Finite Element Analysis Techniques Research Articles

Optimising surgical efficiency by designing lightweight skull-PSI assemblies and curved fixture plates for cranial reconstruction using FEA

Cranial reconstruction using implants is critical for protecting intracranial structures and restoring cerebral hemodynamics in cases of cranial defects caused by accidents, diseases or cancer. Patient-specific implants (PSIs) made from materials such as polyether-ether-ketone (PEEK), are required to be lightweight, high in strength and capable of mimicking the natural bone structure. Effective fastening mechanisms using the required number of fixture plates are essential for seamless integration between the PSI and the cavity of a defected skull for successful cranial reconstruction. This study explores the optimal number and shape of fixture plates required to join a Skull-PSI assembly, such that the overall weight of the PSI remains minimal, and to ensure that these assemblies do not fail when subjected to heavy external loads of 950 N. PEEK material was used for PSI, natural bone for the defected skull and Titanium Alloy (Ti-6Al-4 V) for the fixture plates. Conventional straight shaped fixture plates often require manual bending for correct fitment on the Skull-PSI curved surface, which increases a surgeon's time and effort. Curved shaped fixture plates were designed, to save on this time and effort and enhance the contact surface area with the Skull-PSI surface. Four, three and two numbered, straight and curved shaped fixture plates were investigated using Finite Element Analysis (FEA) techniques. Three numbered, curved shaped fixture plates were found to be optimal, to generate a 7-gram lightweight PSI that could successfully sustain external loads up-to 950 N without failure. Ultimately, these design improvements would benefit both patient and surgeon in aspects of surgery time and patient comfort.

Reliability Assessment of the Casted Steel Function Block in Gasoline Fuel Rails

In this study, the reliability of the casted function block, a critical component of the fuel rail assembly (FRA), is examined under the pressure and thermal loads typically encountered in an engine compartment. The function block serves a dual purpose: it acts as a holder for the fuel rail, securing it to the cylinder head (CH), and it includes the injector cup, which connects the injectors to the rail. This component is manufactured as a single piece using casting methods. To assess the stress experienced by the function block, Finite Element Analysis (FEA) techniques are employed. Additionally, a specialized mechanical pulse test is developed to determine the fatigue limits of the casted function block. This testing is crucial for understanding how the component will perform under cyclic loading conditions. The failure probability of the function block is quantified by generating S-N (stress-cycle) curves based on the results from the mechanical pulse tests. These curves illustrate the relationship between the applied stress and the number of cycles to failure, allowing for a comprehensive analysis of the component's durability. Ultimately, the study demonstrates that the failure probability of the casted function block is estimated to be less than 1 ppm (parts per million) for serial production. This finding confirms that the function block meets the stringent reliability requirements necessary for automotive applications, ensuring its performance and safety in the demanding environment of an engine compartment.

Design and Analysis of Composite Materials for High-Pressure Environments

Composite materials have proved to be a critical application in high pressure application fields owing to their mechanical characteristics, light weight and flexibility. The current work is aimed at the design and investigation of sophisticated composite materials for high pressure applications and to overcome the drawbacks of metals and alloys. The study also discusses fibers such as carbon fibers or glass fibers, and matrices, with the focus on the best lay-up configurations and size-dependent anisotropic behavior. Several techniques like mechanical testing techniques, and finite element analysis techniques to estimate the mechanical properties like tensile strength, fatigue life and failure modes etc.. The study again stresses the comparative advantage of hybrid composite materials when it comes to stress strength, damage invulnerability, and stability. Suggestions for further studies include the investigation of bio based composites and optimization of the fabrication methodology for sustainability aspect. These outcomes prove useful for aerospace, marine and energy industries firms where high pressure resilience is paramount.

