Multiphysics FEM-based Design and Thermo-mechanical Simulation of Domestically Used tuberous food Processing Machine

International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 203 Multiphysics FEM-based Design and Thermo-mechanical Simulation of Domestically Used tuberous food Processing Machine Alexis Malachy Robert and Victor David Okon Department of Mechanical Engineering Technology, Akwa Ibom State Polytechnic, Ikot Osurua, PMB. 1200 ARTICLE INFO ABSTRACT Paper ID: IJASTR68DC0A2B12066 Received: 2025-09-02 Published: 2025-10-05 DOI: https://dx.doi.org /10.5281/zenodo.17 330588 Page No: 203-217 Tuberous root crops such as yam, cassava, and cocoyam are vital staples in Nigeria, yet their traditional manual processing through pounding is laborious, intensive, timeconsuming, and physically demanding. This study applies a Multiphysics finite element method (FEM) approach to the design and thermo-mechanical simulation of a domestically used tuberous food processing machine, with focus on optimizing its processing chamber withe critical site of thermal and structural interactions. The machine comprises a stainless-steel container with shaft–blade assembly and polyethylene insulation for heat retention. Using ANSYS, thermal analyses incorporated internal convection from food heating and external cooling, while static structural simulations evaluated von Mises stress, elastic strain, and total deformation under coupled loads. Mesh models of open and closed chamber designs were refined for accurate predictions. Findings from the study showed that bottom-heated models achieved higher base temperatures of 80.5 °C enabling rapid processing. The heat flux peaked at 0.0186 W/mm² in the localized hotspots but was reduced to 0.0030 W/mm² through design refinements, enhancing uniformity. Equivalent elastic strain, initially 0.0818 mm/mm at chamber–blade interfaces, was minimized to 0.000126 mm/mm after optimization. Similarly, von Mises stress fell from 86.9 MPa in the chamber to 24.3 MPa in blade assemblies, well below the yield strength of stainless steel. The findings demonstrate that FEM-based thermo-mechanical analysis effectively informs material selection and geometry optimization, producing safer, more durable, and energy-efficient machines. Beyond technical performance, adoption of such optimized designs can alleviate manual drudgery, improve food safety, and support food security in agrarian communities. Keywords: Tuberous food processing machine, Finite element method (FEM), Thermomechanical simulation, Multiphysics analysis, Design optimization 1. Introduction Tuberous root crops, such as yam, cassava, and sweet potato, are staple foods in many regions around the world. These crops are typically processed through pounding, a labour-intensive task that requires significant physical effort. To alleviate this burden, the development of tuberous root food-based processing machines has gained attention (Laila et al., 2025; Javed et al., 2025). Nigeria, as a country with a rich agricultural heritage, heavily relies on tuberous root International Journal of Advanced Scientific and Technical Research Available online on http://www.rspublication.com/ijst/index.html ISSN 2249-9954 Cite This Paper : Alexis Malachy Robert and Victor David Okon (2025). " Multiphysics FEM-based Design and Thermo-mechanical Simulation of Domestically Used tuberous food Processing Machine ". INTERNATIONAL JOURNAL OF ADVANCED SCIENTIFIC AND TECHNICAL RESEARCH (IJASTR), vol. 15, no. 5, 2025, pp. 203-217. DOI: https://dx.doi.org/10.5281/zenodo.17330588 International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 204 crops such as yam, cassava, and cocoyam as staple foods. The traditional method of processing these crops involves manually pounding them using a mortar and pestle, which is labourintensive and time-consuming (Hazarika et al., 2025). This study argues for the adoption and improvement of tuberous root food-based processing machines in Nigeria to enhance food processing efficiency, reduce drudgery, and promote economic growth. Tuberous root crops play a vital role in Nigeria's food security and economic development (Onawo & Egboduku, 2025). However, the traditional method of processing these crops poses several challenges. Manual tuberous