with complex shapes and boundary conditions that are common in real-world applications. This allows for the safe and efficient design of such structures.

Development of a Cashew Nut Fryer with a Suitable Agitator Design Process and Frying Color Detection System

Amnad Tongtib — 2025-03-26

Background and Objectives: Frying cashew nuts requires experienced workers to stir the nuts in hot oil to maintain the nut temperature in the frying pan and to determine when to stop the process based on the desired nut color, hence reducing the risk of poor-tasting products. The objective of this research was therefore to develop a cashew nut fryer by designing a suitable agitator arrangement and integrating a color detection system to monitor the color of the nuts.

Methodology: A model that can be used to simulate the agitator to determine the fluid distribution pattern was devised. Then, the appropriate agitator rotational speed for frying was determined by calculating the coefficient of variation. The color measurement system was developed and utilized to capture the nut color in CIE L*a*b* color space to classify the level of fried cashew nuts from the images collected during the frying process.

Main Results: Installing an additional agitator beneath the main agitator and adjusting its orientation angle relative to the main agitator axis, bringing it closer to the pan surface, could improve the fluid distribution around the center of the pan. The results from testing the prototype show that the coefficient of variation at all five agitator rotation speeds dropped below 30 percent within the first minute. The color measurement system results indicate that the a* and b* values tended to increase as frying progressed toward completion, while the L* value tended to decrease.

Conclusions: The additional agitator improved fluid distribution across the pan. The coefficient of variation from testing on the prototype was below 30 percent within the first minute at all agitator rotation speeds. The color measurement system successfully classified the fried cashew nuts into three levels: beginning, medium, and proper frying. When cashew nuts were fried with the aid of the temperature control system and color detection system, the recommended frying time was found to be 8 minutes, resulting in a suitable product color for consumption.

Practical Application: The results from this research can be applied to other fryers or stirring machines that require product classification based on color.

Flow Measurement Using Bypass Flow Meters for Smart Farming Applications

Somchai Donjadee — 2025-03-31

Background and Objectives: Accurate flow measurement is essential in order to improve water efficiency and productivity in any irrigation system. Precision irrigation is a technique that optimizes water usage by utilizing technology to deliver the right amount of water according to crop requirement. In smart farming, this approach relies on precise water monitoring and control. However, traditional flow meters often pose significant challenges due to their high installation costs, particularly for large-diameter pipes. Bypass flow meter (BPF meter) offers a cost-effective alternative resolution for flow measurement. BPF meter measures flow in large-diameter pipes by diverting a portion of the flow through a smaller bypass pipe mounted with a flow meter. Although the BPF technique has been around for some time, its application and performance in flow measurement are still underexplored. Therefore, this study sought to fill the gap by presenting the concept, performance, and practical implementation of BPF meter as a cost-effective and accessible alternative for water flow measurement in smart farming applications.

Methodology: Experiments were conducted using BPF meters with different main pipe to bypass pipe diameter ratios (D/d = 2:1, 2.5:1, 3:1, and 4:1). To ensure consistency across experimental settings, the lengths of all pipes were fixed to focus on the examination of the effect of the diameter ratio on BPF meter performance. The bypass flow rate (Q_BP) and the total flow rate (Q) were quantified under regulated experimental settings. Each pipe diameter configuration was tested at different flow rates, with each flow rate subjected to a minimum of three tests to verify dependability and to reduce experimental errors. The relationship between Q_BP and Q was then analyzed and is expressed by the equation Q=KQ_BP, where K is the loss coefficient, which is dependent on pipe configuration. Statistical parameters, including the coefficient of determination (R²), root mean square error (RMSE), and mean percentage error (MPE) were employed to evaluate the accuracy and reliability of the model for each configuration.

Main Results: The main findings reveal that the total flow rate (Q) is directly proportional to the bypass flow rate (Q_BP), and this relationship is influenced by the pipe diameter ratio (D/d). The findings indicate a robust linear relationship between Q and Q_BP (R² > 0.99), with minor errors across all configurations. Larger D/d ratios demonstrate higher K values, indicating increased sensitivity to bypass flow measurement. The consistency of the K values across pipe configurations supports the robustness of the proposed calibrated model and illustrates the adaptability of the BPF meter for varying pipe diameters. While the BPF meter maintains accuracy across all pipe configurations, larger pipe diameters are correlated with minor increase in the measurement variability. Therefore, the selection of a suitable pipe diameter ratio (D/d) is essential for maintaining the accuracy of BPF meter. By considering these design aspects, BPF meter could be accurately calibrated to meet the different demands.