Dynamic Response Analysis of Orthogonal and Skewed Slabs to Touch-off Explosion: Investigating Comparative Efficacy and Damage Mechanisms

Abstract Skewed slabs, deviating from conventional orthogonal alignment, pose distinctive structural hurdles. Despite their aesthetic allure and spatial efficiency, their incorporation entails intricate challenges in design, analysis, and construction. Within structural frameworks, slabs are pivotal elements susceptible to devastating impacts from contact explosions, like those triggered by suitcase or parcel bombs, in numerous engineering scenarios. The events like the Beirut explosion in 2022 and the Tianjin blast in 2023 serve as poignant reminders of the urgent need to grasp and address these dangers effectively. Slabs, whether arranged orthogonally or skewed, are fundamental in various engineering frameworks. Despite their key role in load support, slabs are highly vulnerable to damage from explosions, particularly contact blasts like suitcase bombs. Understanding slab behavior under such conditions is crucial for bolstering structural resilience and devising effective defense strategies against potential threats. This research endeavors to contribute to defense technology by examining the dynamic response of both orthogonal and skewed slabs to contact explosions, furnishing indispensable insights aimed at fortifying structural security in diverse environments. The blast is emulated through the utilization of the Eulerian-Lagrangian method, employing the Finite Element Analysis (FEA) technique with the aid of the Abaqus software. Slabs featuring various degrees of skew, including 15°, 30°, and 45°, are under scrutiny, and their comparative efficacy is evaluated against the benchmark of an orthogonal slab. The performance of the orthogonal slab is validated by comparing it to data from previous experiments published in academic literature. The findings revealed that with an escalating skew angle, there’s a reduction in perforation dimensions alongside a rise in peripheral damage. Furthermore, the hierarchical order of damage severity among configurations corresponds to the angles: 15° > 30° > 45°, highlighting critical considerations for structural resilience.

Influence of mechanical characteristics of materials of threaded connections of oil and gas downhole equipment on their fatigue life

Abstract Threaded connections of downhole oil and gas equipment such as tool joints of drill pipes and sucker rod connections operate under difficult conditions of significant cyclic loading and a corrosive environment. This often leads to material fatigue and parts failure. Therefore, the design of such threaded connections requires accurate methods for calculating fatigue life. Using an improved finite element analysis technique in Abaqus/CAE and fe-safe, which takes into account maximum plastic deformation in the first steps of the simulation, the influence of the mechanical characteristics of the materials of these threaded connections on their fatigue life was investigated. An increase in the ductility of the pin or box material leads to equalization of loads along the thread and an increase in the fatigue safety factor, but only if the fatigue strength of this material is sufficient. An additional increase in fatigue life can be achieved by optimal plastic pre-deformation of the connection under a high axial external load. The results prove that the fatigue life of these threaded connections can be significantly improved without optimizing their geometric parameters.

The influence of anchored CFRP on the torsional and bending behavior of sulfate damaged RC beams

Reinforced Concrete (RC) structural elements are subjected to continuous capacity deterioration due to different overloading situations or environmental conditions, such as sulfate attack, steel corrosion, and alkali-activated binders. Therefore, ensuring the system's integrity is a challenging issue faced by municipal and governmental agencies. This raises the need to upgrade the structural capacity by the utilization of strengthening materials of different material types, such as the externally bonded Carbon Fiber Reinforced Polymer (CFRP) that proves efficiency in increasing the flexural and shear capacities of the strengthened system along with maintaining their ductile type of failure. In contrast, a major deficiency exists in the externally bonded technique, the debonding failure, limiting the benefits from the FRP material's high tensile strength and could be solved using a proper and efficient anchoring method. A new and novel use for the CFRP anchored strengthening system was proposed in this study to upgrade the beam's capacity against the effect of sulfate attack damage. The behavior of simply supported strengthened beams was examined in this study under the effect of combined torsional and bending stresses using the Nonlinear Finite Element Analysis (NLFEA) technique using twenty-two models that are divided into six main groups. The investigated parameters were the depth of the anchored CFRP (wfa) (0.00 hf, 0.25 hf, 0.50 hf, 0.75 hf, and 1.00 hf) and sulfate damage cycles (0 (without), 60, 90, and 150 cycles). The structural efficiency of the modeled beams was examined using the torsion-twist curves, the torsion and twist capacities at the ultimate stage, failure mode, stiffness (pre and post-cracking), steel, stirrups, and CFRP strains, and finally, the energy absorption. It has been found that the resulting improvement percentage has a directly proportional relationship with the depth of the anchored CFRP. In contrast, an inversely proportional relationship exists between the improvement percentage and the number of exposed sulfate damage cycles. In conclusion, applying externally boned anchored CFRP has a superior contribution to the RC beams structural performance.

