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Recently, Egypt had seismic activity. These seismic events have affected the stability of minarets, especially historical ones. Weight is one of the minaret's main stability factors. The main objective of the current research is to perform a three-dimensional (3D) assessment of an existing minaret, determine its accurate spatial model, document its current condition, examine its stability in the event of earthquakes, and identify the requisite measures to safeguard the minaret from any potential damage. The masonry to construct the minaret was used by extracting and examining specimens of this substance to determine its physical characteristics. The current work created three-dimensional models of the Abou-Ghanam El-Bialy minaret using a terrestrial laser scanner (TLS) to document its current condition, as well as minaret was subjected to a free vibration analysis using 3D finite element modeling. Finally, the minaret's seismic behavior was assessed utilizing mode forms, base responses, and normal stresses. The surveying method effectively documented the Minarets' existing case. The 3D seismic analysis showed that the minaret responded dynamically to earthquake loading, with mode shapes, base reactions, and normal stresses being crucial characteristics. Based on these data, we may suggest procedures to protect the minaret during seismic events. [ABSTRACT FROM AUTHOR]

By addressing the phenomenon of carbody abnormal vibrations in the field, the acceleration of the carbody and bogie was measured using accelerometers, and the diamond mode of the carbody was identified. The equivalent conicity of the wheelset and the acceleration at the frame end indicated that the shaking of the carbody was caused by bogie hunting. In the SIMPACK simulation, the acceleration frequency and amplitude at the frame end and midsection of the side beam were calculated. The lateral deformation amplitude of the side beam in the finite element model was extracted, and a modal shape function for the diamond-shaped mode was established. By utilizing the modal vibration equation, the modal generalized forces of the carbody were computed, revealing that, during carbody shaking, the yaw damper force contributed significantly among the forces of the secondary suspension, with the phase difference between the front and rear bogies approaching 180°. This insight offers a novel perspective for subsequent active control strategies. Subsequently, these modal generalized forces were applied as external excitation to a coupled vibration model encompassing both the carbody and transformer. Aiming to reduce the acceleration amplitude at the side beam, the transformer was treated as a dynamic vibration absorber, allowing for the optimization of its lateral suspension parameters. As a result, the lateral and vertical acceleration amplitudes at the side beam were concurrently reduced, with the maximum decrease reaching 58.5%, significantly enhancing the ride comfort. [ABSTRACT FROM AUTHOR]

Living organisms are constructed from proteins that assemble into biomolecular complexes, each with a unique shape and function. Our knowledge about the structure–activity relationship of these complexes is still limited, mainly because of their small size, complex structure, fast processes, and changing environment. Furthermore, the constraints of current microscopic tools and the difficulty in applying molecular dynamic simulations to capture the dynamic response of biomolecular complexes and long-term phenomena call for new supplementary tools and approaches that can help bridge this gap. In this paper, we present an approach to comparing biomolecular and origami hierarchical structures and apply it to comparing bacterial microcompartments (BMCs) with spiral-based origami models. Our first analysis compares proteins that assemble the BMC with an origami model called "flasher", which is the unit cell of an assembled origami model. Then, the BMC structure is compared with the assembled origami model and based on the similarity, a physical scaled-up origami model, which is analogous to the BMC, is constructed. The origami model is translated into a computer-aided design model and manufactured via 3D-printing technology. Finite element analysis and physical experiments of the origami model and 3D-printed parts reveal trends in the mechanical response of the icosahedron, which is constructed from tiled-chiral elements. The chiral elements rotate as the icosahedron expands and we deduce that it allows the BMC to open gates for transmembrane passage of materials. [ABSTRACT FROM AUTHOR]

Introduction: Targeted herbicide application refers to precise application of herbicides in weed-infested areas according to the location and density of farmland weeds. At present, targeted herbicide application in wheat fields generally faces problems including the low herbicide adhesion rate, leading to omission and excessive loss of herbicides. Methods: To solve these problems, changes in the impact force of herbicide and the weed leaves in the operation process of a spraying system were studied from the interaction between weeds and herbicides applied. A dynamic model of weed leaves was established. On this basis, the research indicated that the herbicide adhesion rate is highest under spraying pressure of 0.4 MPa and flow rate of 0.011 kg/s when the spray height is 300 mm. To study the dynamic deformation of weed leaves and the distribution of liquid herbicides in the external flow field under weed-herbicide interaction, a dynamic simulation model of herbicide application was built using the finite element method. Results and Discussion: The results show that when the spray height is 300 mm, the maximum weed leaf deformation index (LDI) is 0.43 and the velocity in the external flow field is 0 m/s under spraying pressure of 0.4 MPa and flow rate of 0.011 kg/s. This finding indicates that the herbicide is not splashed elsewhere and the turbulence intensity in the weed area is 2%, implying steady flow of the herbicide, most of which can be retained on weed leaves. Field test results of application quality of the herbicide show that the maximum LDI is 0.41 and the coverage of the herbicide in the sheltered area below the leaves is 19.02% when the spraying pressure is 0.4 MPa, flow rate is 0.011 kg/s, and spray height is 300 mm. This solves the problem of a low rate of utilization of herbicides because the herbicide passes through weed plants, and achieves the precision herbicide application in wheat fields. [ABSTRACT FROM AUTHOR]

