Finite Element Analysis Model Research Articles

Research on DC switching based piezoelectric actuator

Piezoelectric actuators provide several advantages, including rapid response time, travel control, high resolution and actuation efficiency. They are a good candidate for actuating mechanical switches designed for electrical circuit breakers. This study investigates the utilisation of an Amplified Piezoelectric Actuator (APA) in Block-Free (B-F) operational mode as an actuation unit for a Fast-Mechanical Switch (FMS) and an Ultra-Fast Disconnector (UFD) to be utilised in a DC Hybrid Circuit Breaker (HCB). Initially, the principle and construction of the piezoelectric actuator actuating scheme were described and illustrated. A Finite Element Analysis (FEA) model was built to simulate and analyse the presented switch/disconnector static and dynamic behaviours. A prototype was constructed based on calculations, and the travel characteristics were experimentally validated. Subsequently, the proposed switch/disconnector was insulated once in a vacuum and later in a nitrogen gas interruption chamber. Both arrangements were integrated into a DC Hybrid Circuit Breaker test platform to investigate their interruption features. Results show that the presented switch/disconnector achieved a total gap of approximately 1 mm in 1.4 ms and interrupted a DC power of 0.6 kV/60 A within 0.85–1.5 ms in vacuum and 0.98–1.45 ms in nitrogen gas.

Experimental and numerical assessment of GFRP and synthetic fiber reinforced waste aggregate concrete members

Improper disposal of plastic waste (P-waste) poses significant pollution and health risks to the environment. Additionally, steel rebar corrosion in concrete structures reduces their strength and serviceability. To address these issues, this study explores using glass fiber-reinforced polymer (GFRP) rebars and replacing natural coarse aggregates with P-waste aggregates for sustainable and eco-friendly construction. This work investigates the axial performance of polypropylene structural fiber-reinforced P-waste aggregate concrete (SFPC) compressive components having GFRP-reinforcement (GSFPC) under various loading conditions. For comparison, steel-reinforced SFPC compressive components (SSFPC) were also fabricated. Eighteen circular components with 1200 mm height and 300 mm diameter were tested and compared under different loading conditions. SSFPC components exhibited up to 21.9 % higher axial strength but up to 27.4 % lower ductility compared to GSFPC components. Eccentric loading similarly reduced axial strength in both GSFPC and SSFPC components. A 3-D finite element analysis (FEA) of GSFPC components was proposed using a modified damaged plastic model for SFPC which showed deviations of 2.3 % in axial strength and 7.7 % in equivalent axial shortening, demonstrating a good accuracy of the FEA model.

A novel post‐forming method for fully cured thermosetting composite parts: Prediction and investigation

AbstractThe objective of this work is to devise a post‐forming technique capable of accurately and significantly altering the shape of fully cured thermosetting composite parts. To accomplish this goal, the viscoelastic behavior and resulting deformation of fully cured parts at elevated temperatures were predicted and examined using viscoelastic mechanics, finite element analysis (FEA), surrogate modeling, and the particle swarm optimization (PSO) method. Firstly, the mechanism of fully cured parts' shape adjustment based on viscoelastic mechanics was introduced, and a method was established for the inverse identification of the stress relaxation ratio in the different directions of material. Secondly, an FEA model for predicting post‐forming was developed based on the standard linear‐solid viscoelastic model. A dataset was then compiled using parameterized FEA to train a rapid prediction model for post‐forming. The influence of various forming and structural parameters on the post‐forming process was examined. The results indicate that layup has the most significant impact, followed by displacement and temperature. The radial basis function was selected to construct the precise surrogate model after comparing it with the Kriging model and the Response Surface Methodology (RSM) model. Ultimately, to achieve the desired shape after post‐forming, the PSO method can be employed to determine the ideal combination of forming parameters.Highlights The post‐forming method could adjust the shape of fully cured composites. The mechanism of post‐forming is based on viscoelastic behavior. An accurate FEA based on the standard linear‐solid model was established. The radial basis function was developed for quick and precise prediction. The particle swarm optimization could obtain the ideal forming parameters.