Effect of dental implant neck profile switching on crestal bone healing

Introduction: The majority of dental implants and prostheses rely on the association with the soft tissues that may be vulnerable to future requirements. There are two main requirements for osseointegration: first, the bone must be healthy; second, the implant must be stable and able to withstand the functional load. Methods and Results: Using both the computer12 model and finite element analysis technique to assess the bone space volume in implants with narrow-neck hybrid design compared with butt platform and bevel design at an inter-implant distance of 1 mm, the result showed approximately 56.7 mm in the butt joint platform design implant and between two bevel platforms (+2.74% or more), while it showed 78.42 mm (+38.32%) between two narrow-neck hybrid designs. Discussion and Conclusion: The implant platform switching technique is used to decrease the stress on the crestal bone and allow for better load distribution. This can be done at two levels: one is at the fixture–abutment interface, and the second within the bone at the fixture itself in the body–neck area. The narrow-neck hybrid design seems to be superior in lowering the stress on crestal bone and to provide more room for bone healing potential with less negative effect on soft tissue healing.

Study on the Influence of Wind Load on the Safety of Magnetic Adsorption Wall-Climbing Inspection Robot for Gantry Crane

The maintenance of the surface of steel structures is crucial for ensuring the quality of shipbuilding cranes. Various types of wall-climbing robots have been proposed for inspecting diverse structures, including ships and offshore installations. Given that these robots often operate in outdoor environments, their performance is significantly influenced by wind conditions. Consequently, understanding the impact of wind loads on these robots is essential for developing structurally sound designs. In this study, SolidWorks software was utilized to model both the wall-climbing robot and crane, while numerical simulations were conducted to investigate the aerodynamic performance of the magnetic wall-climbing inspection robot under wind load. Subsequently, a MATLAB program was developed to simulate both the time history and spectrum of wind speed affecting the wall-climbing inspection robot. The resulting wind speed time-history curve was analyzed using a time-history analysis method to simulate wind pressure effects. Finally, modal analysis was performed to determine the natural frequency and vibration modes of the frame in order to ensure dynamic stability for the robot. The analysis revealed that wind pressure predominantly concentrates on the front section of the vehicle body, with significant eddy currents observed on its windward side, leeward side, and top surface. Following optimization efforts on the robot’s structure resulted in a reduction in vortex formation; consequently, compared to pre-optimization conditions during pulsating wind simulations, there was a 99.19% decrease in induced vibration displacement within the optimized inspection robot body. Modal analysis indicated substantial differences between the first six non-rigid natural frequencies of this vehicle body and those associated with its servo motor frequencies—indicating no risk of resonance occurring. This study employs finite element analysis techniques to assess stability under varying wind loads while verifying structural safety for this wall-climbing inspection robot.

Deep adversarial learning models for distribution patterns of piezoelectric plate energy harvesting

This paper presents a novel approach utilizing piezoelectric plate structures with random electrode distribution patterns for energy harvesting applications across various vibration modes. For the first time, leveraging electromechanical Finite Element Analysis (eFEA) and data extraction techniques, we investigate the integration of conditional Generative Adversarial Networks (cGAN)-based dynamic models. The cGAN offers an effective technique for generating realistic synthetic data conditioned on input parameters, thereby enabling the creation of diverse and representative datasets for training energy harvesting systems. The integration of eFEA with cGAN opens up new possibilities for optimizing the design and performance of piezoelectric energy harvesters across various applications. Specifically, we explore four distinct cGAN models-based mechanics of energy harvesters by deploying distribution patterns. These models include training data generated by stacking simultaneously mode images, utilizing separate cGAN models for each mode, labeling images by mode, and concatenating all mode images into one. Our study focuses on assessing the effectiveness of these models in minimizing loss in cGAN-based power generation and predicting Structural Similarity Index Measure (SSIM) values, and more importantly, identifying the predicted data point outputs from the generated pixel image extractions. By analyzing the generated data from numerical model and its application in deep learning, we aim to enhance the understanding of the effects of distribution patterns and image processing techniques for optimal power generation and the effectiveness of piezoelectric energy harvesting systems across different vibration modes. The studies explore how different distribution patterns affect the power harvesting efficiency and frequency bandwidth, utilizing the generated datasets.