Abnormal wear of stitch wires due to interference poses a serious threat to railway safety. To avoid this scenario, the concept of the dynamic envelope of the stitch wire was proposed, accompanied by an interference check method. A multi-node beam model of the stitch wire was established using the finite element method, employed to simulate the pantograph and catenary system, and validated by field test. The dynamic behaviour of the stitch wire was studied, and the concept of dynamic envelope was introduced. Moreover, factors affecting this envelope were analysed, and an interference check method was proposed. Results demonstrate that, the vibration of the stitch wire mainly occurs in the vertical direction and intensifies with increasing speed. Its vertical vibration increases from 70 mm to 137 mm as the train speed goes from 300 km/h to 400 km/h. Cantilever assembly errors and dropper installation issues are the main causes for the abnormal wear of stitch wires. A 100 mm assembly error reduces the clearance from 67 mm to 14 mm, while a 2 m dropper installation error eliminates the clearance entirely. This study provides valuable insights for enhancing the safety of catenary system. [ABSTRACT FROM AUTHOR]

This study focuses on the structural integrity analyses of a submersible cage with dimensions of 20 m in diameter and 10 m depth under extreme oceanographic conditions, including current speed of 0.5 and 1 m/s, combined with waves ranging from 2 to 5 m in height and a period of 7 s. Employing a dynamic simulation model based on finite elements, The study examines the stresses in the cage's pipes, as well as the tension in the bridle lines and mooring lines. Results indicate that submerging the cage leads to a reduction in peak tensions, with mooring lines experiencing a decrease of up to 32% and bridle lines experiencing a decrease of up to 59%. Furthermore, the stresses in the pipes exhibit a significant decline of up to 71.4%. These findings demonstrate that the submersible cage, when submerged, significantly reduces peak stresses, thereby decreasing the risk of structural loss or damage when the system is submerged. [ABSTRACT FROM AUTHOR]

Globally, rail transit is developing toward higher speeds, larger axle weights, and greater environmental friendliness. The more and more complex wheel–rail interaction will result in the dynamic responses of vehicles, tracks and other structures needing more in-depth theoretical research. However, most existing models for dynamic simulations of the vehicle–track coupling system need to extend the model on both sides of the concerned region to eliminate the boundary effect. To a certain extent, this kind of process method increases the computational effort. To overcome this disadvantage, a hybrid model combined with the analytical method and finite element method was proposed. The moving support system (including transition nodes) was specially established referring to the analytical solution of rail deflection based on the Winkler elastic foundation beam theory to realize the combination of the two methods. Two examples were presented to verify the stability and accuracy of the proposed model. The comparison results show that simulation results of vertical wheel–rail forces and track vibrations are almost consistent with the existing model. Furthermore, the calculation efficiency was discussed and certificated under different long-marshalling trains, with an obvious speedup factor that could be more than 2.5 for 16-marshalling train. The proposed model has a wide application prospect in the vehicle–track coupling analysis of long-marshalling trains, especially for heavy haul railways with hundreds of vehicles. [ABSTRACT FROM AUTHOR]

This study developed a finite element method (FEM) dynamic simulation to visualize the deployment behavior of thin membrane structures in the space environment. The proliferation of space debris resulting from accelerated space development threatens the future of space. Numerous researchers have explored strategies to prevent artificial structures from remaining in space and becoming space debris. One such method involves utilizing a drag sail device to de-orbit artificial structures, which reduces their kinetic energy by inducing additional atmospheric drag, allowing them to re-enter the Earth's atmosphere. Tohoku University and Nakashimada Engineering Works, Ltd. have successfully developed a deployable membrane structure for de-orbit purposes and demonstrated its effectiveness in space. Space structures, such as membranes, exhibit highly nonlinear behavior due to their flexible properties, and ground tests by actual devices cannot fully demonstrate their deployment stability in a microgravity environment. Therefore, evaluating the deployment behavior using simulation methods instead of relying solely on hardware development is crucial. In this study, we employed FEM to establish a simulation environment, which enables us to consider nonlinear oscillations of flexible structures, such as the membrane. The simulation results closely reproduce the deployment motion observed in ground tests by appropriately incorporating constraint conditions related to deployment forces and hardware interactions, such as a hub component initially wrapped by the membrane. The simulation facilitated an assessment of the impact of membrane properties on deployment without the need for physically developing an actual hardware device. We proposed evaluation methods for determining membrane properties in terms of the trend of propagation of deployed surface area and the tendency of deployment motion. This established simulation technique can be utilized to develop future flexible space structures. • De-orbit Membrane Mechanism (DOM) was developed as a satellite de-orbit application. • Formulate nonlinear FEM analysis of non-spin type deployable structures. • Modeling techniques of the membrane in simulation. • Evaluation of the membrane deployment between simulation and ground experiments. • Proposed methods can be used to predict the deployment behavior of the actual membrane. [ABSTRACT FROM AUTHOR]

