Element Analysis Research Articles

Design and Performance Analysis of A Linear Switched Reluctance Motor Considering End Effects

Introduction: In recent years, linear actuators have gained significant attention due to their ability to provide direct linear movement without the need for motion transformation devices. One significant challenge in the design and modeling of linear actuators is the occurrence of longitudinal end-effects. The finite length of the translator stack in linear actuators causes an unbalanced phase force, leading to discrepancies between the phases at the end and center of the actuator. Neglecting these end-effects can lead to inaccuracies in the actuator's performance and control. Methods: The objective of this study is to develop a comprehensive approach for the design, sizing, and modeling of the actuator to ensure optimal performance. An energy conversion procedure calculates the thrust force and determines the actuator's geometrical parameters. A numerical model based on the finite element method is developed to analyze the actuator's magnetic behavior and establish its characteristics. Furthermore, a thorough analysis of the end effect is conducted using two-dimensional finite element analysis. Results: To accurately capture the actuator's dynamic response and enable precise control, a mathematical model is formulated, incorporating the nonlinear behavior of inductance and incorporating the end effect factor. The proposed model demonstrates high accuracy and provides a solid foundation for the control of the linear switched reluctance actuator. Conclusion: Overall, this study contributes to the advancement of direct drive systems for industrial applications by providing a detailed design procedure and an accurate modeling approach for the linear actuator, enabling more efficient and precise control strategies.

Finite element analysis method for the sliding cable analysis: The sliding variable method

A sliding cable structure is typically characterized by uncertainty of sliding and complexity of friction at the cable-strut joints, which makes accurate and efficient analysis difficult. In this study, we have proposed the sliding variable method, to simulate the cable sliding process considering friction equivalently and analyze the internal force and deformation response at the equilibrium state quickly and accurately. The sliding variable method takes the sliding vector of the cable at cable-strut joints as the basic variable, extracts the slippage stiffness matrix and establishes the cable force balance equation to solve the sliding vector, and simulates the change of cable original length and cable force by applying equivalent temperature load. In this paper, first, the basic principles and calculation procedures of the sliding variable method without considering friction, are discussed in detail to simulate frictionless slip of continuous cable, using with roller-type cable-stayed joints. as an example. On this basis, a calculation model incorporating the effects of friction is analyzed, a method to judge the sliding situation and balance relation of cable-forces is revealed, and the calculation principle and steps of the method are further deduced. Meanwhile, choosing a multi-joint cable–pulleys model as an example, the accuracy and rationality of the sliding variable method with and without considering friction are verified respectively. This method requires a conventional finite element calculation and second calculation alternately. Finally, to improve the practicability and computational efficiency of the sliding variable method, a macro document was compiled using the secondary development function of ANSYS parametric programming language (APDL) according to the basic framework of the sliding variable method. The frictional sliding behaviors in two typical engineering cases, a cable girder and a prestressed fish-belly girder on a foundation pit, are analyzed by using the compiled macro document in finite element program. The results show that the compiled macro document can be both accurate and efficient in calculating and analyzing cable sliding problems and can be easily popularized and applied in engineering practices.

Electromagnetic Propagation Characteristics of Submarine Cable Detection With Finite Element Analysis

Electromagnetic Propagation Characteristics of Submarine Cable Detection With Finite Element Analysis

Experimental and numerical investigation of novel triangular headed one-sided bolted T-stub connections