Stress–strain curve estimation from load–depth curve of spherical indentation test based on finite element analysis and optimization

A stress–strain curve is one of the most important indicators of material properties for characterizing constitutive behavior. It can be directly obtained from a conventional uniaxial tensile test or load–displacement curve using an instrumented indentation test (IIT). An IIT uses formulations of the effective indentation strain and stress or the iterative finite element analysis (FEA) of the indentation process using a constitutive model, such as a power-law constitutive model. In this study, an iterative FEA is used to obtain the engineering stress–strain curve. However, it focused on considering the realistic plastic flow of specific materials without idealizing the power-law constitutive model. A concept for stress–strain estimation using a master stress–strain curve for specific materials was proposed, and its usefulness was validated via FEA and optimization techniques. In the future, this methodology can be extended to deep learning technology to address the issue of time consumption in iterative optimization methods.

Aircraft joint structure lightweight design

PurposeThe purpose of this article is to carry out a lightweight design of the joint structure according to the service condition of the joint.Design/methodology/approachThe finite element analysis techniques are used along with the variable density structure topology optimization method, the multi-island genetic algorithm for structural dimension optimization and the fatigue life analysis method.FindingsUtilizing the topology optimization method and size optimization method, the mass of the optimized model for the A100 material model is 9.67 kg. Compared to the pre-optimized model, the mass decreases by 8.23 kg, representing a weight reduction of 46.0% in the optimized model; the fatigue life of the aircraft joint is predicted to be a maximum of 1,460,017 cycles.Originality/valueThe originality of this study is that it provides new design ideas for the lightweight design of aircraft load-bearing structures.

Reliable simulation analysis for high-temperature inrush water hazard based on the digital twin model of tunnel geological environment

In complex mountainous terrains, tunnel construction faces unique challenges from high-temperature water inrush hazards, a systemic risk arising from the interplay of stress, seepage, and temperature fields. Traditional simulation methods, focusing on isolated disaster scenarios, fall short in addressing the multifaceted nature of these risks due to geological ambiguity and data incompleteness. Digital twin technology presents an effective solution to these challenges; however, its core challenge lies in how to utilize digital twin technology for data-model-co-driven simulation analysis of coupled multi-physical fields in situations of incomplete data. This paper introduces a digital twin paradigm for the simulation analysis of water inrush, which significantly enhances efficiency and accuracy through the integration of advanced machine learning and finite element analysis techniques. Specifically, this is achieved by combining a high-precision geological modeling method based on Gaussian Processes (GP) with a parameter calibration method through Gaussian Process-Differential Evolution (GP-DE) back-analysis. Firstly, a voxel structure is utilized to integrate the multi-field attribute features of the tunnel environment. Secondly, through the integration of multi-source advanced geological prediction data, we construct a dynamic digital twin model of the tunnel environment leveraging machine learning techniques. To overcome the issue of low modeling accuracy, the GP is employed, enhancing the exploitation of latent information within multi-source geophysical data. Lastly, we utilize the GP-DE back-analysis method to calibrate the parameters of the tunnel environment, thereby enhancing the precision and reliability of water inrush simulations. The method has been validated through application to a section of an ultra-high-temperature water inrush tunnel in China, featuring a burial depth of 230 meters. The accuracy of the method is corroborated by the monitoring data from the tunnel, supporting dynamic optimization design and safety prevention measures during construction.