This paper presents a numerical study on the dynamic response and impact mitigation capabilities of layered ceramic–polymer–metal (CPM) composites under plate impact loading, focusing on the layer sequence effect. The layered structure, comprising a ceramic for hardness and thermal resistance, a polymer for energy absorption, and a metal for strength and ductility, is analyzed to evaluate its effectiveness in mitigating the impact loading. The simulations employed the VUMAT subroutine of DSGZ material models within Abaqus/Explicit to accurately represent the mechanical behavior of the polymeric materials in the composites. The VUMAT implementation incorporates the explicit time integration scheme and the implicit radial return mapping algorithm. A safe-version Newton–Raphson method is applied for numerically solving the differential equations of the J 2 plastic flow theory. Analysis of the simulation results reveals that specific layer configurations significantly influence wave propagation, leading to variations in energy absorption and stress distribution within the material. Notably, certain layer sequences, such as P-C-M and C-P-M, exhibit enhanced impact mitigation with a superior ability to dissipate and redirect the impact energy. This phenomenon is tied to the interactions between the material properties of the ceramic, polymer, and metal, emphasizing the necessity of precise material characterization and enhanced understanding of the layer sequencing effect for optimizing composite designs for impact mitigation. The integration of empirical data with simulation methods provides a comprehensive framework for optimizing composite designs in high-impact scenarios. In the general fields of materials science and impact engineering, the current research offers some guidance for practical applications, underscoring the need for detailed simulations to capture the high-strain-rate dynamic responses of multilayered composites. [ABSTRACT FROM AUTHOR]

Temporal bone is often hit by projectiles. Temporal gunshot wounds must be deeply evaluated to establish wound morphology and stress distribution. Finite element analysis (FEA) is a promising tool that can support forensic aspects. A three-dimensional finite element model of a dry skull filled with neural soft tissue and a projectile.40 calibre S&W were obtained. Two situations were simulated: shot angle fired at 90° with and without neural soft tissue. The results exhibit different morphologies in bony entrance wounds as well as the strong influence of soft tissue. There was good reproducibility between bone and neural tissue real behaviour, and the finite element model that was built. In conclusion, the presence of neural soft tissue cannot be neglected in gunshot wounds, since it does alter results. [ABSTRACT FROM AUTHOR]

To study the dynamic mechanical properties and failure characteristics of intersecting jointed rock masses with different joint distributions under confining pressure, considering the cross angle α and joint persistence ratio η, a numerical model of the biaxial Hopkinson bar test system was established using the finite element method–discrete-element model coupling method. The validity of the model was verified by comparing and analyzing it in conjunction with laboratory test results. Dynamics-static combined impact tests were conducted on specimens under various conditions to investigate the strength characteristics and patterns of crack initiation and expansion. The study revealed the predominant factors influencing intersecting joints with different angles and penetrations under impact loading. The results show that the peak stress of the specimens decreases first and then increases with the increase of the cross angle. When α < 60°, regardless of the value of η, the dynamic stress of the specimens is controlled by the main joint. When α ≥ 60°, the peak stress borne by the specimens decreases with increasing η. When α < 60°, the initiation and propagation of cracks in the cross-jointed specimens are mainly controlled by the main joint, and the final failure surface of the specimens is composed of the main joint and wing cracks. When α ≥ 60° or η ≥ 0.67, the secondary joint guides the expansion of the wing cracks, and multiple failure surfaces composed of main and secondary joints, wing cracks, and co-planar cracks are formed. Increasing lateral confinement significantly increases the dynamic peak stress able to be borne by the specimens. Under triaxial conditions, the degree of failure of the intersecting jointed specimens is much lower than that under uniaxial and biaxial conditions. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the design and optimization of landing gear buffers to improve the landing-phase comfort of civil aircraft. Design/methodology/approach: The vibration comfort during the landing and taxiing phases is calculated and evaluated based on the flight-testing data for a type of civil aircraft. The calculation and evaluation are under the guidance of the vibration comfort standard of GB/T13441.1-2007 and related files. The authors establish here a rigid-flexible coupled multibody dynamics finite element model of one full-size aircraft. Furthermore, the authors also implement a dynamic simulation for the landing and taxiing processes. Also, an analysis of how the main parameters of the buffers affect the vibration comfort is presented. Finally, the optimization of the single-chamber and double-chamber buffers in the landing gear is performed considering vibration comfort. Findings: The double-chamber buffer with optimized parameters in landing gear can improve the vibration comfort of the aircraft during the landing and taxiing phases. Moreover, the comfort index can be increased by 25.6% more than that of a single-chamber type. Originality/value: To the best of the authors' knowledge, this study first investigates the evaluation methods and evaluation indexes on the aircraft vibration comfort, then further conducts the optimization of the parameters of landing gear buffer with different structures, so as to improve the comfort of aircraft passengers during landing process. Most of the current studies on aircraft landing gear have focused on the strength and safety of the landing gear, with very limited research on cabin vibration comfort during landing and subsequent taxiing because of the coupling of runway surface unevenness and airframe vibration. [ABSTRACT FROM AUTHOR]