The reliable one-sided bolts constitute a vital component of fully bolted joints in demountable steel structures. In this study, an innovative triangular headed one-sided bolt (THOB) based on the traditional hexagon headed bolt (HHB) was proposed, and the tensile performance of T-stubs using the THOBs has been investigated through experimental and numerical approaches. Monotonic tensile tests were performed on 25 THOB bolted T-stubs to analyze the failure modes and load-carrying performance of the specimens. The test results disclosed that, beyond the three typical failure modes stipulated in the Eurocode 3, the specimens exhibited a characteristic failure mode, namely, limit groove pull-off failure. Finite element models, validated by the test results, were employed for the parametric analysis to compare the load-carrying performance of THOB bolted T-stubs with that of HHB bolted T-stubs. The finite element analysis results indicated that the average ratio of the plastic load-carrying capacity of THOB bolted T-stubs to HHB bolted T-stubs was close to 0.88. Furthermore, the load-carrying capacity of THOB bolted T-stubs was evaluated using existing specifications for comparison with the experimental and numerical results, and Eurocode 3 calculations for the plastic load-carrying capacities of THOB bolted T-stubs demonstrated a commendable level of precision. Finally design recommendations were put forward based on the test and finite element analysis results.

Electrothermally actuated network metamaterials with reconfigurable bending deformation modes

Reconfigurable metamaterials with specific deformation modes show great promise in applications such as multifunctional antenna, stretchable electronic device, and reconfigurable soft robot, due to their ability to achieve multiple operational states within a single system. Previous researches on active metamaterials with bending deformation responses revealed two main issues: (1) achieving reconfigurable deformation within the same metamaterial is challenging due to the reliance on uniform external field actuation; and (2) there is a lack of in-depth studies on the microstructure-property relationships for the bending deformation responses of network metamaterials due to the lack of theoretical analysis. To address these issues, this study presents a mechanical design strategy for an electrothermally actuated network metamaterials to realize reconfigurable bending deformation. A theoretical model describing the electrothermally actuated bending deformation responses is developed through a three-level analysis, which offers a comprehensive understanding of the parameter-property relationships and accurately describes the bending deformation behaviors. The validity of these mechanical models is confirmed through finite element analyses (FEAs) and experimental results. These mechanical models provide analytical solutions for crucial mechanical quantities, including the electrothermally actuated bending angles and effective strains for bending deformation responses. The bending behaviors of the reconfigurable metamaterials under electrothermal actuation can be adjusted by the key nondimensional geometric parameters and the actuation strategies. Additionally, experimental results and FE calculations demonstrate that multiple bending responses can be realized within a single metamaterial by different actuation strategies. This study offers comprehensive guideline from theoretical predictions, FE calculations, and experimental demonstrations for future researched of reconfigurable metamaterials to realize required deformation behaviors.

Dynamic responses of monopile offshore wind turbines under different wind-wave misalignment angles

Wind-wave misalignment is a common occurrence for monopile offshore wind turbines during extreme typhoon conditions. This phenomenon has a significant impact on the structural dynamic response of turbine structures and poses a threat to their structural integrity. In this study, finite element analysis is conducted on 75 sets of working conditions of monopile offshore wind turbines to investigate their dynamic response under different wind turbine operating states, wind-wave misalignment angles, and randomness of wind and wave load conditions. The results of the analysis indicate that the impact of wind-wave misalignment angles on the dynamic response of the monopile offshore wind turbine varies depending on the operational conditions. Furthermore, the study reveals that there are variations in the dynamic response of the monopile offshore wind turbine under different combinations of wind and wave loads. During the parked state and yaw system fault of the monopile offshore wind turbine, the most adverse working conditions need to consider wind-wave misalignment angles of 0° and 180°. In contrast, the most adverse working conditions for operational states emerge when the wind-wave misalignment angle is 90°. These findings highlight the importance of considering wind-wave misalignment angles and the randomness of wind and wave load conditions when assessing the dynamic response and structural integrity of monopile offshore wind turbines.

