ANSYS Model Research Articles

Investigation of the steady state subcooled boiling regime in the hot subchannel of a VVER-1200 reactor core: a CFD analysis

A Computational Fluid Dynamics (CFD) analysis is carried out on a three-dimensional subchannel representing the most intensive fuel assembly to simulate the thermal-hydraulic performance of the VVER-1200 hot channel under steady-state operation. It is found that, subcooled boiling is predicted for both the rated and the conservative operational parameters with the intensity of bubble generation found to be higher for the conservative scenario compared with the rated one. The predicted boiling phenomenon at the cladding surface may result in the formation of deposits, and pits, and may impair the strength of the fuel elements, and increase the inhomogeneity in fuel burnup. Therefore; a thorough investigation of the predicted boiling regime is required to shed light on the development of this phenomenon in a typical reactor subchannel using CFD tools. The CFD work conducted in this work is based on the Eulerian multiphase model in ANSYS in conjunction with the RPI wall boiling model. The developed model has been validated against other one-dimensional models found in the literature. The variation of mass-averaged quantities (across the channel) along the subchannel generally agrees with the 1D models, which builds confidence in the modeling approach. Contours showing the spatial variations of temperatures, vapor void ratio, as well as heat fluxes are presented. Profiles of the different components of heat flux during boiling are presented. It has been found that the heat flux variations during boiling pass through three distinct regimes. In the first, a steady increase in quenching and evaporation heat flux is observed, while convective heat flux declines. In the second regime, the quenching and evaporation heat fluxes plateau with a slight decrease, while the convective heat flux becomes zero. This signifies that the outer clad surface is largely covered with vapor bubbles and the only heat transfer mechanisms are due to quenching and evaporation. During the last regime, quenching and evaporation heat fluxes decline due to the decline of the imposed heat flux at the clad surface, and hence convective heat transfer starts to increase. In addition, profiles of the mass-averaged coolant temperature, void fraction, and outer clad surface temperatures along the hot element underrated and conservative operating conditions are also generated.

Static analysis of wind blades based on weight loads to the gravitation and the centrifugal forces Using Finite Element

Static analysis of wind turbine blades that convert kinetic energy using wind to electrical power has been analyzed using Ansys model. The geometry was imported in ANSYS workbench 2020R1, where the material was changed to Epoxy E-Glass Wet. The mesh independence that occurred at 800 and 600 element sizes and an element size of 800 was chosen for subsequent static analysis. The static analysis shows that the total deformation and von Mises stress of the wind turbine blade was improved at both the vertical position and the horizontal position by 40.0% and 38.61%, respectively. Besides, the static analysis showed an almost linear mode shape increased from mode lines. Nevertheless, Campbell's diagram showed that resonance vibration occurred at an amplitude of 5.5x106Pa with a corresponding frequency of 5Hz, which gave a rotational speed of 262.4x106 rpm. This shows that the impulse force is better applied in wind turbine blade transient analysis at a lower von Mises stress to attain a quicker damping response steady-state, which favors wind turbine blade analysis. Overall, the wind turbine blade is better designed at a vertical position to allow better deformation stress at a static position. Conversely, the von Mises stress showed 44.64% and 38.61% at horizontal and vertical positions. This also agrees with static total deformation, since stress is better managed at a lower percentage range.

