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finite element model and experimental validation of a solitary wave-based tonometer

JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS 2025年 168卷 107000页

作者： Hodgson, Madison Komaie, Ali Rizzo, Piervincenzo Dickerson, Samuel J. Univ Pittsburgh Dept Elect & Comp Engn 3700 OHara St1132 Benedum Hall Pittsburgh PA 15261 USA Univ Pittsburgh Dept Civil & Environm Engn 3700 OHara St724 Benedum Hall Pittsburgh PA 15261 USA Univ Pittsburgh Dept Civil & Environm Engn 3700 OHara St729 Benedum Hall Pittsburgh PA 15261 USA Univ Pittsburgh Dept Elect & Comp Engn 3700 OHara St1138 Benedum Hall Pittsburgh PA 15261 USA

Glaucoma is an age-related incurable disease and the second cause of blindness in the world. The risk of developing glaucoma increases in the presence of elevated intraocular pressure (IOP), a risk factor that can be modified through surgery. In clinical practice, IOP remains the cornerstone of the diagnosis and management of glaucoma, and Goldmann applanation tonometry (GAT) is considered the gold standard in IOP measurements. However, GAT, as any other commercial system, provides a single value that is unable to frame the circadian rhythm and sporadic surges of IOP. This capability is only possible with a portable device that patients can eventually self-administer anytime anywhere. To serve the purpose, the device must be easy-to-use and not requiring sterilization or topical anesthesia. Additional desirable features are low price and adaptability to patient's eyeball geometry. To address these needs, our group has conceptualized, assembled, and tested a new tonometer based on highly nonlinear solitary waves propagating along a chain of particles, the last of which is in dry contact with the eye to be evaluated. The hypothesis is that the travel time of the waves propagating within the chain is monotonically associated with the IOP. In this study, the effect of central corneal thickness (CCT) and IOP of artificial corneas made of polydimethylsiloxane was quantified experimentally, and modeled numerically using static and dynamic finite element analyses. The numerical and experimental results agreed in identifying a correlation between ToF and IOP and CCT. However, some quantitative discrepancies between numerical and experimental results warrant the improvement of the model.

关键词： finite element model Highly nonlinear solitary waves Intraocular pressure Tonometry

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Crash performance of a novel movable assembled barriers for expressway work zone: finite element model and full-scale collision test

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ENGINEERING STRUCTURES 2025年 333卷

作者： Meng, Yunwei Chen, Zhuochu Wang, Zixiao Liu, Zhongshuai Qing, Guangyan Zhang, Yin Qiao, Jun Liao, Hongling Chongqing Jiaotong Univ Intelligent Integrated Traff Key Lab Chongqing Chongqing 400074 Peoples R China Chongqing Jiaotong Univ Sch Civil Engn Chongqing 400074 Peoples R China China Merchants Chongqing Commun Technol Res & Des Chongqing 400067 Peoples R China China Merchants Roadway Informat Technol Chongqing Chongqing 400067 Peoples R China China Railway Siyuan Survey & Design Grp Co Ltd Wuhan 430063 Peoples R China Shenzhen Sunzedo Highway Engn Co Ltd Shenzhen 518000 Peoples R China

When carrying out construction on an expressway during operation period, the safety of personnel and equipment in the work zone is critical. There is an urgent need to develop barrier facilities that are suitable for work zone, provide protective capabilities, and have appropriate deformation. A novel barrier system, designated as the movable assembled barrier (MAB), has been introduced, offering the advantage of not necessitating anchoring to the pavement. The upper part consists of steel components, while the lower part is a reinforced concrete base. The barrier's resistance to vehicle impact is derived from the friction force between the base and the pavement. A finite element model, in conjunction with long short-term memory (LSTM) networks and genetic algorithms, was employed to optimize two critical structural parameters of the barrier: the friction coefficient between the barrier and the pavement, and the height of the barrier. This optimization was based on a dataset comprising maximum lift height of the gravity center, roll angle of vehicle and lateral displacement values of the barrier. In accordance with MASH testing requirements, the optimized barrier structure underwent numerical simulations to evaluate its crash performance, with results compared to full-scale crash tests. The research indicates that the MAB structure generates lower ASI values and roll angles during vehicle impacts. Additionally, the lateral displacement values of MAB are minimized, demonstrating good guiding performance for vehicles. Overall, the novel barrier meets the safety standards of MASH TL-4. This innovative barrier structure contributes to ensuring safety in expressway work zone.