How dispersed LLZTO enhances ionic conductivity in LiFePO4 composite cathodes for solid-state batteries

To improve the ionic conductivity of the LiFePO4 cathode for high-performance solid-state lithium-ion batteries, we incorporated the chemically stable and ion-conductive Li6.75La3Zr1.75Ta0.25O12 (LLZTO) into the cathode. We discovered that the impact of this incorporation on enhancing conductivity was influenced by how well the LLZTO particles were dispersed. A solid-state battery constructed with the LiFePO4 cathode without any LLZTO incorporated exhibited an initial capacity of 146 mAh g−1 at 0.2C, with a retention of 26 % after 100 cycles of charge-discharge. When the cathode was incorporated with LLZTO particles in their original agglomerated state, the initial capacity remained similar to the pristine one, but the retention decreased to <20 %. However, when LLZTO was well-dispersed during incorporation, the initial capacity increased to 160 mAh g−1, and retention improved to over 95 %. The difference in the effectiveness of incorporating dispersed and agglomerated LLZTO on the electrochemical performance has been clarified to be mainly related to the polarization of Li+ during transport in the cathodes. This was elucidated by numerical simulations based on finite element analysis, which revealed that incorporating LLZTO agglomerates leads to a deficiency of Li+ transport in specific regions within the LiFePO4 cathode and non-uniform Li+ transport through LLZTO, resulting in reduced overall cathode conductivity and battery performance.

CoFe2O4-BaTiO3 Core-Shell-Embedded Flexible Polymer Composite as an Efficient Magnetoelectric Energy Harvester

Flexible magnetoelectric (ME) generators gained immense interest due to the broad applications in wearable and Internet of Things (IoT)-based devices. The key to achieving high energy conversion performance of 0-3 type ME composite films is the prevention of filler aggregation in the polymer matrix and accessing the full potential of intrinsic properties of filler. To achieve high performance, a flexible ME composite film was fabricated by homogeneous distribution of magnetostrictive CoFe2O4-BaTiO3 core-shell (CBCS) fillers into piezoelectric polyvinylidene fluoride (PVDF) polymer. The ME composite film generates an enhanced energy conversion efficiency by optimizing the shell thickness of CBCS and maximizing the electroactive β-phase at the BaTiO3 shell-PVDF interfacial region. The observed ME coefficient of the film reached up to 710 mV/cm∙Oe. Multiphysics simulations based on the finite element analysis were adopted to investigate the role of BaTiO3 shell thickness on the performance of ME film. This study paves the way to achieve higher filler loading content in the ME composite films to develop an efficient, flexible ME generator for eco-friendly permanent power sources.

Analyzing the Influence of Welding Process Selection on Residual Stresses in Tube-to-Tubesheet Welded Joints

Tube-to-tubesheet joints are used in the fabrication of shell and tube type heat exchangers, steam generators, boilers, condensers, and end shields of pressure tube type nuclear reactors like CANDU (Canada Deuterium Uranium) and PHWR (Pressurized Heavy Water Reactor). The weld joints connecting the tubes to the tubesheets are of prime importance as they have a direct impact on equipment safety. In the fabrication of these critical class-1 nuclear components, full penetration weld joints are used. Typically, these full penetration weld joints are created through multi-pass Tungsten Inert Gas (TIG) welding. However, more recent techniques, such as single-pass Electron Beam Welding (EBW) and Laser Beam Welding (LBW), have also been employed for this purpose. The fabrication time of these pieces of equipment containing full penetration weld joints can be drastically reduced if single-pass welding techniques are used compared to multi-pass welding techniques. However, the residual stresses developed in these joints due to the localized heat input and the substantial constraints of the tubesheet are unknown. Different welding processes, such as TIG welding, EBW, or LBW, can lead to varying levels of residual stresses in these joints, subsequently impacting their longevity. Weld residual stress plays a significant role in the initiation of failure modes of these tube-to-tubesheet welded joints, such as stress corrosion cracking, fatigue, and corrosion fatigue.This paper analyzes the residual stresses developed at the tube-to-tubesheet interface resulting from different welding techniques, such as multi-pass TIG welding and single-pass EBW/LBW. A comprehensive three-dimensional coupled thermo-mechanical finite element analysis is employed for this purpose. The findings reveal a significant difference, with single-pass EBW exhibiting up to 32% lower residual stresses compared to multi-pass TIG welding. Additionally, the Heat Affected Zone (HAZ) in EBW is approximately 50% smaller than in TIG welding, and the equivalent distortion in EBW is reduced by 90% compared to multi-pass TIG welding. In summary, this investigation concludes that single-pass EBW offers distinct advantages for tube-to-tubesheet weld joints, including reduced residual stresses, a smaller HAZ, and lower distortions.