Predicting mechanical responses of additively manufactured metamaterials with computational efficiency

Lattice metamaterials, a class of structures utilized for geometric lightweighting and enhancing structural integrity, feature interconnected elements arranged in specific patterns. These patterns confer unique properties beneficial for improving stiffness, damping, energy absorption, and strength across various applications. However, computational simulation of lattice structures for design and optimization presents significant challenges due to nonlinear and elastic/inelastic effects like instabilities, contacts, rate-dependence, and plasticity. Current methods heavily rely on finite element analysis (FEA), yet they entail high computational complexity and do not fully align with experimental observations. Moreover, additive manufacturing (AM) technologies introduce additional computational complexity due to process-induced anisotropic behaviors. This paper proposes a computational model to construct an effective descriptor by integrating metamaterial topological information with AM conditions. This descriptor serves as a surrogate for FEA models. Additionally, a database is established to correlate the descriptor with experimentally acquired mechanical responses of additively manufactured metamaterials. The bidirectional operation of the envisaged descriptor fulfills two objectives: informing the mechanical response of novel metamaterial models and guiding design and AM processes based on desired outcomes. Model validation demonstrates significant concurrence between predicted and experimental results, evidencing the model's capability to capture inherent nonlinearity in both design and process.

Effects of different expansion appliances and surgical incisions on maxillary expansion: A finite element analysis

PurposeThis study aims to assess the impact of different surgical techniques and three expansion appliances on maxillary expansion in adults using finite element analysis (FEA), with a focus on maxillary displacement and stress on surrounding structures. MethodsSeven different FEA models were created to compare different surgical techniques and three different expansion appliances. Model I represented a bone-supported appliance without surgical assistance. Model II, Model III, and Model IV were surgically assisted rapid palatal expansion (SARPE) models without pterygomaxillary suture disjunction (PMD). Model V, Model VI, and Model VII were SARPE models with PMD. ResultsThe largest displacement at the anterior nasal spine (ANS) was recorded for Model II (2.95 mm). For the posterior nasal spine (PNS), the highest displacement was observed in Models V, VI, VII (2.50 mm), with the lowest in Model III (0.79 mm). Stress analysis revealed the highest stress in Model I, with models featuring PMD displaying nearly zero stress at all anatomical points, highlighting distinct expansion patterns and stress distributions between models with and without PMD. ConclusionSARPE models with PMD demonstrated a parallel expansion of the maxilla with minimal stress, while the miniscrew assisted rapid maxillary expansion (MARPE) model displayed transverse rotation. SARPE models without PMD exhibited a V-shaped expansion pattern. SARPE models with PMD represent an optimal approach for achieving uniform expansion and minimizing stress, with stress levels nearly negligible at all anatomical points in models with PMD.

Effect of margin designs and loading conditions on the stress distribution of endocrowns: a finite element analysis

BackgroundMargin designs and loading conditions can impact the mechanical characteristics and survival of endocrowns. Analyzing the stress distribution of endocrowns with various margin designs and loading conditions can provide evidence for their clinical application.MethodsThree finite element analysis models were established based on the margin designs: endocrown with a butt-joint type margin (E0), endocrown with a 90° shoulder (E90), and endocrown with a 135° shoulder (E135). The E0 group involved lowering the occlusal surface and preparing the pulp chamber. The E90 group created a 90° shoulder on the margin of model E0, measuring 1.5 mm high and 1 mm wide. The E135 group featured a 135° shoulder. The solids of the models were in fixed contact with each other, and the materials of tooth tissue and restoration were uniform, continuous, isotropic linear elasticity. Nine static loads were applied, with a total load of 225 N, and the maximum von Mises stresses and stress distribution were calculated for teeth and endocrowns with different margin designs.ResultsCompared the stresses of different models under the same loading condition. In endocrowns, when the loading points were concentrated on the buccal side, the maximum von Mises stresses were E0 = E90 = E135, and when there was a lingual loading, they were E0 < E90 = E135. In enamel, the maximum von Mises stresses under all loading conditions were E0 > E90 > E135. In dentin, the maximum von Mises stresses of the three models were basically similar except for load2, load5 and load9. Compare the stresses of the same model under different loading conditions. In endocrowns, stresses were higher when lingual loading was present. In enamel and dentin, stresses were higher when loaded obliquely or unevenly. The stresses in the endocrowns were concentrated in the loading area. In enamel, stress concentration occurred at the cementoenamel junction. In particular, E90 and E135 also experienced stress concentration at the shoulder. In dentin, the stresses were mainly concentrated in the upper section of the tooth root.ConclusionStress distribution is similar among the three margin designs of endocrowns, but the shoulder-type designs, especially the 135° shoulder, exhibit reduced stress concentration.