关键词： Crash performance Movable assembled barrier Expressway work zone Friction Height of barrier finite element model Full-scale crash test

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Key conditional quotient of random finite element model under measurement conditions

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2025年 440卷

作者： Zhao, Yuelin Wu, Feng Dalian Univ Technol Sch Mech & Aerosp Engn State Key Lab Struct Anal Optimizat & CAE Software Ind Equipment Dalian 116024 Peoples R China

Uncertainty and nonlinearity in real-world structures like complex connections and composite materials often impede the establishment of accurate finite element models, requiring measurement assistance to estimate the actual structural response. However, accurately and efficiently estimating the structural response in the face of random measurement errors, structural uncertainty, and nonlinear effects remains a challenge. In this study, a novel key conditional quotient (KCQ) theory has been presented to tackle this challenge. By extracting key conditions from measurement data and applying the principle of probability conservation, the KCQ theory provides an precise quotient-form expression, i.e., KCQ, for estimating the structural response considering random measurement errors, structural uncertainty, and nonlinearity. To effectively extract key measurement conditions, this study also proposes two innovative methods: the strong correlation measurement points method, and the covariance matrix of measurement errors method. To accurately and efficiently estimating the KCQ, a numerical method by combining the generalized quasi-Monte Carlo method based on the generalized center discrepancy and an offline-online coupling computational strategy is proposed. Five numerical examples are provided to verify the precision, efficiency, and robustness against measurement errors of the proposed KCQ theory and numerical method.

关键词： finite element model Measurement data Response estimation Random field Key conditional quotient Generalized quasi-Monte Carlo

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Development of a Detailed finite element model of the BIPED MK2 and Verification of Fidelity in Two Cases of Blunt Impact

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ANNALS OF BIOMEDICAL ENGINEERING 2025年第5期53卷 1226-1246页

作者： Chauvet, Robert Martin, Ashton Rovt, Jennifer Petel, Oren Ouellet, Simon Westover, Lindsey Dennison, Christopher R. Univ Alberta Dept Mech Engn 116 St & 85 Ave Edmonton AB T6G 2R3 Canada Carleton Univ Dept Mech & Aerosp Engn 1125 Colonel Dr Ottawa ON K1S 5B6 Canada Def Res & Dev Canada Valcartier Res Ctr 2459 Bravoure Rd Quebec City PQ G3J 1X5 Canada Univ Alberta Dept Biomed Engn 116 St & 85 Ave Edmonton AB T6G 2R3 Canada Univ Alberta Dept Mech Engn Biomed Instrumentat Lab Edmonton AB Canada Univ Victoria Dept Mech Engn Biomech & Instrumentat Lab 3800 Finnerty Rd Victoria BC V8P 5C2 Canada

Physical surrogates of the human head are commonly used to model cranial impacts, assess helmet efficacy and assess likelihood of head injuries. The Brain Injury Protection Evaluation Device (BIPED mk2) is a head form that contains a brain simulant, cerebrospinal fluid layer (CSF), connective membranes, a skull and a skin layer, and can be configured to measure kinematics, pressures and strains. In design efforts to increase the biofidelity of surrogates, finite element models play a significant role in assessing design iterations that better mimic the biological response of the head during impact. This study aims to create a digital model of the BIPED mk2 and provide a robust comparison to experimental pressure and strain data, measured from specific impact scenarios. Kinematics from two separate frontal impact experiment campaigns were used to drive the BIPED mk2 finite element model. In the first experiments, brain pressure was extracted from in situ transducers. In the second, brain strain was extracted from post hoc imagery analysis. These pressure and strain data are the basis on which we verify the pressures and strains reported from the finite element model. Pressure and displacement time series responses were compared with experimental data using a CORrelation Analysis (CORA). The average CORA rating for pressure measurements taken at the front brain sensor was 0.701 using the kinematic model inputs and 0.851 for the force model inputs. For the rear brain sensor, the signals were deemed poor fits as the average CORA scores were 0.442 for the kinematic input and 0.255 for the force input. CORA ratings for the comparison of displacement data in the x (anterior-posterior) and z (superior-inferior) directions of the 18 nodes tested resulted in a range of values from 0.012 to 0.936. The results matched best in the interior but were poor along the perimeter of the brain depending on the location of the point in relation to the brain surface. We speculate the mixe