Owing to the challenge of capturing the dynamic behaviour of metal experimentally, high-precision numerical simulations have become essential for analysing dynamic characteristics. In this study, calculation accuracy was improved by analysing the impact of constitutive models using the finite element (FE) model, and the deep learning (DL) model was employed for result analysis. The results showed that FE simulations with these models effectively capture the elastic-plastic response, and the ZA model exhibits the highest accuracy, with a 26.0% accuracy improvement compared with other models at 502 m/s for Hugoniot elastic limit (HEL) stress. The different constitutive models offer diverse descriptions of stress during the elastic-plastic response because of temperature effects. Concurrently, the parameters related to the yield strength at quasi-static influence the propagation speed of elastic waves. Calculation show that the yield strength at quasi-static of 6061 Al adheres to y = ax + b for HEL stress. The R-squared (R2) and mean absolute error (MAE) values of the DL model for HEL stress predictions are 0.998 and 0.0062, respectively. This research provides a reference for selecting constitutive models for simulation under the same conditions. [ABSTRACT FROM AUTHOR]

This paper's scope is to develop an intelligible Finite Element Analysis (FEA) method, utilized to determine and quantify the assembly forces required to assemble the snap-fit component, which is made of a glass fiber reinforced polyamide (type 6, 60% glass fiber, PA6 GF50), as well as to determine the snap-fit joint maximum retention forces. The proposed FEA method is to be used in Abaqus as a standard solver type, considering its operation ease and simplicity in creating the model. The setback of implementing the standard solver approach is that during the snap-fit assembly, at a certain point in the simulation, the behavior is transformed from a static movement to a dynamic one, precisely when the snap moves backward in the assembled position, at this point, due to the dynamic behavior of the simulation, the solution will continue to diverge, and the convergence is not achieved. [ABSTRACT FROM AUTHOR]

Time-domain or transient dynamic response method is the most traditional method used to evaluate the dynamic response of a vibratory system subjected to deterministic inputs. The inertia or damping effects are very crucial in the time scale of loading. The present work determines the time domain analysis of railway locomotive using finite element analysis for Indian tracks. The track inputs are modelled as an ellipsoidal bump, and variations in displacement at different key locations of the truck and carbody models are plotted subjected to standard loading conditions. The response plot of the front and rear locations of the locomotive truck and carbody indicate that these regions are more responsive to wheel inputs in comparison to the mid portion due to unbalanced mass distribution. In the further study vertical-lateral random inputs are measured through track recording car and modelled to express in the form of PSD. These random inputs are provided to finite element modelled flexible bogie frame, and acceleration response is determined. The results obtained are compared with the same obtained from rigid bogie frame formulated using an analytical model. The results obtained from the flexible and rigid body models are found to be in good agreement. [ABSTRACT FROM AUTHOR]

Background: While the development of CT imaging technique has brought cognition of in vivo organs, the resolution of CT images and their static characteristics have gradually become barriers of microscopic tissue research. Purpose: Previous research used the finite element method to study the airflow and gas exchange in the alveolus and acinar to show the fate of inhaled aerosols and studied the diffusive, convective, and sedimentation mechanisms. Our study combines these techniques with CT scan simulation to study the mechanisms of respiratory movement and its imaging appearance. Methods: We use 3D fluid‐structure interaction simulation to study the movement of an ideal alveolus under regular and forced breathing situations and ill alveoli with different tissue elasticities. Additionally, we use the Monte Carlo algorithm within the OpenGATE platform to simulate the computational CT images of the dynamic process with different designated resolutions. The resolutions show the relationship between the kinematic model of the human alveolus and its imaging appearance. Results: The results show that the alveolus and the wall thickness can be seen with an image resolution smaller than 15.6 μm. With ordinary CT resolution, the alveolus is expressed with four voxels. Conclusions: This is a preliminary study concerning the imaging appearance of the dynamic alveolus model. This technique will be used to study the imaging appearance of the dynamic bronchial tree and the lung lobe models in the future. [ABSTRACT FROM AUTHOR]