Design and Analysis of Novel Anti-Rocking Bearing

To address the issue of severe rocking phenomena under seismic conditions in structures equipped with steel spring isolation bearings, this paper investigates a novel type of anti-rocking bearing. Firstly, the structural configuration and working principle of the novel anti-rocking bearing are introduced, and a design method for bearing parameters is proposed. Secondly, a finite element analysis model is established using SAP2000-v20 software to conduct nonlinear dynamic time–history analysis under seismic loading. The analysis results show that the structural arrangement of the novel anti-rocking bearing reduces both the vertical displacement difference and the rocking angle of the isolation layer. The bearing exhibits a certain level of anti-rocking effect, but it may cause significant tensile forces in some bearings. The effectiveness of the anti-rocking effect improves as the stiffness of the steel tension rod in the bearing increases. For structures equipped with the novel anti-rocking bearing, the acceleration amplifies under most cases, with amplification coefficients ranging from 0.82 to 1.55. Through the finite element simulation of the bearing, the mechanical properties of the bearing are essentially the same as the theoretical analysis results.

A Patient-Specific Morphoelastic Growth Model of Aortic Dissection Evolution.

The human aorta undergoes complex morphologic changes that indicate the evolution of disease. Finite element analysis enables the prediction of aortic pathologic states, but the absence of a biomechanical understanding hinders the applicability of this computational tool. We incorporate geometric information from computed tomography angiography (CTA) imaging scans into finite element analysis (FEA) to predict a trajectory of future geometries for four aortic disease patients. Through defining a geometric correspondence between two patient scans separated in time, a patient-specific FEA model can recreate the deformation of the aorta between the two time points, showing pathologic growth drives morphologic heterogeneity. A shape-size geometric feature space plotting the variance of the shape index versus the inverse square root of aortic surface area (δ𝒮 vs. ) quantitatively demonstrates the simulated breakdown in aortic shape. An increase in δ𝒮 closely parallels the true geometric progression of aortic disease patients.

Evaluation of the vacuum effect on headspace solid-phase microextraction of volatile organic compounds from aqueous samples using finite element analysis modeling

Headspace solid-phase microextraction (HSSPME) of volatile organic compounds (VOCs) from aqueous samples under vacuum conditions (Vac-HSSPME) allows increasing extraction rates and decreasing detection limits compared to HSSPME under atmospheric pressure. The positive effect of the vacuum on HSSPME of an analyte can be quickly estimated using its Henry's law constant (HLC). According to the two-layer model of evaporation, substantial positive effect of the vacuum can be expected for analytes with HLC lower than 1.6·10−4 atm m3 mol−1 (0.0065 at 25 °C), but the model does not consider possible effects of other important extraction parameters. This research was aimed at the evaluation of the possible effect of vacuum on the equilibration time and extracted amounts of analytes with various HLC and fiber coating-headspace distribution constants (Kfh) using the computational model recently developed in COMSOL Multiphysics® software. It has been proven that HSSPME under vacuum provides faster equilibration of VOCs with all studied Kfh and HLC. The largest vacuum effect on the extracted analyte amount was 3.9–4.0 times at logKfh = 6 and HLC = 10−6–10−3. The substantial (≥1.5 times) vacuum impact should not be expected for analytes with logKfh < 5 for 15-min extraction and logKfh < 5.5 for 30-min extraction. The vacuum impact should be more pronounced when using fiber coatings with a stronger affinity to analytes. The obtained results will be useful for the development of new methods based on Vac-HSSPME and evaluation whether HSSPME is reasonable to conduct under vacuum conditions for faster equilibration and/or lower detection limits.