Static and Thermal Analysis of Internal Combustion Engine Valves

Abstract: In this paper the 3D model of the internal combustion engine valves was realized using Autodesk Inventor Professional 2024 and finite element analysis, static and thermal was performed, in order to determine the state of stress, deformation and temperature evolution, by applying restrictions and loads conditions. Two materials were chosen, for internal combustion engine valves, in accordance with the specialized literature. The materials taken for static and thermal analysis was Stainless Steel AISI 446 and NiCr0TiAl. Following the comparative study for the two models, it can be specified the importance of the material for the construction of the internal combustion engine valves who depends on the material properties and their design.

Analysis of Wind Response of Braced and Unbraced Tall Building

As high-rise buildings become increasingly prevalent worldwide, their complex structural components and the need for high stability pose challenges for safety and design requirements. The present study investigates the influence of bracing systems and plan aspect ratios on the ability of tall buildings to withstand wind loads. The study aims to analyze the effects of these variables on the wind-induced responses of tall buildings and improve bracing system design for structures with high aspect ratios. Numerical simulations using finite element analysis software are conducted, creating various building models with different aspect ratios and bracing systems. The displacement, drift, base shear responses and time period of each model are examined to evaluate the effectiveness of different bracing systems. The results highlight the significant impact of aspect ratio on the response to wind loads, with larger aspect ratios experiencing greater motion and stress. However, well-designed bracing systems prove effective in reducing wind-induced motion and stress. The study provides insights on best bracing system for different aspect ratios, offering valuable insights for creating safer and more resilient high-rise buildings.

Parametric Study on Structural Performance According to the Condition Grade of Open-cut Electric Power Tunnel

In this study, the structural performance of electric power tunnels was evaluated based on the type and degree of damage. For experimental performance evaluation, a power structure test specimen was designed with a state safety performance of grade D corresponding to a concrete damage area ratio of 44% and structural safety performance of grade D with a reduced cross-section of 25% of the main reinforcement of the upper slab. The electric power structures with grade D state safety performance and structural safety performance exhibited 63% load-bearing capacity compared to those without damage. Cracks occurred on the outside of the structure under the experimental conditions simulating the overburden load, implying the possibility of corrosion of the outer reinforcing bars of the real structure. Finite element analysis showed that reducing the area of the outer main rebar of the upper slab caused more significant reduction in the load-bearing capacity than that of the inner main rebar.

Enhancing solar energy systems: The role of computational and automation techniques in achieving net zero by 2050

This review aims to show how computational and automation can be applied to optimize the solar power system toward net-zero emissions in 2050. It emphasizes the power of data analytics, machine learning and automated systems for optimizing business models and measuring the performance of solar technology. The role of solar power in decarbonizing our energy needs and lowering carbon emissions is discussed along the global climate agenda. It also discusses novel uses such as self-teaching robots for solar panel inspection and automated manufacturing to increase the efficiency and sustainability of solar power generation. Additionally, it addresses the need for sophisticated research tools such as computational fluid dynamics (CFD) and finite element analysis (FEA) to create new technologies in the solar market and ultimately meet the ambitious renewable energy targets of 2050.

Case study of bearing capacity failure in a 4-story reinforced concrete building

This case history analyzes the bearing capacity failure of a 4-story reinforced concrete building in Benghazi, Libya, constructed in Fall 2000. The building has a plan area of 65 m² and is supported by an 80 cm thick raft foundation resting on collapsible sandy loess, which can lose shear strength when wet. Several months before the building's failure, nearby construction work caused a broken pipeline, leading to significant water leakage. This moisture infiltrated the soil under the foundation, reducing its bearing capacity, particularly on the northern side. In winter 2002, the building began to tilt northward due to this reduced capacity, although inspections revealed no structural cracks, attributed to the rigidity of the raft foundation and reinforced concrete shear walls. The paper discusses the geotechnical properties of the supporting soil and uses finite element analysis to show that the bearing pressures exceeded allowable limits under wet conditions, emphasizing the importance of moisture content in assessing soil stability. This case highlights the complexities of foundation design and the critical impact of environmental factors on soil behavior, advocating for thorough geotechnical assessments and ongoing monitoring of conditions around structural foundations.

