Element Analysis Research Articles

Brittle failure analysis and modeling of high-burnup PWR fuel cladding alloys

Abstract The aim of this research is the development of methods for predicting mechanical behavior and identification of limiting conditions to prevent brittle failure of high-burnup (HBU) pressure water reactor (PWR) fuel cladding alloys. A finite element (FE) model of the ring compression test (RCT) was created to analyze the failure behavior of zirconium-based alloys with radial hydrides during the RCT. An elastic-plastic material model describes the zirconium alloy. The stress-strain curve needed for the elastic-plastic material model was derived by inverse finite element analyses. Cohesive zone modeling is used to reproduce sudden load drops during RCT loading. Based on the failure mechanism in non-irradiated ZIRLO® claddings, a micro-mechanical model was developed that distinguishes between brittle failure along hydrides and ductile failure of the zirconium matrix. Two different cohesive laws representing these types of failure are present in the same cohesive interface. The key differences between these constitutive laws are the cohesive strength, the stress at which damage initiates, and the cohesive energy, which is the damage energy dissipated by the cohesive zone. Statistically generated matrix-hydride distributions were mapped onto the cohesive elements and simulations with focus on the first load drop were performed. Computational results are in good agreement with the RCT results conducted on high-burnup M5® samples. It could be shown that crack initiation and propagation strongly depend on the specific configuration of hydrides and matrix material in the fracture area.

Assessment of capacitor bank configuration of self-Excitation in induction generators utilizing finite element analysis

Self-excited induction generators (SEIGs) require carefully designed capacitor banks to maintain stable operation. This paper compares a capacitor bank design approach based on general parameters with one derived from the magnetizing reactance of three-phase induction generators. Finite element method simulations in Simulink are used to analyze and optimize the performance of these capacitor bank configurations. The results provide insights into the most effective designs for achieving reliable self-excitation in induction generators.

Extending Generalized Explicit Terms and Applying Euler–Bernoulli Beam Theory to Enhance Dynamic Response Prediction in Receptance Coupling Method

This paper presents a theoretical framework to enhance the prediction of dynamic responses in complex mechanical systems, such as vehicle structures, by incorporating both translational and rotational degrees of freedom. Traditional receptance coupling methods often neglect rotational effects, leading to significant inaccuracies at higher frequencies. Additionally, approaches that implicitly include full dynamics frequently result in redundancy of generalized coordinates, especially at connection points. To address these limitations, the generalized receptance coupling method using Frequency-Based Substructuring is extended to explicitly account for rotational dynamics resulting in a refined GRCFBS approach. This extension enhances both the understanding and prediction of system responses, which are represented through the receptance matrix or Frequency Response Function. Building on Jetmundsen’s foundational work, the proposed framework introduces a practical, generalized formulation that explicitly incorporates full translational and rotational dynamics at each substructure node. This explicit definition provides deeper insights into system behavior, particularly for complex interactions between substructures under weak and strong coupling scenarios at interface points. The Euler–Bernoulli beam theory is employed to model rotational behavior at critical points, yielding reduced-order and explicit receptance matrices for substructures in the coupling process. The methodology’s accuracy and applicability in capturing resonance and anti-resonance modes are validated through two case studies: the coupling of two flexible subsystems and the integration of flexible and rigid components. Results are benchmarked against numerical finite element analysis, and all limitations and potential improvements are discussed. By directly incorporating rotational dynamics directly, this approach enables more reliable dynamic response predictions under multi-directional loading conditions, particularly for vehicle and machinery system design. The GRCFBS method offers a versatile and reliable tool for dynamic system analysis, with significant potential for vibration analysis over a broad frequency range.

Evaluation of stress distribution in coronal base and restorative materials: A narrative review of finite element analysis studies

Background: Analyzing the stresses created by functional and parafunctional forces on teeth, bones, soft tissues, and intraoral dental materials is crucial for enhancing the success and development of restorations. Purpose: The purpose of this review is to evaluate studies that examine stress distribution in coronal base and restorative materials using the method of finite element analysis. Review: The three-dimensional finite element analysis method is extensively utilized to study biomechanical behavior and assess stress distribution within dental materials. Numerous studies from 2010 to 2024 have investigated the stress caused by polymerization shrinkage and the distribution of stress in various base and restorative materials. Conclusion: This review emphasizes findings related to stress distribution in coronal base and restorative materials, stressing the importance of considering the elastic modulus and thickness of base materials, and highlighting the need for additional research in this field.