Conclusions: The study validated the suitability of BPF meters for accurate water flow measurement in smart farming applications. The variation of the K coefficient across different D/d ratios illustrates the flexibility in adapting the BPF meter for different applications. The results also show that the choice of pipe diameter (D/d ratio) significantly affects the accuracy and applicability of BPF meter. Smaller D/d ratios are more suitable for systems with lower flow rates, while larger ratios are more suitable for higher flow rate systems. Nevertheless, the calibration equation ensures that BPF meter can be effectively used in various irrigation applications.

Practical Application: This study provides a practical framework for the implementation of BPF meter as a viable and cost-efficient alternative to conventional flow measurement devices. BPF meter can be practically applied to enhance water management in smart farming or any irrigation applications. Farmers would be able to monitor and regulate water usage in real-time through the use of BPF meter. Integrating BPF meter with IoT systems would allow precision irrigation to be implemented, optimizing water allocation to crops according to plant water requirements, hence improving productivity, conserving water resources, and providing significant benefits to agricultural systems with limited resources.

Prioritization of Irrigation Construction Projects in Intermontane Plateaus using AHP and FAHP: A Case Study of Lampang and Phayao Provinces

Nattapong Tanakhan — 2025-03-26

Background and Objectives: Delivering irrigation water in intermountain plains differs from the water delivery in river basin plains or plains. In the intermountain plain areas, the topography is similar to hills, alternating high and low slopes. This makes it quite difficult to deliver water to agricultural areas, causing farmers to have problems in farming. Although the government has assisted, due to a limited budget, it has been unable to implement all the desired projects. This study aimed to study and select projects that are ready and necessary. The study area lies in the plain area between mountains in Lampang and Phayao provinces. This case study covered all five projects in the construction plan for fiscal year 2024 of the Royal Irrigation Department.

Methodology: The study employed Analytical Hierarchy Process (AHP) and Fuzzy Analytical Hierarchy Process (FAHP) methods. The analysis was divided into 3 parts: finding the factors affecting the project selection, prioritizing the project, and comparing the results from the two methods. The data were obtained by interviewing the personnel involved in the project implementation. These personnel were executives and experts involved in the construction projects and prioritizing the projects of the Royal Irrigation Department.

Main Results: The results of the weighted values of the main and secondary factors as obtained from AHP and FAHP methods reveal that the main important factors are agriculture and engineering aspects, with AHP’s weighted values of 0.364 and 0.259, respectively, and FAHP’s values of 0.577 and 0.332. The main secondary factors are the area of dry season crop growing that increased after the project, the number of irrigation buildings, water supply, and benefit areas, with weighted values obtained via the AHP method of 0.276, 0.100, 0.101, and 0.100, respectively, and via the FAHP methods of 0.306, 0.111, 0.108 and 0.105, respectively. The consistency ratios (C.R.) of the data are consistent and noted to be reasonable, with the values of less than 0.10. The prioritization results obtained via AHP method are: (1) Mae Wang Operation and Maintenance Project (Mae Pung Weir) On-farm Water Development, Phase 1; (2) Lam Nam Yao - Lower Mae Wang Right Bank On-farm Water Development Project (Khao Son Weir); (3) Mae Tam Reservoir Left Bank Canal Improvement Project; (4) Mae Klang Reservoir On-farm Water Development Project, Phase 2 and (5) Mae Phrik Reservoir (Pha Wing Chu) On-farm Water Development Project, Phase 2, with weighted values of 0.292, 0.238, 0.172, 0.151, and 0.147, respectively. The first and second ranking results by FAHP method were the same as those by AHP; the 3rd and 4th ranks were similar but in the reverse order. The final order result was the same with the following weights: 0.375, 0.318, 0.138, 0.094, and 0.075, respectively.

Conclusions: When comparing the ranking of projects as depicted from the two analysis methods, FAHP method resulted in projects that are already outstanding in some aspects to be even be more outstanding; conversely, the projects with less outstanding aspects become even less impressive. If there is a clear and complete project information, AHP method, which is a more basic method, can be used to arrive at similar results. In this case, the results of selecting the first- and second-ranked projects were the same, no matter which selection methods were used. The first two ranked projects received high priorities because both projects were outstanding in agriculture aspect and could increase the planting area during the dry season, resulting in an increased agricultural production. From engineering viewpoint, these projects also consist of many irrigation buildings, allowing agricultural areas to benefit more from the irrigation system.

Practical Application: FAHP is a suitable alternative in decision-making as it can handle uncertain decisions due to unclear project information. However, if the information is clear and adequately complete, AHP is an effective method, which is simpler for an analysis. The results here reveal the factors affecting the prioritization of irrigation construction projects in the intermontane plateaus. Planning agencies can use the model to analyze rankings of similar agricultural projects, so that projects that benefit communities would receive support, helping farmers benefit and provide sufficient water.