Characterization of Three-Mode Combination Internal Resonances in Electrostatically Actuated Flexible–Flexible Microbeams

Abstract Nonlinear intermodal coupling based on internal resonances in MEMS resonators has advanced significantly over the past two decades for various real-world applications. In this study, we demonstrate the existence of various three-mode combination internal resonances between the first five flexural modes of electrostatically actuated flexible–flexible beams and dynamic modal interaction between three modes via internal resonance. We first calculate the natural frequencies of the beam as a function of the stiffnesses of the transverse and rotational springs of the flexible supports, utilizing both analytical formulation and finite element analysis (FEA). Following this, we identify six combination internal resonances among the first five modes and use applied DC voltage to validate the exactness of one commensurable internal resonance condition (ω2=ω5−ω4). Subsequently, we studied a detailed forced vibration analysis corresponding to this resonance condition by solving the five-mode coupled governing equations through numerical time integration and the method of multiple scales. The results compellingly exhibit three-mode intermodal coupling among the second, fourth, and fifth modes as a function of excitation amplitude and frequency. Alongside this, intriguing nonlinear phenomena such as threshold behavior, saturation phenomena, and autoparametric instability are observed. Finally, this paper provides a systematic methodology for investigating three-mode combination internal resonances and related nonlinear dynamics, offering significant insights that could be used in observing phonon or mechanical lasing phenomena in MEMS resonators.

Finite Element Analysis and Design Optimisation of Welding robot base using ANSYS

The study on Finite Element Analysis and Design Optimization of a welding robot base using ANSYS explores the crucial role of welding robots in enhancing industrial productivity and quality. It addresses the challenges of structural integrity, operational efficiency, and durability under harsh conditions. The research focuses on optimizing the robot base design to withstand high production demands, using ANSYS for detailed modelling and simulation. It reviews previous studies highlighting the importance of vibrational characteristics and structural dynamics in robot design. The methodology involves creating a geometric model, defining material properties, meshing, and applying boundary conditions and loading scenarios. The results indicate that the optimized design significantly improves stress distribution, reduces deformation, and enhances the dynamic response, making the robot base more robust and reliable. The study concludes with recommendations for broader applications in robotic systems to improve safety and productivity in industrial settings.

Study on Winding Inductances in Stator Surface-Mounted Permanent Magnet Machines

Winding inductance always plays a key role in the electromagnetic performances of stator surface-mounted permanent magnet (SSPM) machines, including their flux-weakening capability, prospective fault current, power factor, current ripple, etc. Generally speaking, winding inductance mainly comprises three components: an air-gap component, a slot-leakage component, and an end-leakage component. In this paper, firstly, the winding pole pairs of SSPM machines are investigated based on the magneto-motive force-permeance model, through which the winding configurations can also be determined. Then, according to the winding configurations, three analytical expressions for each inductance component are derived to evaluate the winding inductance per phase. In addition, finite element analysis (FEA) is employed to verify the effectiveness of the derived analytical expressions. Meanwhile, three prototyped SSPM machines are manufactured, and their winding inductances are measured to further verify the analytical expressions. The measured results agree with both the analytical and FEA results very well.

On the Relative Effects of Wall and Intraluminal Thrombus Constitutive Material Properties in Abdominal Aortic Aneurysm Wall Stress.