关键词： Concussion Brain trauma Surrogate model finite element model Impact

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Discussion on AC Resistance and Temperature of ACSR Based on finite element model Assistance

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ENERGIES 2025年第3期18卷

作者： Yu, Jianbo Wu, Changqing Huang, Hao Xie, Dexin Qin, Feixiang Jiang, Jian He, Gaohui State Grid Chongqing Elect Power Co Econ & Technol Res Inst Chongqing 401121 Peoples R China State Grid Chongqing Elect Power Co Chongqing 400015 Peoples R China Southwest Univ Coll Engn & Technol Chongqing 400715 Peoples R China

In overhead wire transmission systems, the presence of AC resistance results in increased energy dissipation, adversely affecting the lines' capacity to conduct current. This paper employs a finite element aluminum conductor steel-reinforced (ACSR) model, combined with electrical measurement techniques, to investigate AC resistance. By applying varying levels of AC current, the model is employed to determine the AC resistance which closely aligns with theoretical values estimated using the Morgan algorithm. The trends observed in the parameters are consistent, thereby validating the accuracy of the model. Following simulations and analyses regarding both AC resistance and temperature variations within the conductors-and incorporating empirical measurement results-it is demonstrated that, when environmental factors are not considered, any increase in the conductor temperature can be integrated into a revised model. This updated model is subsequently compared against test results obtained from an experimental platform;the findings confirm that the estimation errors remain within an acceptable range. Overall, this simulation model serves as a valuable reference for assessing AC losses in existing conductors, as well as contributing to reduced experimental costs while mitigating the associated risks and challenges. In summary, this simulation model serves as an essential reference for assessing AC losses in current conductors and aids in reducing experimental costs while addressing the associated risks and challenges.

关键词： ACSR AC resistance finite element model energy saving conductor

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Thermal stress analysis of half-Heusler thermoelectric module by 3D finite element model and orthogonal tests

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JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T 2025年 36卷 2422-2429页

作者： Zhang, Pengxin Lu, Yanyan Song, Qingfeng Wang, Chao Zou, Peng Chen, Lidong Wang, Wenzhi Bai, Shengqiang Chinese Acad Sci Shanghai Inst Ceram State Key Lab High Performance Ceram & Superfine M Shanghai 200050 Peoples R China Univ Chinese Acad Sci Ctr Mat Sci & Optoelect Engn Beijing 100049 Peoples R China Northwestern Polytech Univ Sch Aeronaut Xian 710072 Shanxi Peoples R China Aircraft Strength Res Inst China Natl Key Lab Strength & Struct Integr Xian 710065 Shaanxi Peoples R China

Irrational structural design and mismatch of material mechanical properties cause thermal stress in thermoelectric (TE) devices, which leads to performance degradation and device failure. Previous researches mainly focus on the independent impact of specific structural parameters, while the influence of material mechanical properties and coupling of multiple factors are often overlooked. In this study, a 3D finite element model was built by Abaqus to study the thermo-mechanical performance of TE devices, in which the temperature dependent material properties were considered. Through orthogonal tests, the effect of structural parameters and material properties, and their coupled impact on thermal stress were investigated. The trend and significance of the effect for these factors were obtained, and the optimized structure and material options were proposed. The variance analysis shows that the thickness of barrier layers and electrodes are most crucial among all structural parameters, while the yield strength of barrier layers, the coefficient of thermal expansion of ceramics have the most significant influence on stress among the all material properties. Moreover, the couplings between these factors cannot be ignored. Taking the ultimate strength as standard, the optimal model we proposed increase the mechanically safety operating temperature of the device from 500 K to 900 K, which provides effective guidance for thermal stress reducing and service reliability improvement of TE devices.