Developing Programs for Converting MIDAS GEN to ANSYS Models Based on Python

The reasonableness and accuracy of engineering design are often assessed through the use of a variety of structural design analysis software, which are then compared and verified. However, it is challenging for a single analysis software to meet the diverse and complex design requirements. In order to meet the specific engineering requirements, it is necessary to convert the MIDAS result model into an ANSYS structural model and conduct a nonlinear analysis and simulation in ANSYS. Nevertheless, the existing interface is unable to facilitate direct conversion of the model. Accordingly, this paper presents a Python-based ANSYS APDL program that enables the complete conversion of MIDAS GEN structural models to ANSYS finite element models. The program is capable of converting a range of data, including material, section, element, connection, load, node mass, constraint, time history function, and so forth. The program is capable of converting specific connection units, including elastic and general connection units. Additionally, the beam-column section direction, beam end freedom release, rigid element, and special anti-rocking structure of the structure can be considered. Ultimately, the theatre model is transformed. Following a comparison of the analysis results, it was found that the mass and mode of the model before and after the transformation were essentially identical. The maximum error of the first six orders of the structure is 2.95%, with the structural displacement under gravity load remaining essentially unchanged. The research and analysis demonstrate the accuracy and reliability of the MIDAS GEN conversion ANSYS program. The conversion program significantly reduces the time required for direct modeling in ANSYS, enhancing work efficiency. The study has considerable practical significance for the seismic sway design and analysis of buildings based on vibration isolation design.

Optimizing Sheet Metal Formation through Advanced Hydroforming Simulation Technique

In this study, we investigate into the simulation of sheet metal hydroforming for crafting the cap of the axle-hub of a tip trailer within our manufacturing facility. This cap serves a crucial role in safeguarding wheel bearings from the detrimental effects of dust, sand, and dirt. The motivation for this work arises from the challenges encountered during the fixation of a conventional dust cap, which often falls off when subjected to pressure or threading, particularly when the tractor is in motion. The innovative approach pursued in this research involves the utilization of lightweight aluminum sheet metal for cap production, owing to its facile formability. The cap design incorporates four evenly distributed holes around its circumference and secures to the flange using screws. Prior to the manufacturing phase, a simulation of the cap-forming process was conducted using ANSYS Model 15, a computer-aided engineering program. The necessary models were crafted in CATIA, a computer-aided design program, streamlining the entire process to enhance efficiency, reduce costs, and minimize manpower requirements. The simulation encompassed three different thicknesses (1 mm, 2 mm, and 3 mm) for two distinct aluminum alloys, namely 1100 and 5652. The objective was to discern the optimal alloy for the forming process. Essential mechanical properties, including ultimate tensile strength, modulus of elasticity, and yield stress, were input into the ANSYS program to accurately reflect the materials' behavior during forming. The outcomes of our investigation revealed that aluminum alloy 5652 outperformed 1100 in terms of formability. The former exhibited a forming pressure of 300.2 MPa, while the latter required 298.3 MPa for the same forming depth (40 mm) across all three thickness variations. Additionally, the study demonstrated that 5652 is not only more efficient but also safer and more resilient than 1100.

Extracting non-equilibrium material properties in visco-hyperelastic polymers based on analytical stress solution

This study extracts non-equilibrium material properties in the visco-hyperelastic polymers using an analytical stress solution. At first, the analytical stress solution of visco-hyperelastic polymers is obtained from finite-strain creep test data based on the generalized Maxwell’s rheological model. The solution uses the low-computational-cost exponential generalized pseudospectral method and analytically brings the stress components in terms of time and unknown non-equilibrium material properties of Maxwell’s elements. The solution invokes the Ogden hyperelastic model for the elastic element of the generalized Maxwell’s model. The exponential generalized pseudospectral method, based on exponential–rational Lagrange functions suitable for the semi-infinite time interval [Formula: see text] and the rational Chebyshev roots as the collocation points, is applied to derive the stress components. The non-equilibrium properties are derived by minimizing a residual, which is obtained by making the derivatives of the residual in terms of the non-equilibrium properties as zero. Notably, the proposed analytical method requires a small number of exponent–rational Lagrange basis functions and collocation points. Besides, the proposed method does not require integration, discretization, or linearization. Two case studies are considered: the moderate-stretched ETFE polymer with the neo-Hookean model as the elastic element and the large-stretched rubber with the six-parameter Ogden hyperelastic model as the elastic branch. The results are validated using uniaxial creep modeling in ANSYS and available reports in the literature.