An abdominal aortic aneurysm (AAA) is a dilation localized in the infrarenal segment of the abdominal aorta that can expand continuously and rupture if left untreated. Computational methods such as finite element analysis (FEA) are widely used with in silico models to calculate biomechanical predictors of rupture risk while choosing constitutive material properties for the AAA wall and intraluminal thrombus (ILT). In the present work, we investigated the effect of different constitutive material properties for the wall and ILT on 21 idealized and 10 unruptured patient-specific AAA geometries. Three material properties were used to characterize the wall and two for the ILT, leading to six material model combinations for each AAA geometry subject to appropriate boundary conditions. The results of the FEA simulations indicate significant differences in the average peak wall stress (PWS), 99th percentile wall stress (99th WS), and spatially averaged wall stress (SAWS) for all AAA geometries subject to the choice of a material model combination. Specifically, using a material model combination with a compliant ILT yielded statistically higher wall stresses compared to using a stiff ILT, irrespective of the constitutive equation used to model the AAA wall. This work provides quantitative insight into the variability of the wall stress distributions ensuing from AAA FEA modeling due to its strong dependency on population-averaged soft tissue material characterizations. This dependency leads to uncertainty about the true biomechanical state of stress of an individual AAA and the subsequent assessment of its rupture risk.

Characterization of thin-walled self-healing microcapsules reinforced with multi-walled carbon nanotubes

This study presents a novel approach to fabricating thinner shells and significantly enhancing the fracture strength of melamine-urea-formaldehyde (M-U-F) microcapsules reinforced with multi-walled carbon nanotubes (MWCNTs). Unlike previous studies that primarily focused on single-walled carbon nanotubes (SWCNTs) or MWCNTs in polyurea-formaldehyde (PUF) shells, this research advances microcapsule technology by exploring MWCNT reinforcement in M-U-F shells. We employed a dual experimental-numerical approach, combining the precision of micro-compression tests with the predictive capabilities of finite element analysis (FEA) to determine the elastic modulus of MWCNT-reinforced M-U-F microcapsules. This method offers new insights into the mechanical behavior of these microcapsules. Our findings indicate an 8.8% increase in fracture load and a 14.6% reduction in fracture displacement for MWCNT-reinforced microcapsules compared to conventional M-U-F microcapsules. Additionally, FEA confirmed the results of the micro-compression tests, showing that MWCNT-reinforced microcapsules had the best correlation with an elastic modulus of 4.00 GPa. Conventional M-U-F microcapsules corresponded to an elastic modulus of 2.25 GPa. These results provide a comprehensive understanding of how nano-reinforcement influences the structural properties of thin-walled microcapsules, with potential applications in composite damage repair and beyond.

Evaluating the Efficacy of Lead-Free Piezoelectric Materials in Microcantilever Based Vibration Energy Harvesters

Abstract The piezoelectric materials have been extensively utilized in various applications, such as sensors, actuators, and energy harvesters. This study evaluates the performance of six lead-free piezoelectric materials- aluminium nitride (AlN), barium titanate (BaTiO3), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), polyvinylidene fluoride (PVDF), and zinc oxide (ZnO) in MEMS-based piezoelectric vibration energy harvesters (PVEHs) using cantilever configurations. Finite element analysis via COMSOL Multiphysics was employed to assess the deflection, voltage, and power outputs of these materials at their resonance frequencies, both with and without proof masses. The results indicate that BaTiO3 and PVDF cantilevers exhibited the highest voltage outputs, reaching 207.14 mV and 202.07 mV, respectively, with AlN also showing comparable performance at 184.72 mV. ZnO-based cantilevers demonstrated the highest power output of 1.35 nW without proof masses and 190.5 nW with proof masses, indicating its potential for high-power applications. The addition of proof masses generally reduced resonant frequencies but enhanced power outputs, like for ZnO. This comprehensive analysis underscores the critical impact of material selection and structural modifications on the efficiency of PVEHs, with BaTiO3, PVDF, and ZnO emerging as the most promising candidates for optimizing energy harvesting devices. This research lays a foundation for further advancements in piezoelectric MEMS technology, aiming for more efficient energy harvesting solutions.&amp;#xD;