Design and Optimization of Steel Structures for Solar Panel Systems

Abstract: Structural components are fundamental for supporting mechanical machines in industrial settings. These structures are designed not only to bear the weight of the machines but also to withstand the vibrations generated during operation. The project at hand focuses on integrating basic structural sections to create a complete mechanical framework. Our goal is to collaborate with an industry specializing in support structures for various electrical units. From our initial analysis, we observed that many of these industries rely on conventional manufacturing practices and past experience to design structures, often leading to overdesign. No finite element analysis (FEA) or theoretical calculations are typically applied. We propose introducing modern FEA techniques and concepts to optimize and refine these designs for improved efficiency.

Exploring FEA Techniques for Bending Rectangular Glass Plates into Parabolic Shapes

Abstract: A structural Finite Element Analysis (FEA) was conducted, incorporating both linear and nonlinear analysis. The investigation considered geometric nonlinearity, material nonlinearity, and boundary nonlinearity, also known as contact analysis. All boundary conditions, loadings, and material properties used in the analysis were based on real-world conditions. Experimental validations were performed to confirm the accuracy of the FEA results, providing strong confidence in the investigation's findings.

Seismic resilience assessment of sheet-pile wharves in liquefiable soils using different liquefaction countermeasures

Seismic resilience assessment is essential for maintaining the functionality of sheet-pile wharves in liquefiable soils, preventing significant damages and minimizing losses during earthquakes. This study delves into the seismic resilience of sheet-pile wharves, focusing specifically on the effectiveness of four different liquefaction countermeasure techniques: anchor lengths, cement deep mixing, stone columns, and soil compaction. As such, an advanced two-dimensional (2D) Finite Element (FE) computational framework is established, motivated by a typical large-scale sheet-pile wharf configuration. Within this framework, a recently developed multi-yield surfaces plasticity model is employed, with the modeling parameters calibrated through undrained stress-controlled cyclic triaxial tests and a centrifuge test. Subsequently, the impacts of these liquefaction countermeasures on the seismic resilience of the sheet-pile wharves are systematically investigated. Additionally, the effectiveness of combining longer anchor lengths with the other three mitigation techniques to enhance the seismic resilience of the sheet-pile wharves are examined. It is demonstrated that the synergistic effects of different liquefaction countermeasures can further reduce the liquefaction potential, thereby improving the seismic resilience. Overall, the FE analysis technique and the resulting insights are highly significant for the seismic resilience assessment of equivalent sheet-pile wharves in liquefiable soils, particularly when implementing such liquefaction mitigation countermeasures.

Polymer gear failure prediction: A regression-Based approach using FEA and photoelasticity technique

The research aims to develop a model to predict the maximum contact stress depth, which will be correlated with polymer gear failures such as wear and rapid thermal deformation. A thorough 3D Finite Element Analysis (FEA) was performed for different gear parameters (varying module, number of teeth, and face width) in different combinations (Polymer – Polymer, Steel – Polymer, and Polymer – Steel). The simulation results showed that the contact stress depth increases with respect to the module and number of teeth; meanwhile, very negligible variations were found along the face width. Also, the findings indicate that the contact stress depth varied in the following descending combinations of gear pair: Polymer – Polymer, Steel – Polymer, and Polymer – Steel. The 3D FEA contact stress patterns were validated experimentally by utilizing the in-house developed photoelasticity test rig. The data obtained from the simulation results were used to develop regression models (Linear regression and Random Forest regressor) for estimating the maximum contact stress depth. A feature importance study was done using the mean reduction of the Gini index or impurities in random forest. It was found that torque applied and contact width of the gear pair were significantly influenced by the contact stress depth. Finally, an equation was developed correlating torque and contact width to predict the depth occurrence of maximum contact stress through which the failure mode of the polymer gear could be predicted.