关键词： Thermoelectric module Thermal stress finite element model Orthogonal tests

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Robustness analysis of multi-layer feedforward artificial neural networks for finite element model updating

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APPLIED SOFT COMPUTING 2025年 171卷

作者： Mehrkash, Milad Santini-Bell, Erin Univ New Hampshire Dept Civil & Environm Engn Durham NH 03824 USA

finite element model updating requires a computational solution procedure for minimizing the errors between the responses of an actual structure and the predictions of its numerical model. Modal data have shown great potential to be used as the inputs of neural networks for model updating;however, the neural network robustness depends on the combination of modal data and the network architecture selection. This paper discusses the neural network methodology for updating models and highlights the critical points for incorporating modal data as the parameters determining the network architecture. Several arrangements are examined for the input layer of networks that employ multi-layer perceptron and radial basis functions for estimating the structural parameters of a cantilever beam and a benchmark structural grid. The modal outputs of the analytical models feed the input layer of the neural networks to estimate the elemental stiffness and mass parameters. Noise-free and noisecontaminated simulated modal data are used to verify the noise resistance of the network architectures. Full factorial and Latin hypercube techniques are exploited for sampling the training data. The results indicate that including mode shape information of the lowest modes in the input layer could improve the parameter estimation accuracy more than considering natural frequencies of the higher modes. Also, the estimation procedure shows negligible sensitivity to the sparsity of input samples in the full factorial method, which can alleviate its computational intensity. Further, the radial basis function neural networks can decrease the training time without loss of estimation accuracy, while their noise-resistance is comparable with that of the multi-layer perceptron networks. The presented methodology simplifies the neural network's topological aspects to selecting the number of hidden neurons, reducing subjective complexity. Hence, judiciously selecting the number of hidden neurons to prevent

关键词： model updating Neural network Modal data finite element model Network topology

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Investigation on Optimization of finite element model for Stress Analysis of 12Cr1MoV Main Steam Pipeline Elbow

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CRYSTALS 2025年第3期15卷

作者： Wang, Shutao Shi, Renqiang Wu, Jian Yang, Chao Liu, Huan Jiangsu Frontier Elect Power Technol Co Ltd Nanjing 211100 Peoples R China Hohai Univ Coll Mat Sci & Engn Changzhou 213200 Peoples R China

Stress analysis is of great significance for components in thermal power plants, and an inaccurate model could cause inaccuracy in the life assessment of the plant. During the manufacturing process of elbows, issues such as cross-sectional elliptical deformation and uneven wall thickness frequently occur. However, existing studies have not thoroughly investigated these phenomena. In this study, a modified finite element model based on the dimension of an actual elbow was established for stress analysis and compared with that of the ideal uniform model. Subsequently, microstructure characterization and mechanical property tests were conducted on the elbow to validate both models. The stress concentration area in the corrected model has shifted from the inner arc region of the ideal model to the inner wall of the neutral plane region. Both optical microscopy and SEM results indicate that microstructural degradation in the neutral plane region is more pronounced, characterized by non-uniform grains, coarse carbides, and creep cavities. The hardness values of the inner wall in the neutral plane area are significantly lower than that in the inner arc area, and the tensile sample in the neutral plane area fractures rapidly after yielding, exhibiting poorer toughness compared to the samples in the inner arc area. Moreover, the creep resistance in the neutral plane area is much lower than that in the inner arc area. By integrating finite element simulation with experimental validation, the accuracy of the corrected finite element model presented in this paper has been confirmed, providing valuable theoretical and experimental guidance for the life assessment of elbows in thermal power plants.