水稻籽粒堆积特性离散元法模拟研究

Accurately determining the angle of repose for irregular and dispersed agricultural grain materials requires a simulation model that effectively represents the actual grain shapes and utilizes numerical methods to analyze their stacking behavior. This study focuses on "Yongyou 15" rice grains, employing 3D raster scanning technology to obtain precise contour data. Through a reverse modeling process, a detailed 3D geometric model of the grains was developed, resulting in a discrete element model comprising 618 grains of varying diameters, created using granular polymer theory. Discrete element analysis software (EDEM) was integrated with MATLAB image processing to simulate the falling and stacking process of the rice grains within a stainless steel bottomless cylindrical tube. The contour of the grain heap was analyzed using linear fitting, followed by a micro-mechanical investigation of the grain heap structure. The analysis indicated that the pressure depression within the heap is caused by the oblique transmission of contact forces. The simulated angle of repose under experimental conditions was 31.29°±0.41°, differing by only 0.81% from the actual measured angle of 31.04°±0.21° obtained through physical stacking experiments. These results demonstrate that combining numerical simulations with image feature extraction is a reliable and efficient method for assessing the stacking properties of agricultural materials.

Biomechanical stability of magnesium plate and screw fixation systems in LeFort I osteotomy: a three-dimensional finite element analysis

BackgroundTitanium (Ti–6Al–4 V) is used for fixation in LeFort I osteotomy, a procedure for treating midface deformities. This study assessed the biomechanical stabilities of two Mg alloys (WE43 and ZK60) as biodegradable alternatives and compared them against Ti using finite element analyses. The LeFort I osteotomy procedure was simulated, and various plate and screw configurations were tested. The maximum principal and peak von Mises stresses in the metal plates and bone screws were measured under four load conditions, and the stability was evaluated.ResultsThe holes in the Mg screws, as compared with the Ti counterparts, exhibited higher and lower stress levels in the cortical and cancellous bones, respectively. The Mg screws also exhibited a higher fracture risk. The ZK60 plate, as compared with the Ti and WE43 plates, exhibited a lower fracture risk under all load conditions. ZK60 exhibited higher biomechanical stability in terms of maintaining the gap between osteotomy surfaces and lower fracture risk; the osteotomy surfaces with Ti im-plants underwent bone impaction, resulting in gap closure.ConclusionsAlthough the Mg implants exhibited better stress distribution, their screw strength requires improvement. Appropriate improvements can promote the use of Mg alloys in bone fixation applications.

A Piezoelectric Coded-Excitation Scanning Acoustic Transducer for Lamb Wave Inspections

Abstract Several techniques for Guided Wave (GW) inspections have already been developed. Most of them rely on extensive sensor deployment and damage localization algorithms characterized by significant computational costs. However, there is a growing demand for simpler, more autonomous, and more affordable systems across various fields. In particular, the implementation of wireless, battery-powered systems with a reduced number of sensor nodes and simpler processing would greatly facilitate the transition of this inspection technology on the field. Following this direction, this work presents the design of a novel piezoelectric transducer composed of four different patches, i.e. with only four input/output channels, to scan a given area. The peculiar piezo-load distributions allow the association of different spectral binary sequences for each 6° discrete angular step. Since the transducer is designed as an encoder, it is referred to as Coded-Excitation Scanning Acoustic Transducer (CESAT). More specifically, the Gray Code is used to generate spectral patterns to reduce the uncertainty between two adjacent angular steps. A new quantization procedure for the optimal generation of the piezo distributions is also proposed. Ad hoc signal processing algorithms, suitable for embedded applications, were developed to extract multi-target range and angle information. The processing is based on the frequency decomposition of the recorded signal using an FIR filter bank and on dispersion compensation procedures for pulse "re-compression". The transducer encoder behaviour is validated through a Finite Element (FE) analysis. Finally, numerical simulations were performed to assess the effectiveness of the CESAT and associated signal processing in multi-defect detection and localization tasks.

A Multi-layer Parallelogram Flexure Architecture for Higher Out-of-Plane Load Bearing Stiffness

Abstract Parallelogram Flexure Mechanism (PFM) is a common flexure module which is widely used as a building block in the design and manufacturing of flexure-based XY motion stages that provide in-plane Degrees of Freedom (DoFs). In such motion stages, low in-plane stiffness along the DoF helps increase the DoF range of motion and reduce the actuation effort. At the same time, high out-of-plane stiffness is paramount to suppress out-of-plane parasitic motions, support heavy payloads and mitigate the negative impacts of out-of-plane resonant modes. Achieving both of these design objectives simultaneously is extremely challenging in PFMs and flexure mechanisms comprising PFMs due to the inherent tradeoff between the in-plane and out-of-plane stiffness. This paper resolves this tradeoff by proposing a novel multi-layer PFM architecture, referred to as the sandwich PFM, that achieves a significant improvement in the out-of-plane translational and rotational stiffness compared to conventional single-layer PFMs without impacting the in-plane DoF stiffness. Analytical models will be derived for the in-plane and out-of-plane stiffness of the sandwich PFM that closely match with the Finite Element Analysis (FEA) results. Several design insights into the performance of the sandwich PFM are discussed using the analytical stiffness models and a general procedure is proposed to design a sandwich PFM.