NUMERICAL MODELING OF TWO-PHASE HEAT TRANSFER DURING EVAPORATION AND CONDENSATION INSIDE A SOLAR STILL

This research presents a comparative analysis of two solar still configurations utilizing the ANSYS 2023R2 software package for computational fluid dynamics (CFD) simulations. The study employs the Volume of Fluid (VoF) model to simulate phase transitions between liquid and vapor, specifically focusing on vaporization processes. It is important to note that the VoF model used in this study primarily serves to visualize vaporization, with its numerical results aligning with theoretical expectations rather than providing practical applications. The relevance of this research is underscored by the global drinking water crisis, which drives the need to enhance the efficiency of desalination systems. Solar distillation is recognized as one of the most environmentally sustainable methods for producing clean water, making it an appropriate focus for this investigation. The primary objective of this work is to conduct a numerical analysis of the solar still, compare the performance of two different configurations, and evaluate potential modifications to improve the system's efficiency. The study simulates heat transfer processes within the distiller, the distribution of vapor volume fractions, and temperature variations over time. The findings indicate that the dual-slope configuration outperforms the single-slope configuration in terms of efficiency and productivity. Additionally, the research provides insights into the physical processes occurring within the distiller and identifies potential areas for further refinement of the system's modeling in ANSYS.

A Novel Method for Estimating the Thermal Performance of Multi-Block Wall Systems Using Thermal Impedance Z-Value under Transient Uncontrolled Heat Transfer Conditions

Climate change is one of the biggest challenges today. An increasing population accelerates the construction of concrete houses and the use of air conditioners, thereby leading to an increase in energy consumption. When the walls of buildings are well-designed and insulated, energy consumption can be reduced. Therefore, it is important to measure the thermal performance of wall systems accurately. The existing traditional methods of measuring R- and U-values provide acceptable solutions for steady-state controlled, uncontrolled or transient state-controlled conditions. However, a need to develop a novel approach for transient state-uncontrolled realistic conditions has been identified. The present study involves both experimental and numerical investigations. An in situ model room with dimensions of 1.60 m × 1.73 m × 1.50 m was built for the experimental work, and a series of experiments were conducted. For numerical work, two models using Ansys Fluent 2021/2022 and MATLAB Simulink 2021/2022 were developed. The real-time experimental data were fed into numerical models to predict the thermal behavior of the wall system. The results include the evaluation of a concept called ‘Time-Lag’ for all three models. ‘Time-Lag’ is the time taken for the heat energy to flow across the wall system. The Time-Lag for the experimental model was 8 h 45 min, while for MATLAB and Ansys models, it was 8 h 22 min. (average) and 7 h 30 min, respectively. Minor variations validate the accuracy of the numerical models. Further, a novel method using a new parameter in building systems called ‘thermal impedance Z-value’ was developed to estimate the real-time thermal performance of walls using MATLAB Simulink. The Z-value measures the ability of a wall system to resist the flow of heat (thermal resistance, R-value) combined with its ability to store heat energy (thermal capacitance, Cth-value). It is evaluated for steady-state and dynamic (transient) systems. For the steady-state system, the Z-values on the outer and inner walls were 18.2683 K/W and 18.6761 K/W, respectively with a minor difference of 0.4078 K/W at the end of 72 h. For the dynamic system, the Z-value did not reach a constant value and fluctuated in a particular pattern during 24 h of the solar cycle with average values of 3.2969 K/W on the outer and 1.2886 K/W on the inner walls at the end of 72 h, thus presenting more accurate and realistic thermal performance results of a wall system.