FEA-based pole arc optimization and sensitivity analysis of 8/6 SRM for EV application

The optimization of the pole arcs and sensitivity analysis of a 4-phase 8/6 Switched Reluctance Motor (SRM) using the Finite Element Analysis (FEA) technique for the Electric Vehicle (EV) application is presented in this article. The motor's power rating is estimated from the tractive force of an e-rickshaw(3-wheeler). Optimizing the pole arc in SRMs is essential for obtaining an optimal balance of performance, efficiency, and operating smoothness. This makes it a vital part of SRM design. The motor performance is analyzed by fixing the stator pole arc while varying the rotor pole arc and vice versa. The main performance attributes like torque, torque ripple, torque per rotor volume, and efficiency of an 8/6 SRM with various pole arc values are examined using the transient FEA method. A sensitivity analysis is conducted to evaluate the range of variation in the performance parameters of the motor when the pole arcs vary. Various performance indices, such as torque, torque ripple (TR), efficiency, and Torque Per Volume (TPV), are considered for the analysis. The sensitivity analysis is carried out based on the transient analysis. Finally, based on the findings, the optimal combination of pole arcs is determined and analyzed the performance using the FEA method. An electromagnetic design tool called Infolytica MOTORSOLVE is used to construct the FEA models and extract the characteristics.

Optimized gap positions for improved leakage impedance in dry-type transformer design

The power and distribution transformers must be properly designed to operate in a variety of conditions and manufactured following all applicable international standards to provide a reliable energy supply to consumers. The transformer can fail if it is improperly designed, and it cannot withstand the short-circuit condition if the short-circuit current is not calculated properly. Short-circuit current can be easily calculated by evaluating the leakage impedance. Customers can also demand the transformer companies to increase or decrease the leakage impedance. This paper evaluates the effect of the gap's position in the four different sections of the high voltage winding on the leakage impedance of the two-winding transformer and proposes effective design options for minimizing the leakage impedance. The accuracy of the finite element models was also investigated using an experimental laboratory transformer model specially designed for optimizing the leakage impedance. The experimental and finite element methods results show that the leakage impedance can be changed to the desired value and limits and easily assessed by the finite element analysis technique. The results indicate that even with the same use of the winding and core material, there was a considerable difference in the leakage impedance for each of the conditions.

Optimal design of low frequency rubber vibration isolator

Abstract Low frequency vibration isolator is a common structure vibration control device, widely used in transportation and machinery manufacturing fields. This paper is centered around enhancing the optimization design of rubber isolators operating at low frequencies. In the initial section, the paper introduces the structural framework and operational principles of rubber isolators. Furthermore, it delves into the analysis of their significance and potential applications within engineering contexts. Subsequently, the paper narrows its focus to address the design challenges concerning rubber isolators with low-frequency capabilities. A comprehensive three-dimensional model is constructed using ANSYS software, employing finite element analysis techniques. The paper employs a multi-objective optimization algorithm through a direct optimization module to facilitate the optimization design process. Within this study, the NSGA-II algorithm was employed to drive the optimization of design, with the objective of achieving a 10 Hz frequency for a series of dual rubber isolators, while simultaneously constraining static deformation to within 8 mm. The outcomes of this investigation emphasize the successful attainment of optimization goals by meticulously fine-tuning the structural dimensions of the isolators.

Development of core support barrel installation tool for a bypass flow reduction in nuclear reactor core

Reactor internals are installed in the reactor vessel and are subsequently removed during periodic inspections. To facilitate this process, a gap is maintained between the outlet of the Core Support Barrel (CSB) and the hot-leg nozzle of the Reactor Vessel (RV). However, this gap causes considerable bypass flow, leading to wasted coolant and pump power. This paper presents an improved design of reactor internals to prevent bypass flow and introduces a tool for handling the internals. Advanced computational simulations were used to investigate the tool’s viability. The tool was designed using advanced Finite Element Analysis (FEA) techniques, and its operation was simulated and evaluated with ANSYS Rigid Body Dynamics. The results showed that the CSB can be installed using the insertion tool in a manner that ensures contact with the RV’s interior surface, thereby decreasing the gap and lessening the bypass flow, as well as increasing the structural stiffness of CSB under seismic loads.