Percutaneous needle insertion constitutes a widely adopted technique for performing minimally invasive operations. Robot-assisted needle placement and virtual surgical training platforms have the potential to significantly improve the accuracy of these operations. For this, the development of mathematical models that provide a complete characterization of the underlying dynamics of medical needles is considered of paramount importance. In this paper, we develop two three-dimensional nonlinear rigid/flexible dynamic models of brachytherapy and local anaesthetic transperineal biopsy (LATP) needles. The proposed models relax the assumptions of previous investigations, quantify the vibrational behaviour and the rigid-body dynamics of medical needles and allow for real-time haptic and visual feedback information. Their accuracy and computational efficiency are assessed and validated using commercial software. The results show that, among the examined methods, the Rigid Finite Element Method provides the most accurate and numerically efficient solution for capturing the dynamics of flexible medical needles. [ABSTRACT FROM AUTHOR]

This paper presents a virtual generation method for the heterogeneous microstructure of asphalt mixtures. The coarse aggregates used in the digital asphalt mixture were derived from real aggregates captured by a three-dimensional (3D) laser scanner. Then, a rigid-body dynamic simulation framework was proposed to generate a stable skeletal structure composed of coarse aggregates similar to those formed by compaction. Furthermore, FAM and air voids were generated based on the generated aggregate skeleton and the assumption of equal thickness of FAM film. To prove the reliability of the model, the air voids of the digital asphalt mixture samples were verified by comparison with real specimens. The generated digital specimens were also applied to finite element method (FEM) simulations to predict the dynamic modulus of the asphalt mixture and the simulated results were in good agreement with the experimental results. The method can be applied to study the spatial distribution of asphalt mixture components, the movement pattern of aggregate particles during compaction and numerical simulations at the microscopic scale. [ABSTRACT FROM AUTHOR]

The dual-rotor system is the core component of advanced aero-engine. Establishing a reasonable, accurate, and efficient dynamics model is the key to studying the dynamics and vibration of the rotor system for aero-engine. This manuscript takes a representative aircraft engine dual-rotor system as a prototype, considers the rig-id-flexible coupling characteristics of different stiffness elastic supports and rotor structures, and establishes an analytical dynamic model of the dual-rotor system. Based on the established dynamic model, the natural char-acteristics of the dual-rotor system are analyzed. The model was validated using two different research methods: the rigid-flexible coupling multi-body system dynamics simulation platform ADAMS, and finite element analy-sis. The dynamic model of the dual-rotor system established in this paper can meet the requirements of hierar-chical rigid-flexible coupling of system and structure, overall mass distribution, and stiffness distribution. In particular, it can also effectively realize the simulation of multi-facet and multi-phase unbalanced vibration of the rotor system. The research methods of this paper can further enrich the basic theory of dynamics and vibration of the aero-engine rotor system. [ABSTRACT FROM AUTHOR]

The finite element method is widely used to solve the problem of flexible bodies with contact-impact. To express the high-frequency and high-transient characteristics of the impact process and the high stress distribution of the local contact region, the amount of the node coordinates will be very large, which brings great burden to the dynamic simulation. It is particularly important to reduce the degrees of freedom of the system in the contact-impact problem. However, as the impact itself is a strong nonlinear problem, the linear model reduction techniques cannot be used directly. The partition method is presented to solve this problem, in which the deformation of the contact region is described by finite element node coordinates to preserve the local nonlinear characteristic while the deformation of the non-contact region is described by the reduced elastic coordinates. Different model reduction techniques including modal truncation method and Krylov subspace method are used to reduce the degrees of freedom of the non-contact region of an experimental rod-plate impact case, and the results are compared with that of the finite element method and the experiment. The simulation results show that the partition method can effectively reduce the degrees of freedom of the system and maintain good accuracy. Moreover, the Krylov subspace method has an advantage over the modal method in the model reduction of contact-impact problem. [ABSTRACT FROM AUTHOR]

This research discusses the static and dynamic analysis of the landing gear structure of an unmanned aerial vehicle (UAV). The dimensional study is conducted to investigate the effect of landing gear dimension variation on UAVs' static strength and dynamic response. Static analysis was performed with Finite Element Method (FEM) software. The dynamic response of the UAV is analyzed using a single-degree-of-freedom vibration model. Based on the static analysis results, the landing gear stiffness and strength can be increased by increasing the width and decreasing the height, radius, and length of the landing gear structure. The energy dissipation in the dynamic analysis is described by hysteresis and viscous damping model. The dynamic response simulation results show that the increase in the stiffness of the landing gear leads to an increase in force transmission and acceleration of the UAV. Furthermore, the UAV response using the viscous damping model can accurately predict the system's response with the hysteretic damping model for small damping conditions. However, the deviation was observed for large damping conditions. [ABSTRACT FROM AUTHOR]