CFD Modelling of Swirling Device to Study Bend Erosion Rate at Different Bend Angles in Pneumatic Conveying System

Bend Erosion problems were found mostly common in pneumatic conveying plants. Swirling of particles before striking the bend has been noted as the best solution to minimize bend erosion rate. CFD k-w model in Ansys was applied to analyze mild steel bend erosion in the pipeline by pneumatically conveyed particles with a motor-operated swirling device. A part of the pipe before the bend is rotated at different velocities in different elbow geometries from 15° to 90° elbows. A combination of Eulerian and Lagrangian methods were utilized to track particles. Mathematical modelling of the swirling of particles on bent surfaces is taken into consideration with different elbow angle. The bend erosion rate was mitigated due to the swirling of particles. Different velocities and parameters are taken to evaluate the results. At different bend angles erosion rate is different and the swirling device minimizes the bend erosion rate.

ENGINEERING OF LIQUID-GAS EJECTOR USING NUMERICAL SIMULATION

The article deals with the development and application of the technology of injection of low-pressure associated petroleum gas (APG) into the reservoir through the reservoir pressure maintenance system (RPMS) in connection with the entry into force of the Russian government decree on the mandatory utilization of 95 % of produced APG. The technology under consideration, the key element of which is a liquid-gas ejector (LGE), makes it possible to achieve this level with minimal investment, in the shortest possible time and to stop flaring APG at flares remote from the central oil and gas treatment facilities of oil and gas production facilities. LGEs have a relatively simple and reliable design due to the absence of moving elements.At present, there are known LGEs of classical designs, in which the level of hydrodynamic losses can reach 40–60 %. High hydrodynamic losses make it inexpedient to use such ejectors at small fields operated at a late stage of development, remote from the central oil and gas treatment facilities, due to the limitations of the existing equipment complex and the allowed operation mode of the injection well stock. To ensure the possibility of including LGE in the RPM system it was required to develop a new design of LGE, allowing to reduce hydrodynamic losses up to 30 %, as well as to ensure the maximum possible percentage of APG utilization. The article is devoted to the development, calculation of geometry and operating mode of LGE using numerical modeling in ANSYS environment.Modeling of the flowing part of the main elements of LGE (confuser nozzle, diffuser throat and gas channel width) at different values of parameters directly affecting the level of hydraulic losses is carried out. The results of calculations of numerical simulation of LGE allowed to optimize the dimensions of the internal geometry of LGE, thus it was possible to develop a new device for the required initial data, which will reduce the level of hydraulic losses up to 30 % and ensure the involvement of the maximum volume of gas in the RPM system.

Energy absorption and impact response of ballistic resistance laminate

Abstract High-speed impact performance has significantly expanded over the past few decades. The target response based on the impact conditions has been more difficult to visualise and evaluate. In this article, Ansys model analysis has been used to measure, visualise, and predict the projectile and target responses of Kevlar® (K) and Ramie® textile-reinforced unsaturated polyester resin (UP) matrix. The laminate thickness threshold was detected experimentally based on the highest stress intensity factor and energy release rates. Furthermore, tensile strength and bending of the laminate were found. The impact conditions have a significant impact on the target response; thus, an explicit dynamic analysis was used to visualise the impact response based on the number of target fixed supports (FSs). Two FS (2 FS) target absorbs 11% more energy than four FS (4 FS) target. Additionally, the target size has a major effect on the projectile and laminate responses, and a successful arrest of the projectile was detected in both cases. The smallest targets with 2 FS have the highest and wider response, where a successful change in the projectile trajectory was obtained.

Validating ANSYS Heat Transfer Models Using Experimental Data Analysis of Two Phase Change Materials with Differing Melting Temperatures