food processing requires significant physical effort, leading to fatigue and health issues among women, who are primarily responsible for this task (Ojolo, 2024; Onawo & Egboduku, 2025). Additionally, the process is time-consuming, limiting the quantity of food that can be processed within a given period. These challenges hinder the potential of tuberous root crops to contribute to food security and economic growth. A study conducted by Ogiemudia et al. (2016) found that the use of pounding machines increased processing efficiency by 70% compared to manual pounding. This improvement allows for increased food production, which can help meet the growing demand and reduce post-harvest losses. The physical strain associated with manual processing method can lead to musculoskeletal disorders and other health issues. By introducing pounding machines, the physical burden on women can be alleviated, promoting their well-being. Furthermore, the use of machines reduces the risk of injuries caused by accidents during manual processing of tuberous food (Prasetyo et al., 2022; Sypuła et al., 2025). According to a study by Amine et al. (2015), the adoption of pounding machines significantly reduced the incidence of injuries among women involved in food processing. Among the various components of such machines, the tuberous food processing chamber is of paramount importance, as it is the primary site of mechanical and thermal interactions during food processing. To optimize the design and performance of these machines, advanced engineering techniques such as Multiphysics Finite Element Method (FEM) based design and thermo-mechanical simulation have been employed in this study. Multiphysics FEM-based design involves the use of computational models that integrate multiple physical phenomena, such as structural mechanics and heat transfer, to simulate the behaviour of complex systems (Patadia & Sweat, 2025; Alotaibi et al., 2025). This approach allows the analyses and optimization of the food processing machines performance under various operating conditions, taking into account the interactions between different physical processes. In the context of tuberous food processing machines analysed in this study, Multiphysics FEM-based design enables the simultaneous consideration of mechanical stresses and equivalent strains, thermal effects, and material properties, leading to more accurate and comprehensive predictions of machine behaviour (Liu, et al., 2025; Zhao et al., 2025). Thermomechanical simulation, a subset of Multiphysics analysis, focuses on the coupled effects of thermal and mechanical phenomena. In tuberous food processing machines, this type of simulation is particularly relevant due to the heat generated during the in-chamber food processing and its impact on the structural integrity and performance of the machine components. By incorporating thermo-mechanical simulations into the design process, potential issues related to thermal expansion, material fatigue, and overall machine efficiency can be identified and mitigated (Bassey et al., 2023; Ikpe & Bassey, 2023; Siregar, 2025). The focus on thermal, stress, equivalent, and total deformation analysis on the tuberous food processing chamber is justified by several key factors: i. Critical component: The tuberous food processing chamber is the primary site of mechanical and thermal interactions during food processing. It experiences high stresses, temperature fluctuations, and deformations, making it the most critical component for ensuring the machine's overall performance and longevity. International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 205 ii. Stress concentration: The chamber is subjected to high mechanical stresses during operation, particularly in areas where the geometry changes abruptly. Analysing stress distributions helps identify potential weak points and optimize the chamber design to prevent failure. iii. Equivalent stress analysis: By examining the equivalent stress (von Mises stress) in the chamber, engineers can assess the likelihood of material yielding and failure under complex loading conditions, ensuring the chamber's durability and safety. iv. Total deformation: Understanding the total deformation of the chamber under various operating conditions