Structural optimization using a genetic algorithm aiming for the minimum mass of vertical axis wind turbines using composite materials

A wind turbine comprises multiple components constructed from diverse materials. This complexity introduces challenges in designing the blade structure. In this study, we developed a structural optimization framework for Vertical Axis Wind Turbines (VAWT). This framework integrates a parametric Finite Element Analysis (FEA) model, which simulates the structure's global behavior, with a Genetic Algorithm (GA) optimization technique that navigates the design domain to identify optimal parameters. The goal is to minimize the mass of VAWT structures while adhering to a suite of complex constraints. This framework quantifies the mass reduction impact attributable to material selection and structural designs. The optimization cases indicate that blades made from Carbon Fiber Reinforced Plastics (CFRP) materials are 47.1 % lighter than those made from Glass Fiber Reinforced Plastics (GFRP), while the structural parts are 44.8 % lighter. This work also provides further recommendations regarding the scale and design of the structures. With the materials and structural design established, future studies can expand to include more load cases and detailed designs of specific components.

Predictive modeling of wide-shallow RC beams shear strength considering stirrups effect using (FEM-ML) approach

This paper presents an analysis and prediction of the shear strength of wide-shallow reinforced concrete beams, utilizing Finite Element Analysis (FEA) and machine learning techniques. The methodology involves validating a detailed Finite Element Model (FEM) against experimental results, conducting a parametric study, and developing three Machine Learning prediction equations. The FEM captures concrete and steel behaviors, including cracking and crushing for concrete and linear isotropic properties for steel reinforcement. Loading and boundary conditions are defined for accuracy and validated against 13 experimental specimens, exhibiting a maximum 8% and 12% difference in loads and deflections, respectively. A parametric study generates a dataset of 77 wide beam configurations, exploring variations in beam widths, concrete strengths, compression rebars, and shear reinforcement. This dataset is used to develop machine learning models, including “Genetic Programming (GP)”, “Evolutionary Polynomial Regression (EPR)”, and “Artificial Neural Network (ANN)”. Comparative analysis reveals GP and EPR models with over 95% correlation, while the ANN model outperforms with 99% accuracy. Sensitivity analysis underscores the significant influence of concrete strength and beam aspect ratio on shear strength. In conclusion, the study demonstrates the potential of FEA and machine learning models to predict shear strength in wide-shallow reinforced concrete beams, providing valuable insights for architectural design and engineering practices and emphasizing the role of concrete strength and beam geometry in shear behavior.

Seismic performance evaluation of precast post-tensioned high-performance concrete frame beam-column joint under cyclic loading

Precast concrete structures have developed rapidly because they meet the requirements of green and low-carbon social development. In this paper, a precast post-tensioned high-performance concrete frame beam-column joint was proposed, and the low-cycle reversed load test was performed on the four proposed joints. The main differences between the four joints are the different prestress values applied by the joints and whether the beam-column joint is provided with L-shaped steel. The seismic performance indexes such as hysteresis curve, stiffness degradation, deformation capacity, energy dissipation capacity and residual deformation of each node were obtained through experiments. By comparing various seismic performance indicators, it could be found that the use of high-performance concrete could effectively avoid the phenomenon of local crushing of concrete due to excessive prestressing. At the same time, it was found that the setting of L-shaped steel plate at the beam-column junction could effectively avoid the early damage at the beam-column junction. On the basis of the test, the three-line restoring force model of the joint was established by the method of experimental regression analysis. The model could better reflect the stress situation of each stage of the joint. Based on the experimental and theoretical analysis, the finite element analysis model of the joint was established, and the model calculation results were in good agreement with the experimental results.