Phase change materials are becoming more and more popular as viable options for improving the thermal performance and energy efficiency of a variety of applications, especially in innovative building envelope designs. In this paper, experimental data from two different phase change materials with differing melting temperatures (21°C and 28°C) are used to validate numerical system heat transfer models. The experimental setup included a heat flux apparatus, which was utilized to ascertain average temperature and heat flow changes over time during both heating and cooling phases for both phase change materials. The data obtained from the experiments were utilized to generate ANSYS Fluent simulation models replicating the experimental setup. The parameters and boundary conditions for the models can be assigned in several ways within ANSYS Fluent software. Consequently, two simulation models were created: one integrated the thermal and physical properties of the experimental setup's system components, while the other utilized the measured heat-flux values over time from the experiments as an input source for calculating average temperatures within the phase change material. The average temperature data from both simulation and experimental results were compared to validate both ANSYS models. By aligning the simulated results with the experimental data, the accuracy and reliability of the numerical models have been established in predicting the thermal behaviour of the two phase change materials. The two numerical system heat transfer models developed in this study serve as valuable tools for conducting further analysis and optimization of systems based on phase change materials. This research highlights the significance of phase change materials in enhancing the thermal performance of building envelopes, particularly in solar energy applications.

Exploring key factors affecting the ultimate compression capacity of Unbonded Steel-mesh-reinforced Rubber Bearings

To address bearing-sliding damage in highway bridges during seismic events, the Unbonded Steel-mesh-reinforced Rubber Bearing (USRB) was developed. This novel bearing employs flexible, high-strength steel wire meshes as reinforcement, enhancing lateral deformation capacity and reducing bearing-sliding risk. Recent seismic specifications increased the bearings' vertical design load to 30 MPa, where existing bearings with flexible reinforcements (e.g., fiber-reinforced bearings) fail to meet this standard. Hence, for the first time, our study thoroughly investigated the ultimate compression capacity of USRBs and the key factors influencing the capacity. Through ultimate compression tests on full-scale prototypes, we demonstrated that USRBs can comply with heightened seismic requirements, with primary failure attributed to the tensile failure of the steel mesh reinforcement. These tests were complemented by 3D finite element modeling in ANSYS, employing the LINK180 elements for mesh reinforcement and defining the ultimate capacity as the point at which reinforcement stress reached tensile strength. This particular modeling approach, validated against experimental data, can accurately predict the ultimate compression capacity and the force-deformation response of USRBs. A comprehensive parametric analysis, using the validated modeling approach and an advanced statistical method LHS-PRCC, was conducted to identify the key factors influencing the compressive capacity, including bearing geometric parameters (i.e., bearing width, the second shape factor, and rubber layer thickness), steel-mesh configuration characteristics, and steel-mesh material properties. Our findings emphasize the significance of rubber layer thickness, steel mesh weight, and steel wire tensile strength and strain in influencing the USRBs' ultimate compression capacity. Based on these key factors, an empirical equation for the ultimate compression capacity of USRBs was established to guide the optimization design of USRBs. This study not only fills the gap in USRB's performance under extensive compression but also provides a foundation for future optimization of these bearings to enhance their performance in bridge engineering.

Research on key technology to determine the exact maximum allowable current-carrying ampacity for submarine cables

The maximum allowable current-carrying ampacity (MACCA) of a photoelectric composite submarine cable in its design phase is usually patterned considering the weather. However, variations in sea temperature, the uncertainty of the cable's material parameters and the laying environment of the cable greatly influence its CCA. The impact of these factors can damage the cable, regardless of its quality. For this purpose, this paper proposes a developed iterative parameters correction method (IPCM) based on Chord principles, to determine the exact MACCA by means of finite element method (FEM). Different optical fiber temperatures of the cable are collected using Brillouin Optical Time-Domain Analysis (BOTDA); together with the material parameters of the cable, they are modeled in ANSYS modeling software. Then, the proposed approach is conducted before determining the exact MACCA. Results obtained from experiments performed on different data groups show that the mean error rate obtained with the proposed approach is just about 3.78, while that of the other four recent approaches, including AP1, AP2, AP3 and AP4 is about 4.59, 3.96, 4.13 and 4.80, respectively.