is crucial for maintaining dimensional accuracy, preventing interference between moving parts, and ensuring consistent product quality. v. Material selection: Thermal and stress analyses provide valuable insights for selecting appropriate materials that can withstand the harsh operating conditions within the chamber while meeting food safety requirements. vi. Design optimization: By focusing on these analyses, engineers can iteratively refine the chamber design to improve heat dissipation, reduce stress concentrations, and minimize deformations, leading to enhanced performance and longevity of the machine. By focusing on the thermal, stress, equivalent, and total deformation analysis of the tuberous food processing chamber, more efficient, durable, and safe machines that meet the growing demands of domestic food processing applications can be developed. This approach not only enhances the performance of these machines but also contributes to improved food safety, reduced energy consumption, and increased user satisfaction. 2. Research Methodology Geometry of the tuberous food processing machine consists of a cylindrical barrel (body) which includes a stainless steel container, polyethylene layer housing the steel container as well as shaft and blades components assembly made from stainless steel. The stainless steel had thermal conductivity of 1.51e-2 W/mm·°C, tensile yield strength of 207 MPa and thermal capacity of 4.8e+5 mJ/kg·K. However, the polyethylene material had thermal conductivity of 2.8e-4 W/mm·°C, tensile yield strength of 25 MPa and thermal capacity of 2.3e+6 mJ/kg·K. The polyethylene layer which was found at the base, cover and the cylindrical barrel (body) of the machine served as insulating medium to prevent the escape of heat within the cylindrical vessel. The CAD models (see Figure 1a-b) developed using ANSYS software showcase an open and a closed design of a tuberous food processing machine. Each model features a stainless steel container equipped with blade components, including a shaft barrel and stainless steel blades for efficient processing. The designs incorporate two layers of polyethylene for insulation, enhancing durability and temperature control. The left model presents an open configuration, while the right model illustrates a closed variant, highlighting versatility in food preparation methods. Details of the model geometry as well as the thermal and mechanical properties are presented in Table 1: International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 206 Table 1: Details of the CAD model geometry Object Name Cover Cylindrical Barrel Cylindrical Barrel Cylindrical Barrel Blades Component Blades Component Blades Component Blades Component Blades Component Material Polyethylene Stainless Steel Polyethylene Stainless Steel Polyethylene Length X 82.945 mm 101.6 mm 76.749 mm 72.743 mm 14.847 mm 15.813 mm 14.847 mm 21.911 mm Length Y 7.4577 mm 25.078 mm 79. mm 20. mm 1.8687 mm 2.0322 mm 1.8687 mm 60. mm Length Z 82.945 mm 82.749 mm 76.749 mm 72.743 mm 17.539 mm 18.335 mm 17.539 mm 21.911 mm Volume 2713.2 mm³ 24476 mm³ 79188 mm³ 10250 mm³ 13.173 mm³ 15.426 mm³ 13.173 mm³ 3383.5 mm³ Mass 2.5775e003 kg 2.3252e002 kg 0.6137 kg 9.738e003 kg 1.0209e004 kg 1.1955e004 kg 1.0209e004 kg 3.2143e003 kg Centroid X -138.7 mm -134.08 mm -143.31 mm -134.1 mm -143.33 mm -138.7 mm Centroid Y -36.433 mm -44.517 mm -82.644 mm -111.65 mm -104.12 mm -86.126 mm -74.126 mm -111.12 mm -79.227 mm Centroid Z 67.456 mm 67.469 mm 67.458 mm 67.459 mm 79.122 mm 55.917 mm 78.997 mm 55.792 mm 67.457 mm Moment of Inertia Ip1 0.78583 kg·mm² 18.142 kg·mm² 708.21 kg·mm² 6.1165 kg·mm² 2.0046e003 kg·mm² 2.1354e003 kg·mm² 2.0046e003 kg·mm² 1.1313 kg·mm² Moment of Inertia Ip2 1.5361 kg·mm² 36.161 kg·mm² 673.91 kg·mm² 11.604 kg·mm² 2.0725e003 kg·mm² 2.2312e003 kg·mm² 2.0725e003 kg·mm² 6.2793e002 kg·mm² Moment of Inertia Ip3 0.78588 kg·mm² 20.707 kg·mm² 708.21 kg·mm² 6.118 kg·mm² 7.282e005 kg·mm² 1.0097e004 kg·mm² 7.282e005 kg·mm² 1.1313 kg·mm² Nodes 31026 14392 9939 5614 2159 802 795 2168 1876 Elements 15929 7969 5116 2467 899 318 313 906 898 International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 207 Figure 1: CAD model of a tuberous food processing machine The 3 CAD models depict two variations of a tuberous food