Enhancing thermal management efficiency in robotics engineering: Exploring mechanisms, techniques, and modeling approaches

Thermal management is pivotal in robotics engineering, ensuring optimal performance and reliability of robotic systems. This comprehensive review explores various heat dissipation mechanisms, cooling techniques, and thermal modeling approaches employed in robotics engineering. Key topics include conduction-based, convection-based, and radiation-based heat transfer mechanisms, alongside liquid cooling, air cooling, and phase-change cooling techniques. Analytical thermal models, computational fluid dynamics (CFD) simulations, and finite element analysis (FEA) modeling are discussed for their roles in predicting thermal behaviors and optimizing heat dissipation strategies. By synthesizing these advancements, this review provides valuable insights into enhancing thermal management efficiency and ensuring the longevity of robotic systems.

Influence of process parameters on forming quality of largesize nickel-based alloy tubes

In order to improve the forming quality of largesize nickel-based alloy chemical tubes, the influence of different tube specifications and mandrel/tube clearances on the bending forming quality of largesize Hastelloy C-276 alloy tubes was studied. A finite element (FE) analysis model for NC rotary drawing bending (RDB) was established and verified. The results show that with the increasement of the clearance, the wall-thinning ratio [Formula: see text] of different tube specifications gradually decreases, and the wall-thickening ratio [Formula: see text] and ovality [Formula: see text] gradually increase. As the measuring angle increases, the [Formula: see text] of different specifications initially increases and then decreases. The [Formula: see text] exhibits a trend of initially increasing and then decreasing. It is reasonable to take about 1/8 of the wall thickness t for the mandrel/tube clearance. It is of great significance for guiding the bending forming of largesize nickel-based alloy chemical tubes and development of intelligent forming equipment.

Bending forming of lightweight large diameter thin-walled aluminum alloy aviation tube

To improve the forming quality of lightweight aviation tubes, the influence of different tube specifications, forming requirements and process parameters on bending forming of large diameter thin-walled (LDTW) LF2M aluminum alloy tubes (AATs) was studied. A finite element analysis model for LDTW AAT bending was established and verified. The results show that with the increase of mandrel extension length [Formula: see text], the wall-thinning ratio tends to increase. With the increase of [Formula: see text], the overall wall-thickening ratio decreases. With the increase of [Formula: see text], the ovality decreases first and then increases. The bending radius has a great influence on wall thickness variation. It has great significance to guide the bending forming of lightweight LDTW aluminum alloy aviation tube.

Increased stability of short femoral stem through customized distribution of coefficient of friction in porous coating

Stress shielding and aseptic loosening are complications of short stem total hip arthroplasty, which may lead to hardware failure. Stems with increased porosity toward the distal end were discovered to be effective in reducing stress shielding, however, there is a lack of research on optimized porous distribution in stem’s coating. This study aimed to optimize the distribution of the coefficient of friction of a metaphyseal femoral stem, aiming for reducing stress shielding in the proximal area. A finite element analysis model of an implanted, titanium alloy short-tapered wedge stem featuring a porous coating made of titanium was designed to simulate a static structural analysis of the femoral stem's behavior under axial loading in Analysis System Mechanical Software. For computational feasibility, 500 combinations of coefficients of friction were randomly sampled. Increased strains in proximal femur were found in 8.4% of the models, which had decreased coefficients of friction in middle medial areas of porous coating and increased in lateral proximal and lateral and medial distal areas. This study reported the importance of the interface between bone and middle medial and distal lateral areas of the porous coating in influencing the biomechanical behavior of the proximal femur, and potentially reducing stress shielding.

Failure analysis of wellhead casing and optimization of slip hanger in ultra deep wells