关键词： main steam pipeline elbow finite element model microstructure creep

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Simplified finite element model for screwed connections with clip angle

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STRUCTURES 2025年 74卷

作者： Zhou, Jingsheng Thai, Huu-Tai Ngo, Tuan Bldg 4-0 CRC Caulfield Vic Australia Univ Melbourne Dept Infrastruct Engn Melbourne Australia

This study investigates the response of cold-formed steel screwed connection with clip angle under either tension or shear through finite element (FE) analysis. A simplified FE model is proposed to predict the full-range behaviour of connections. In the proposed FE model, the sheet material and screw head/washer are modelled by shell elements, while one set of three connector elements is used to model one transferred load (either tension or shear) between two structural elements. The connector element set consists of two Cartesian-type connector elements and one Axial-type connector element, isolating and representing the transferred load, respectively. For the Axial-type connector element, a bi-linear force-deformation curve is derived, including the initial stiffness, ultimate resistance, and ultimate deformation capacity. By assembling all connector elements into the FE model, the non-linear full-range force-deformation response of the connection is predicted. The proposed model is validated by using the experimental results collected from literatures, including 24 connections in tension and 6 connections in shear. The parametric studies are further conducted to investigate the effects of connection geometries on the ultimate resistance and ductility of connections, including three failure modes, i.e. pull-out, screw in shear, and clip angle buckling.

关键词： finite element model Cold-formed steel Full-range behaviour Connection with clip angle

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Mechanobiochemical finite element model to analyze impact-loading-induced cell damage, subsequent proteoglycan loss, and anti-oxidative treatment effects in articular cartilage

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BIOMECHANICS AND modelING IN MECHANOBIOLOGY 2025年 1-16页

作者： Kosonen, Joonas P. Eskelinen, Atte S. A. Orozco, Gustavo A. Coleman, Mitchell C. Goetz, Jessica E. Anderson, Donald D. Grodzinsky, Alan J. Tanska, Petri Korhonen, Rami K. Univ Eastern Finland Dept Tech Phys Kuopio Finland Univ Iowa Dept Orthoped & Rehabil Iowa IA USA Univ Iowa Dept Biomed Engn Iowa LA USA MIT Dept Biol Engn Cambridge MA USA MIT Dept Elect Engn & Comp Sci Cambridge MA USA MIT Dept Mech Engn Cambridge MA USA

Joint trauma often leads to articular cartilage degeneration and post-traumatic osteoarthritis (PTOA). Pivotal determinants include trauma-induced excessive tissue strains that damage cartilage cells. As a downstream effect, these damaged cells can trigger cartilage degeneration via oxidative stress, cell death, and proteolytic tissue degeneration. N-acetylcysteine (NAC) has emerged as an antioxidant capable of inhibiting oxidative stress, cell death, and cartilage degeneration post-impact. However, the temporal effects of NAC are not fully understood and remain difficult to assess solely by physical experiments. Thus, we developed a computational finite element analysis framework to simulate a drop-tower impact of cartilage in Abaqus, and subsequent oxidative stress-related cell damage, and NAC treatment upon cartilage proteoglycan content in Comsol Multiphysics, based on prior ex vivo experiments. model results provide evidence that immediate NAC treatment can reduce proteoglycan loss by mitigating oxidative stress, cell death (improved proteoglycan biosynthesis), and enzymatic proteoglycan depletion. Our simulations also indicate that delayed NAC treatment may not inhibit cartilage proteoglycan loss despite reduced cell death after impact. These results enhance understanding of the temporal effects of impact-related cell damage and treatment that are critical for the development of effective treatments for PTOA. In the future, our modeling framework could increase understanding of time-dependent mechanisms of oxidative stress and downstream effects in injured cartilage and aid in developing better treatments to mitigate PTOA progression.

关键词： Post-traumatic osteoarthritis Cell death Oxidative stress Proteoglycan Anti-oxidative treatment finite element model

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