processing machine: an open (left) and a closed (right) design. The geometry is defined with a triangular mesh that outlines the cylindrical body and the conical interior surface. The finite element mesh density varies, particularly around the rim and the base. Moreover, triangular meshing is employed, but with an additional lid feature. The mesh is denser at the junctions between components to account for the stresses when the lid is applied, also ensuring a smooth flow of forces across the structure. Both models are designed for efficient simulation of mechanical performance, with the mesh facilitating detailed analysis of structural integrity during operation. Mesh details of the CAD model are presented in Table 2 while the mesh visualization is displayed in Figures 2a-b. Table 2: Mesh details of the tuberous food processing CAD model S/N. Object Name Mesh Information 1 Physics Preference Mechanical 2 T ype Triangular mesh 3 Span Angle Center Medium 4 Initial Size Seed Part 5 Bounding Box Diagonal 162.11 mm 6 Average Surface Area 430.74 mm² 7 Minimum Edge Length 0.11524 mm 8 Error Limits Aggressive Mechanical 9 Target Element Quality Default (5.e - 002) 10 Smoothing Medium 11 Inflation Option Smooth Transition 12 Transition Ratio 0.272 13 Maximum Layers 5 14 Growth Rate 1.2 15 Inflation Algorithm Pre 16 Inflation Element Type Wedges 17 Rigid Body Behavior Dimensionally Reduced 18 Sheet Body Method Quad Dominant 19 Sweep - able Body Method Sweep 20 Nodes 62052 21 Elements 31533 International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 208 Figure 2: Mesh visualization of the tuberous food processing CAD model 2.1. Thermal and Structural Analysis This is the stage where thermal and mechanical loads are applied. The thermal analysis involved solving for temperature distribution, applying flux convergence of 1.e-004, solver tolerance of 1.e-007 W/mm, over relaxation of 0.1, Hemicube resolution of 10 as well as maximum iteration of 1000. The thermal boundary conditions included initial temperature of 22 °C (uniform), internal convection (food heat) including: i. Faces: 18 ii. Coefficient: 5e-4 W/mm²·°C (500 W/m²·°C) iii. Ambient Temperature: 80 °C However, the external convection (air cooling) included: i. Faces: 13 ii. Coefficient: 1e-5 W/mm²·°C (10 W/m²·°C) iii. Ambient Temperature: 22 °C For the static analysis, thermal results was applied as input for von mises stress, equivalent strain and deformation analysis. Details of the static structural loads are presented in Table 3: International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 209 Table 3: Details of static structural loads Object Name Force Force 2 Pressure Fixed Support Cylindrical Support Displacement State Fully Defined Scope Scoping Method Geometry Selection Geometry 2 Faces 1 Face Definition Type Force Pressure Fixed Support Cylindrical Support Displacement Define By Vector Normal To Components Applied By Surface Effect Magnitude 8. N (ramped) 15. MPa (ramped) Loaded Area Deformed Radial Free Axial Free Tangential Fixed Coordinate System Global Coordinate System X Component Free Y Component 1. mm (ramped) Z Component Free Interpolation Type Mechanical Results Transfer Acceleration - Y Direction X Component 0. mm/s² (ramped) Y Component - 9806.6 mm/s² (ramped) Z Component 0. mm/s² (ramped) 3. Results and Discussion Figures 4a-b depicts two simulation profiles of steady-state thermal temperature distributions of a cylindrical tuberous food processing chamber, modelled as a meshed profile. Figure 4a shows a bottom-heated configuration with a temperature gradient decreasing upward, while Figure 4b illustrates a top-heated profile with the gradient decreasing downward. These distributions suggest heating strategies, such as conduction from the base (see Figure 4a and convection from the top in Figure 4b, which could optimize processing for tuberous foods by ensuring even cooking, sterilization, or drying while minimizing energy loss or material stress. In Figure 4a, the maximum temperature of approximately 80.5°C at the bottom benefits efficient heat transfer for rapid initial processing, implying faster cooking times and better pathogen elimination in denser tuber bases, but risks overheating sensitive materials or uneven doneness if not monitored, potentially