Microstructure, Mechanical Properties, and Heat Distribution ANSYS model of CP Copper and 316 Stainless Steel Torch Brazing

Microstructure, Mechanical Properties, and Heat Distribution ANSYS model of CP Copper and 316 Stainless Steel Torch Brazing

Numerical modeling of the funnel multiphysical flow of fresh self-compacting concrete considering proportionate heterogeneity of aggregates

Filling ability is one of the prominent rheological properties of the self-compacting concrete (SCC), which has been studied in this research work deploying the functional behavior of the concrete through the studied funnel apparatus using the coupled ANSYS-SPH interface. Seven (7) model cases were studied and optimized. The aim of this numerical study is to propose a more sustainable mix of coarse and fine aggregates proportion that allows for most minimum flow time to enhance a more efficient filling of forms during concreting. The maximum size of the coarse aggregates considered is 20 mm and that of the fine aggregates is below 4 mm. The Bingham model properties for the multiphysics (SPH)-ANSYS models’ simulation are; viscosity = 20 ≤ μ ≤ 100 and the yield stress = 50 ≤τ0≤200\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\le {\ au }_{0}\\le 200$$\\end{document}, standard flow time, t (s) ranges; 6 ≤ t ≤ 25 and the funnel volume is 12 L. The minimum boundary flow time, which represents the time it takes for the SCC to completely flow through a specified distance, typically measured in seconds was modeled for in the seven (7) model cases. The second case with 40% coarse mixed with 60% fine completely flowed out in 16 s, thus fulfilling the minimum flow time. This minimum flow time was considered alongside other relevant parameters and tests, such as slump flow, passing ability, segregation resistance, and rheological properties (stresses), to comprehensively assess the filling ability of SCC in this model. By considering these factors and the optimized mix (40%C + 60%F:16s), engineers and researchers can optimize the SCC mix design to achieve the desired flowability and filling performance for their specific construction applications. The multiphase optimized mix was further simulated using the coupled interface of the ANSYS-SPH platform operating with the CFX command at air temperature of 25 °C. The results show energy reduction jump at the optimized flow time. Ideally, the mix, 40%C + 60%F:16s has been proposed as the mix with the most efficient flow to achieve the filling ability for sustainable structural concrete construction.

Warping Torsion in Sandwich Panels: Analyzing the Structural Behavior through Experimental and Numerical Studies.

Recently, there has been a growing interest in the use of sandwich panels that, beyond handling well-known bending stress, can withstand torsional stresses. This is particularly relevant for wall applications when the panels are equipped with photovoltaic or supplemental curtain wall modules. This research article presents a detailed exploration of the structural behavior of eccentrically loaded sandwich panels, with a specific focus on warping torsion. Experimental and numerical studies were conducted on polyisocyanurate (PU) core sandwich panels, commonly employed in building envelopes. These studies involved various dimensions and material properties, while omitting longitudinal joints. The experimental study provided essential insights and validated the numerical model in ANSYS. Enabling parametric variation, the numerical analysis extends the analysis beyond the experimental scope. Results revealed a high degree of correlation between experimental, numerical, and analytical solutions, regarding the rotation, as well as the normal and shear stress of the panel. Confirming the general applicability of warping torsion in sandwich panels with certain limitations, the study contributes valuable data for applications and design of eccentrically loaded sandwich panels, laying the foundation for potential engineering calculation methods.

In-plane and out-of-plane vibration analysis of laminated composite frames with warping effects

This paper addresses the free vibration analysis of a general planar frame structure, consisting of an assembly of laminated composite beam members. A mathematical model is established for the beams by introducing a novel displacement field, which encompasses the influence of shear deformation, rotary inertia, material coupling, warping phenomenon, as well as in-plane and out-of-plane deformations. By incorporating these various factors, a comprehensive representation of the beam's behavior is achieved. The continuity equations for displacements and rotations of two adjacent members are formulated to derive the equations for the entire frame structure. The assembled equations are solved using the Finite Element Method (FEM). The numerical results obtained are compared with existing results in the literature and new results from 3D models in ANSYS. The present results for torsional modes are closer to the ANSYS results than the results of previous studies. An extensive analysis is performed to investigate the impact of various parameters, including stacking sequence, frame angle, relative frame length, and anisotropy ratios on the system response.