With the development of space technology, the traditional aerospace cooling technology is hard to meet the constantly developing requirements of heat dissipation. In order to address the problem of temperature control for aerospace systems, the pump-driven fluid loop system has been often adopted. In the pump-driven fluid loop system, the rotor system is needed to be analyzed. In this paper, the rotor coupling system of the canned pump with multiple journal bearings has been studied based on the bearing data, lumped parameter method, Reynolds equation and finite element method. By solving the Reynolds equation, parameters of each bearing have been solved, and a database file has been formed. The bearing data have been addressed by linear interpolation. In this study, the static indeterminate problem has been combined to analyze the bearing force, and the bearing characteristic parameters under the steady-state condition have been solved based on the iterative method. The results indicated that the influences of clearance ratio and rotational speed on the natural frequency, critical rotational speed and unbalanced response of the rotor show certain regularity. The study provides a theoretical basis for the stable operation of the whole rotor system. [ABSTRACT FROM AUTHOR]

Consideration of standard landing cases from technical guideline document is the traditional design practice followed to ascertain aircraft landing loads. A rationale approach on landing load generation and its impact on flexible airframe dynamic response is explored, considering multi-variate landing conditions for the first time on land-base high performance aircraft. Methodology on nonlinear landing dynamic response simulation is developed by amalgamating inputs such as nonlinear nose and main landing gear dynamic models, aircraft rigid body dynamics, low speed aerodynamic and thrust forces. True representation of landing gear nonlinear oleo-pneumatic strut and tire characteristics, variable geometric strut structural stiffness and nonlinear spin-up friction resulted in satisfactory correlation of vertical and longitudinal dynamic response simulation with experimental drop test results. The adequacy of lateral dynamic model is established from the compatibility condition of landing gear and tire dynamics. A down selection methodology is worked out considering total probability and first order sensitive multi-variate landing parameters such as pitch, roll and vertical descent speed, taking into account the plausible statistical variation. Transient dynamic response simulation is then performed for the critical landing cases, on a flexible airframe finite element model by inputting landing load time history as base excitation motion. The dynamic amplification of acceleration response on flexible fuselage nose location from the simulation, is verified with flight data accelerometer frequency response. The application of flexible dynamic responses in ensuring the structural integrity of airframe is elaborated. The proposed methodology on landing load generation is pragmatic, in comparison with the traditional design practice and provides insight during early design phase thereby achieving landing gear subsystem development in-unison with airframe structural clearance aspects. [ABSTRACT FROM AUTHOR]

• A framework for a hybrid terramechanics modelling method is presented. • The method involves using ML to augment existing semi-empirical models. • Model presented in a general way that can be applied to any semi-empirical model. • Method applied to a blade simulation with the Fundamental Earthmoving Equation. • Method applied to a wheel simulation with the Bekker-Wong terramechanics formulation. The field of terramechanics focuses largely on two types of simulation approaches. First, the classical semi-empirical methods that rely on empirically determined soil parameters and equations to calculate the soil reaction forces acting on a wheel, track or tool. One major drawback to these methods is that they are only valid under steady-state conditions. The more flexible modelling approaches are discrete or finite element methods (DEM, FEM) that discretize the soil into elements. These computationally demanding approaches do away with the steady state assumption at the cost of including more model parameters that can be difficult to accurately tune. Model-free approaches in which machine learning algorithms are used to predict soil reaction forces have been explored in the past, but the use of these models comes at the cost of the valuable insight that the semi-empirical models provide. In this work, we presume that in a dynamic simulation, the soil reaction forces can be divided into a steady state component that can be captured using semi-empirical models and a dynamic component that cannot. We propose an augmented modelling approach in which a neural network is trained to predict the dynamic component of the reaction forces. We explore how this theory can be applied to the simulation of a soil-cutting blade using the Fundamental Earthmoving Equation and of a wheel driving over soft soil using the Bekker wheel-soil model. [ABSTRACT FROM AUTHOR]

With the increasing demands for railway transportation, railway networks have expanded, leading to higher operating frequencies and speeds. However, this has also, in turn, increased the technical complexity of railway transportation systems. Derailment accidents, which occur frequently and have complex outcomes, are primary concerns in such systems. Particularly, derailments cause significant damage to adjacent areas, increasing their severity compared to other railway accidents. However, a majority of research on derailment accidents has focused on preventing or simulating specific situations, whereas the analysis of post-derailment train behaviour still requires improvements. This study aimed to predict post-derailment train behaviour using finite element analysis simulations of simplified train and track models using Korea as a case study; the key factors considered were the operating speed, derailment angle, and ground friction coefficient. Various accident cases in Korea were reviewed and compared with simulated results to verify the proposed model. [ABSTRACT FROM AUTHOR]