When replacing the sealing element and lifting the oil production spool in a certain oilfield in Xinjiang, it was found that the casing at the clamping point of the wellhead hanger slip was broken. Based on the Ф232.5 mm W-type slip hanger structure used in the X1 well on site, a three-dimensional finite element model of the casing’s grip by the slip hanger was established. Firstly, based on the third and fourth strength theories, the calculation formula for the ultimate load of the casing under the slip effect was derived. Furthermore, tensile experiments, chemical composition measurements, and microstructure analysis were conducted on the 155 V casing samples used, and it was found that the performance of the 155 V casing material meets the standard requirements, the data suggests that the slip may contribute to casing fracture, warranting further investigation. Therefore, based on the mechanical finite element analysis model, it is calculated that the maximum stress on the outer wall of the casing reaches 1146 MPa, which is higher than the yield strength of the 155 V casing. This will lead to the damage of the casing used on site. Therefore, the structure of the slip is optimized, and the analysis shows that the top of the slip tooth is optimized to have a long axis of 400 mm, the one-fourth elliptical distribution with a short axis of 1 mm and the optimization of the top angle of the slip teeth to 60°–70° will significantly decrease the maximum stress on the outer wall of the casing. However, the optimization scheme of changing the inclination angle of the slip teeth and increasing the clearance of the slip back cone angle cannot effectively improve the stress distribution and maximum value on the outer wall of the casing.

Biomechanical assessment of mandibular fracture fixation using finite element analysis validated by polymeric mandible mechanical testing

The clinical finite element analysis (FEA) application in maxillofacial surgery for mandibular fracture is limited due to the lack of a validated FEA model. Therefore, this study aims to develop a validated FEA model for mandibular fracture treatment, by assessing non-comminuted mandibular fracture fixation. FEA models were created for mandibles with single simple symphysis, parasymphysis, and angle fractures; fixated with 2.0 mm 4-hole titanium miniplates located at three different configurations with clinically known differences in stability, namely: superior border, inferior border, and two plate combinations. The FEA models were validated with series of Synbone polymeric mandible mechanical testing (PMMT) using a mechanical test bench with an identical test set-up. The first outcome was that the current understanding of stable simple mandibular fracture fixation was reproducible in both the FEA and PMMT. Optimal fracture stability was achieved with the two plate combination, followed by superior border, and then inferior border plating. Second, the FEA and the PMMT findings were consistent and comparable (a total displacement difference of 1.13 mm). In conclusion, the FEA and the PMMT outcomes were similar, and hence suitable for simple mandibular fracture treatment analyses. The FEA model can possibly be applied for non-routine complex mandibular fracture management.

Multi-objective optimization of rivet and die for self-piercing riveting using finite element analysis

This study numerically investigated the effects of self-piercing riveting (SPR) process parameters on the quality of joints between steel and aluminum alloy sheets. First, the mechanical properties of each metal were experimentally evaluated, and a single-lap shear test was performed to validate a constructed finite element analysis model. This model was subsequently applied to optimize the die depth, die radius, and rivet length parameters of the SPR process using a multi-objective optimization method considering the shear strength, interlocking distance, and minimum thickness of the bottom sheet as objective functions. The results indicated that the maximum interlock distance was achieved with a longer die depth and larger die radius, and the largest minimum thickness of the bottom sheet was achieved with a shorter rivet length and larger die depth and radius. The die radius and depth were determined to be the most critical variables for all objective functions. The findings of this study can be applied to optimize the SPR of steel and aluminum alloy sheets.

Digital fatigue cracking test and fatigue life assessment of rib-deck joints in orthotropic steel decks

The orthotropic steel decks (OSDs) are vulnerable to fatigue fractures, which will inevitably impair the normal service of the steel bridge panels. To determine the impact of the initial cracks on the fatigue life, this study constructed an evaluation model of the OSD rib-to-deck joints crack based on the fracture mechanics principle. And combined it with the multi-scale finite element analysis model, the digital fatigue test model of the whole bridge was established. Research shows: A typical I-II-III composite crack with the supremacy of type I crack can be seen in the OSD rib-to-deck joints. Fatigue cracks developed at the deck weld toe dominate the fatigue failure mode. Further research revealed that as the depth of cracks increased, the stress on the cross-section was redistributed. The intensity factor then displayed a trend of growing and then gradually flattening or even dropping. Based on the relationship between cracks of different depths and the remaining life of the OSDs, recommendations are given for bridge maintenance. The multi-scale digital fatigue test can provide analysis and simulation methods for the fatigue crack propagation in the steel bridge deck of the bridge in operation.