Biomechanical and Injury Tolerance Analysis of Tibial Movement Under Different Postures and Impact Loads

The lower limbs play an important role in daily human activities. Therefore, a 3D tibial model is constructed, and finite element analysis is performed to investigate the biomechanical characteristics and injury tolerance of lower limb flexion movement. The maximum equivalent stress at 30° flexion was 19.1 MPa and 31.2 MPa in the normal and dynamic eversion positions, respectively, of the knee joint, 1.4 MPa and 1.1 MPa in the medial tibial plateau, and 1.8 MPa and 1.2 MPa in the lateral tibial plateau. The peak contact force was generally approximately 4000 N when different positions of the tibia were impacted. The maximum contact force of the frontal impact was larger than that of the external impact at 4109 N and 3927 N, respectively. The dynamic knee valgus posture and lateral impacts are more likely to cause tibial injury. The findings of this study provide information for the prevention of sports injuries and rehabilitation treatment.

Physics-guided machine learning enhanced electrostatic actuated method for in-situ measurement of Young’s modulus

Abstract Young's modulus of polysilicon is a vital mechanical parameter highly dependent on sample preparation and growth techniques. In-situ measurement of this property is essential for effective process control monitoring in MEMS fabrication. In this work, an innovative electrostatic actuated method without pull-in instability for in-situ test is proposed. Based on the behavior simulated through finite element analysis, physics-guided neural networks which integrate the advantage of both data science models and physics-guided ones are utilized to extract the Young’s modulus and assess the probability of pull-in instability. Moreover, the performance of structure is evaluated and optimized through Pareto analysis based on genetic algorithm. It is found that the mapping relationship between systematic parameters, excitation, and response of the structure can be modeled by physics-guided neural network accurately, and the optimization of design facilities the convenience of measurement. Moreover, error of this method is within 5% under most circumstances, and the measured Young’s modulus through this method is close to that by nanoindentation test. This work explores potential applications of machine learning in MEMS design, testing, and optimization.

Strengthen of metal-polymer direct molding bonding via three-dimensional porous mechanical interlocking

This paper proposes a direct metal–polymer forming–bonding method using three-dimensional (3D) porous mechanical interlocking to achieve high-strength metal–polymer connections. In this method, porous copper is initially sintered onto copper plates, followed by the infusion of molten polymer into the pores, forming a robust copper–polymer bonded structure. Incorporating microneedle arrays into the copper plates further enhances the bond between the porous copper and the polymer. Characterization of the pore morphology and mechanical properties confirmed the formation of large-area 3D micro-interlocking. Tensile tests on samples with varying porosities showed connection strengths exceeding 30 MPa, with a maximum recorded strength of 37 MPa. Finite element analysis supported the high bonding strength and provided insights into failure mechanisms. This cost-effective technique offers superior copper–polymer bonding strengths, and introduces novel concepts for composite heat exchanger design and manufacturing.

Crack Propagation and Fatigue Life Analysis of Wind Turbine Blades

This dissertation investigates the fatigue and fracture behaviour of wind turbine blades exposed to varying wind speeds and load intensities, aiming to enhance their durability and operational lifespan in sustainable energy systems. The increasing reliance on wind energy underscores the need for durable blades that can withstand cyclic loads and extreme environmental conditions, as fatigue and fracture failures significantly impact maintenance costs and reliability. This research specifically examines fatigue life and fracture initiation at wind speeds of 15 m/s and 60 m/s, analysing the effects of increased load intensities (30 MPa and 62 MPa). Finite Element Analysis (FEA) through ANSYS is employed to model fatigue and fracture dynamics, incorporating fatigue life prediction using S-N curves, stress analysis with von Mises stress, and crack propagation simulation via fracture mechanics principles, such as Paris’ Law. Results reveal a notable reduction in fatigue life with increased loads, evidenced by a drop from 9e09 to 7.9e08 cycles at 15 m/s, with comparable fatigue cycle reductions at 60 m/s. Fracture analysis identifies critical crack initiation points in high-stress areas, and simulations indicate the progressive nature of crack propagation under cyclic loads. These findings underscore the importance of integrating fatigue and fracture assessments in the design and maintenance strategies of wind turbine blades to enhance resilience and support the sustainable advancement of wind energy systems.