For the pelvic fracture reduction, generally the fragment of the unaffected side is fixed and the affected side is moved to its correct anatomical position and orientation. During the pelvic fracture reduction, circumpelvic muscles deformation is closely related to the surgical accuracy. In this article, the biomechanical properties of musculoskeletal tissue during pelvic fracture reduction are studied. Five-parameter hyperelastic model named Mooney-Rivlin is adopted to analyze muscle's stress–strain relationship. The finite element model of the injured pelvic musculoskeletal tissue is established, and the deformation of circumpelvic main muscles is simulated. Then, the dynamic simulation of pelvic fracture reduction is performed according to the planned spatial reduction path. The results show that when the muscles are stretched the same stretch length, the strain of the gluteus medius is the largest. It is most prone to deformation under and the muscle injury is most easily to occur. During the pelvic fracture reduction, the strain of gluteus maximus is the largest, and it is most prone to deformation and injury. The traction length is the largest, and the traction force mainly comes from the gluteus maximus. This study provides reference for the robot assisted pelvic fracture reduction. [ABSTRACT FROM AUTHOR]

The contactless electromagnetic de-tumbling method does not have physical contact with the uncooperative space targets and can avoid generating new space debris. Due to pollution-free and high safety performance advantages, this method has a tremendous prospect in the application of de-tumbling the uncooperative space targets. In this paper, an improved arc-linear electromagnetic device and its corresponding de-tumbling method are presented based on the principle of electromagnetic eddy current, which is mainly used for the uncooperative space targets. The analytical model of the electromagnetic device is obtained by introducing the Carter and Russel-Norsworthy coefficients and validated by the finite element method (FEM). Then, the effect on the de-tumbling torque with different electromagnetic parameters is further analyzed. Finally, the three-dimensional dynamic simulation of the uncooperative space target is carried out. The results show that the uncooperative space target can be de-tumbled in a short time by the proposed contactless electromagnetic de-tumbling device. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to simulate molded printed circuit board (PCB) warpage behavior under reflow temperature distribution. Simulation models are used to estimate dynamic warpage behavior for different form factor sizes. Design/methodology/approach: This study analyzes warpage during the reflow process. The shadow moiré experiment methodology is used to collect data on the dynamic warpage performance of a model with a form factor of 10mm × 10mm × 1mm. The temperature profile with heating from 25°C to 300°C at intervals of 50°C is used, and the sample is made to undergo a cooling process until it reaches the room temperature. Subsequently, ANSYS static structural simulation is performed on similar form factor models to ascertain the accuracy of the simulation results. Findings: Results show that the deformation and total force induced by coefficient of thermal expansion (CTE) mismatch are examined based on the warpage performance of models with different sizes, that is, 45mm × 45mm × 1mm and 45mm × 15mm × 1mm. Compared with the experimental data, the simulated modeling accuracy yields a less than 5% deviation in the dynamic warpage prediction at a reflow temperature of 300°C. Results also reveal that the larger the model, the larger the warpage changes under the reflow temperature. Research limitations/implications: The simulated warpage is limited to the temperature and force induced by CTE mismatch between two materials. The form factor of the ball-grid array model is limited to only three different sizes. The model is assumed to be steady, isothermal and static. The simulation adopts homogenous materials, as it cannot accurately model nonhomogeneous multilayered composite materials. Practical implications: This study can provide engineers and researchers with a profound understanding of molded PCB warpage, minimal resource utilization and the improved product development process. Social implications: The accurate prediction of molded PCB warpage can enable efficient product development and reduce resources and production time, thereby creating a sustainable environment. Originality/value: The literature review points out that warpage in various types of PCBs was successfully examined, and that considerable efforts were exerted to investigate warpage reduction in PCB modules. However, PCB warpage studies are limited to bare PCBs. To the best of the authors' knowledge, the examination of warpage in a molded PCB designed with a molded compound cover, as depicted in Figure 3, is yet to be conducted. A molded compound provides strong lattice support for PCBs to prevent deformation during the reflow process, which is a topic of considerable interest and should be explored. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, a numerical method is proposed for a flexible tether motion that spans two different environments and has large displacement and deformation. When considering the behavior of a tethered system in which the tether cable is subjected to the above conditions, variations of an internal boundary in the tether must be considered. In general, the absolute nodal coordinate formulation (ANCF), a nonlinear finite element method, is effective for the dynamic simulation of a flexible body with large displacement and deformation. However, in conventional methods, such as ANCF, the analysis accuracy decreases and the calculation cost increases when the movement of an internal boundary across different environments is considered. In this study, an efficient numerical approach that considers the variations of an internal boundary by using ANCF using variable-domain finite elements is proposed. In addition, to further improve the calculation efficiency, dimensionless variables are introduced using appropriate representative values. The accuracy of the numerical results obtained using the proposed method, which considers an internal variable boundary, is similar to that for a conventional method. [ABSTRACT FROM AUTHOR]