Experimental investigation and numeric modelling of the impact performance of basalt fiber reinforced geopolymer concrete

Geopolymer concrete (GC) has been found to have better results than Portland cement concrete (PCC), including lower carbon dioxide emissions, higher compressive strength, and greater durability. The study aims to determine the effects of basalt fiber on GC due to the impact caused by the sudden loading effect. Samples were prepared with different mixing ratios for the experimental process, with PCC used as the control sample. Basalt fibers were added to the samples in three different ratios based on optimal mixing ratios determined through physical and mechanical tests, such as UPV (Ultrasonic Pulse Velocity), compressive strength, and flexural strength. Subsequently, fibrous samples were analyzed using SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy). A drop-weight experiment was conducted on GC plates measuring 50×50×5 cm, which contained two different fiber ratios that yielded the best mechanical and physical properties. The results were analyzed using numerical modeling methods. No changes in content were made. The sample with the highest impact resistance was found to be the 2% basalt fiber-reinforced GC, with a displacement value 21.21% lower than PCC. The language used is clear, concise, and objective, with a formal register and precise word choice. The text follows a logical structure with causal connections between statements and adheres to conventional academic formatting and citation styles. The ANSYS modeling results indicated an 89.63% similarity with the experimental data regarding the displacement values. Additionally, the study demonstrated that the inclusion of basalt fiber additives enhances the impact resistance of geopolymer concrete. Furthermore, numerical modeling can predict the impact behavior of concrete to a significant extent, eliminating the need for experimental processes.

Ratcheting Simulation of Additively Manufactured Aluminum 4043 Samples through Finite Element Analysis

This study presents a finite element-based ratcheting assessment of additively manufactured aluminum 4043 samples undergoing asymmetric loading cycles. The Chaboche material model in ANSYS was utilized and the effects of mesh and element type were examined. Different element numbers were used in a thorough convergence study to obtain independent meshing structures. The coefficients of this model were defined through stress–strain hysteresis loops determined from the strain-controlled tests. The backstress evolution and the corresponding yield surface translation in the deviatoric stress space were discussed as three different mesh elements of linear brick, quadratic tetrahedron, and quadratic brick were adopted. The magnitude of backstress was affected as different element types were employed. The first-order brick elements resulted in the highest backstress increments, while the lowest backstresses were determined when quadratic brick elements were taken. Backstress increments are positioned in an intermediate level with the use of quadratic tetrahedron elements. The choice of the element type, shape, and number influenced material ratcheting response over the loading process. The use of quadratic brick elements elevated the simulated ratcheting curves. The quadratic tetrahedron and linear brick elements, however, suppressed ratcheting level as compared with those of experimental data. The closeness of the simulated ratcheting results to those of the measured values was found to be highly dependent on these finite element variables.

Analysis of Indonesia’s Railway Track Structure Behavior Under Double-Stack Freight Train Loading

The growing number of freight transported using railway transport is massive. Indonesia targeted 995,500,000 tons of freight transported using the railway mode. Double-stack train is one solution to increase thefreight tonnage of the train without adding the number of operations of the train. The 3D ANSYS model ismade to see the structural behavior of railway tracks under the double-stack train load using 1067 mm and 1435 mm gauge from Indonesia’s railway track regulation. It was also modeled with several speeds to observe its influence on the structure. It is known that in all output parameters of deformation, stress, and strain, the 1435 mm gauge actsbetter for the structure than the 1067 mm gauge. The subgrade service life also became longer in the 1435 mm gauge structure. Lower speed also gives a better impactonthe structure of the track and possible to give longer service life for subgrade.Further research isneeded to observe the railway track structural behavior in cyclic loading and the possibilityofreinforcing the subgrade. The lab-scale test also needed to validate the analysis.