A ferromagnetic notched soft guidewire for enhanced flexibility

Abstract Ferromagnetic soft guidewires (FSGs) capable of remote active steering and navigation offer substantial potential for biomedical applications. However, in practical applications, such as tasks requiring navigation through large-angle bends in narrow spaces and carrying loads, the performance of FSG is limited. This paper presents a design framework for ferromagnetic notched soft guidewires (FNSGs) that significantly enhances steering performance while maintaining sufficient stiffness. Then, an modified segmented Cosserat rod model is proposed and validated through finite element analysis and experiments, providing an effective tool for the analysis of FNSGs. Moreover, analysis of the workspace and the bending stiffness is conducted on FNSG design with different notch geometric parameters, revealing that the notches have a significant impact on the deflection of FNSG along different directions. Finally, the superior performance of the FNSG in navigation, maneuvering through large-angle bends, and bearing heavy loads was demonstrated through an integrated magnetic field system.

Review on finite element analysis of meso-structure model of concrete

Review on finite element analysis of meso-structure model of concrete

Automated bone property analysis using corrected in vivo dental cone-beam CT data of human wrists

Fracture liaison services are essential to mitigate underdiagnosis and undertreatment of osteoporosis-related fractures. However, it often suffers from limited access to dual-energy X-ray absorptiometry (DXA) or high-resolution peripheral quantitative CT equipment. This in vivo study of 21 patients aims to evaluate the feasibility of dental cone beam CT (dCBCT) to analyse bone properties of human wrists, comparing with DXA and finite element (FE) analysis. dCBCT grey-scale values were transformed to HU using a phantom containing materials with known HU values. Strong correlations were found between bone mineral content (BMC) from dCBCT and DXA (r = 0.78 to 0.84, p < 0.001), as well as between BMC from dCBCT FE-predicted stiffness (r = 0.91) and maximum force (r = 0.93), p < 0.001. BMC values from dCBCT were higher than DXA measurements (2.34 g vs. 1.5 g, p < 0.001). Cortical thickness strongly correlated to bone mineral density (BMD) from dCBCT (r = 0.83, p < 0.001). No statistically significant correlations were found between trabecular bone microstructure and FE predictions. The results indicate the feasibility to analyse osteoporosis related bone properties of human wrists from corrected dCBCT data. The dCBCT values of BMD and BMC were strongly correlated with DXA.

Advanced Design Validation Planning Techniques for Commercial Vehicle E-Axles

&lt;div&gt;Design validation plays a crucial role in the overall cost and time allocation for product development. This is especially evident in high-value manufacturing sectors like commercial vehicle electric drive systems or e-axles, where the expenses related to sample procurement, testing complexity, and diverse requirements are significant.&lt;/div&gt; &lt;div&gt;Validation methodologies are continuously evolving to encompass new technologies, yet they must be rigorously evaluated to identify potential efficiencies and enhance the overall value of validation tests. Simulation tools have made substantial advancements and are now widely utilized in the development phase. The integration of simulation-based or simulation-supported validation processes can streamline testing timelines and sample quantities, all the while upholding quality standards and minimizing risks when compared to traditional methods. This study examines various scenarios where the implementation of advanced techniques has led to a reduction in the e-axle design validation plan (DVP), particularly in relation to the start of production (SOP) decision-making quality gates.&lt;/div&gt; &lt;div&gt;Many DVPs incorporate tests in a specific order to enhance the validation impact of each sample and to guarantee that preconditioning tests are implemented when necessary. An instance of preconditioning is subjecting a system to thermal cycling. Thermal cycle preconditioning ensures that the sample accurately represents a real-world system when undergoing sealing-related tests, such as ingress protection testing according to ISO 20653 [&lt;span&gt;1&lt;/span&gt;]. Assessing the necessary thermal cycling to “bed-in” a sample would be highly elaborate using a physical sample, but it is a straightforward aspect to extract from modern finite element analysis (FEA). A case study will be presented to evaluate the minimum required thermal cycling and determine the cost savings for the DVP.&lt;/div&gt; &lt;div&gt;Furthermore, the validation supported by simulations will be showcased in the context of accelerated lifetime testing. Often, accelerating such tests necessitates a balance between the distribution of damages and the overall testing duration. By incorporating safety factors from simulations as an initial input, the distribution of damages can be adjusted to allow for some over-testing on more secure components, thereby reducing the overall testing time.&lt;/div&gt; &lt;div&gt;Efficiency assessment will additionally be considered for virtual validation due to the complexity of the measurement and data acquisition, contributing to measurement uncertainty. Furthermore, simulation-based validation will be considered for the case of lubrication testing, which can be hampered by a largely qualitative assessment criteria.&lt;/div&gt; &lt;div&gt;Overall, these scenarios will be evaluated for their potential to streamline the overall DVP process in terms of testing time, sample quantity, and critical path duration. This underscores the potential benefits of leveraging advanced DVP techniques for cost and time savings.&lt;/div&gt;