leading to nutrient degradation. The minimum of about 51.1°C at the top implies energy conservation by avoiding over-heating unused space, beneficial for cost-effective operations, though it could result in incomplete processing in upper International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 210 regions, necessitating stirring or redesign for uniformity. However, in Figure 4b, the peak temperature of about 80°C at the top supports uniform top-down penetration for delicate surface treatments, implying improved flavour retention and reduced scorching in tubers, but may cause thermal fatigue in lid components over time. The minimum of approximately 39.9°C at the bottom benefits safer handling post-processing by quicker cooldown, reducing burn risks, yet implies potential under-processing at the base, which could compromise food safety if microbial activity persists in cooler zones. Figure 4: Steady-state temperature distribution on tuberous food processing chamber The ANSYS simulation profiles in Figures 5a-b indicate steady-state total heat flux distributions on a meshed cylindrical chamber for tuberous food processing. Figure 5a presents a higher-flux scenario with a maximum of 0.018579 W/mm² concentrated near the chamber's top/outer edges (red zones), tapering to a near-zero minimum (3.789e-16 W/mm²) at the base/inner walls (blue zones), indicating uneven heat input dominated by localized sources. However, Figure 5b, from a later simulation iteration, exhibits reduced overall heat flux with a maximum of 0.00301 W/mm² (still at outer edges but with a very low intensity) and a minimum of 5.820e-16 W/mm², suggesting improved uniformity and lower energy gradients across the chamber. One of the advantages offered by maximum heat fluxes of 0.018579 W/mm² in Figure 5a and 0.00301 W/mm² in Figure 5b includes targeted heating for efficient processing (faster moisture evaporation in tubers at hotspots), reducing overall energy use by focusing flux where needed. However, the peak values in Figure 5a risk thermal hotspots causing uneven cooking, nutrient degradation, or chamber material stress; whereas, the decline in Figure 5b implies minimized risks, enhancing food quality and equipment longevity as well as reduction in operational costs. International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publication, [email protected] 211 Figure 5: Steady-state total heat flux distribution on tuberous food processing chamber Figures 6a-b represents ANSYS simulation profiles illustrating the equivalent elastic strain distribution on a meshed cylindrical chamber. This includes a barrel body and internal blade component assembly, designed for tuberous food processing. Figure 6a depicts a high-strain scenario with maximum of 0.081778 mm/mm concentrated at equivalent elastic strain points (red zones, likely at the interface between the dissimilar materials of stainless steel and polyethylene), decreasing to a minimum of 2.526e-9 mm/mm in low-strain areas (blue zones), indicating potential deformation hotspots from operational forces. Figure 6b indicates a significantly reduced strain profile with a maximum of 0.0001259 mm/mm occurring at the joint between the shaft and the blade root. Judging from the colour distribution, this suggests an optimized design iteration with more uniform distribution and minimal strain concentrations, possibly after material or geometry adjustments. It should be noted that the colour distribution with red implies peak values while blue represent minimum values. These profiles look safe, translating to vibration reduction, better energy transfer for uniform food processing, enhanced durability, with long-term performance and minimal deformation. The plot in Figure 6c quantifies equivalent elastic strain metrics across components, displaying a high maximum value of 8.18E-02 mm/mm on the cylindrical barrel alongside its average of 1.03E-02 mm/mm, contrasted with much lower values for the blade component (maximum 1.26E-04 mm/mm and average 9.15E-06 mm/mm). This visualization highlights the barrel as the primary stress bearer, likely under greater operational loads, and present design disparities where the blade experiences negligible strain, aiding in targeted material optimizations for the assembly