INFLUENCE OF ADDITIVE MANUFACTURING TECHNOLOGY OF TOPOLOGICALLY OPTIMIZED PRODUCTS FROM PHOTOPOLYMER RESINS ON THE ANISOTROPY OF THEIR MECHANICAL PROPERTIES

This article discusses the problem of ensuring strength and minimum mass in the design of products manufactured using additive technologies. The authors investigated the possibility of using topological optimization in computer-aided design systems to create an optimized model with the necessary strength at a minimum weight. As part of the work, the topological optimization of the bracket, the production of its samples by additive manufacturing methods and strength tests were carried out. The optimal values were found via finite element analysis using the SolidWorks and ANSYS software. The calculation results show that the optimized model retains about 20% of the original mass and has the necessary mechanical characteristics. In particular, the excess safety margin is reduced by 2.5 times, which is acceptable for this bracket. The subsequent verification of the models is carried out through destruction tests of the products manufactured using additive technologies, i.e. the method of filament deposition and stereolithography. To account for the anisotropy of the material, a series of samples oriented at different angles to the direction of construction was made. The tests were carried out on a test bench for simultaneous biaxial stretching, which corresponds to the design loads on the bracket. An increase in the tensile load on the sample was carried out before its destruction. In the course of the work, the presence of anisotropy of mechanical properties was revealed, and optimization results in various software packages were studied. The results of strength tests allow us to draw two conclusions. Firstly, due to the anisotropy of the material, the strength properties significantly depend on the orientation of the bracket during additive manufacturing. Secondly, the bracket, optimized by means of the SolidWorks software package, generally showed the best strength properties for various orientations during manufacturing. Also, which is quite expected, the samples obtained by stereolithography showed less anisotropy than the samples obtained by the method of filament deposition. In conclusion, it is noted that the use of additive technologies to create optimized forms requires considering printing technologies and anisotropy of properties, as well as the choice of appropriate software.

COMPACT ANALYTICAL MODEL FOR ELECTROMAGNETIC DISK-SHAPED UNDERWATER TRANSDUCER

This paper proposes a mathematical model for a disk-type pulsed electrodynamic transducer operating in the low-frequency range. A well-known architecture of an electromagnetic acoustic radiator with a helical coil and a conducting disk is studied. In the work, the equations of the electromechanical system in the form of the Lagrange-Maxwell equations are built with the use of the Green's functions of a plane axisymmetric acoustic problem to estimate the reaction force of the fluid. A comparison is made between the results of a numerical solution of the obtained equations and direct numerical calculation in the COMSOL finite element analysis software. The resulting model shows good qualitative agreement with the results of finite element calculations while allowing calculations with a variation for all main model parameters required to design the transducer.

Investigating Tensile Strength in SLA 3D Printing Enhancement Through Experimentation and Finite Element Analysis

Additive manufacturing, particularly Stereolithography (SLA) 3D printing, has emerged as a promising technology for producing complex and customized components. This study investigates the optimization of tensile strength in SLA 3D printed resin through a comprehensive experimental and computational analysis. Utilizing a multilevel factorial design approach, the study systematically evaluates the influence of print orientation and layer orientation on tensile strength. Experimental testing, conducted using an Instron 5566 machine, reveals that a print orientation of 22.5 degrees and side orientations yield the highest tensile strength, reaching 72.01 MPa. Computational simulations, performed using ANSYS software, corroborate experimental findings, demonstrating promising correlations between experimental and computational results. Moreover, the study explores the implications of print orientation on mechanical properties and offers insights into parameter optimization for enhancing mechanical performance in additive manufacturing. This research contributes to advancing the understanding of additive manufacturing processes and provides practical guidance for optimizing tensile strength in SLA 3D printing applications. Additionally, finite element analysis (FEA) predicts a maximum stress of 71.97 MPa under a tension load of 686 N, further validating the experimental and computational findings.

Finite Element Analysis of Slope Stability of Fushun West Open-Pit Mine

Finite Element Analysis of Slope Stability of Fushun West Open-Pit Mine