This paper compares different track model formulations for the simulation of dynamic vehicle–track interaction in switches and crossings (S&C, turnouts) in a multi-body simulation (MBS) environment. The investigations are an extension of the S&C simulation Benchmark with the addition of a finite element model of a 60E1-760-1:15 turnout. This model constitutes a common reference from which four different track formulations are derived: co-running, modal superposition, finite element incorporated into the MBS model and finite element coupled to MBS using a co-simulation approach. For the different track models, the difference in modelling technique, results, simulation time, and suitability for different simulation tasks is compared. A good agreement is found between the different track model formulations for wheel–rail contact forces and rail displacements. This study found a better agreement between co-running and structural track models compared to previous studies in the prediction of wheel–rail contact forces. This appears to be due to the increased complexity of co-running track model used in this study together with a tuning of the co-running track model to the reference model in a wider frequency range. For the reader interested to reproduce the results in this paper, the reference track model is available for download. [ABSTRACT FROM AUTHOR]

Owing to the wide acceptance of fiber reinforced composites in the lightweight structure industry, the need to study its thermo‐elastic behavior in dynamical multi‐body systems still remains an open question. Standard continuum models, by virtue of first‐order gradient of deformation, cannot capture curvature effects and hence appropriate extensions of the standard modeling techniques are indispensable to model the accurate physical stiffness. The fiber‐bending curvature are captured by introducing a higher‐order gradient of the deformation as an independent field in the standard continuum. This work explores in detail, a further extension of this continuum to understand the thermal effects on the bending stiffness of fiber bundle in fiber‐reinforced composites. Our proposed model incorporates the temperature of the composite and its bidirectional dependency with the higher‐order gradients of the deformation into the extended mechanical continuum model. The implementation of the model is pursued in the context of multi‐field mixed finite element method and dynamic variational principle. The principle of virtual power enables our extended non‐isothermal continuum to derive an energy‐momentum scheme of higher order. The resulting time‐integrator exhibits physically consistent locking‐ free numerical behavior in dynamical simulations. Our novel approach is illustrated by simple transient dynamic simulations with a hyperelastic, transversely isotropic, polyconvex material behavior. We investigate the conservation of total energy and total momentum in the framework of thermo‐elasticity and study the spatial and temporal convergence for long‐term dynamic simulations with coarser grids and increased accurate numerical solutions. [ABSTRACT FROM AUTHOR]

The concrete-filled double steel tube (CFDST) has been more and more widely used in infrastructure due to its greater moment of inertia compared to the ordinary concrete-filled steel tube (CFST). With the increase in collision accidents occurring in recent years, the research on CFDST under impact needs more attention. To study the dynamic responses of CFDST columns under lateral impact, the finite element package ABAQUS was used to simulate the impact force and mid-span deflection of the column under the coupling action of axial force and lateral impact based on the comparison of experimental data in the literature. The influence of hollow ratio, axial compression ratio, slenderness ratio, impact energy, and material strength on the dynamic responses of the CFDST column are studied. The results show that with the increase in the hollow ratio from 0.3 to 0.8, the residual mid-span deflection of the CFDST column decreases by 77.9%. The mid-span deflection shows an increasing trend following a decreasing one with the axial compression ratio increasing. With the increase in the slenderness ratio from 30 to 60, the plateau impact force decreases by 62.5%, and the residual mid-span deflection increases by 240.5%. The practical formulas for the impact-bearing capacity and residual mid-span deflection of the CFDST column are suggested with high accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The single-crystal lithium hydride (LiH) generally grows in a gradient temperature region with the Bridgman method. A stable and appropriate temperature gradient is crucial in the crystallization process. In this paper, the temperature variation of single-crystal LiH growth is calculated by the finite element method (FEM). It is shown that the LiH compact melted entirely after heating to 750 °C at 10 °C/min in a dual-temperature furnace and holding for 2.4 h. The crystallization margin was 46.5 °C after holding for 5 h. The crystallization margin of LiH at the cone point, respectively, decreased to 33.7 °C, 28.6 °C, 25.6 °C, and 16.5 °C when the upper furnace was maintained at 750 °C, and lower furnace was cooled to 680 °C, 650 °C, 630 °C, and 550 °C, respectively. The optimal conditions for obtaining large size and high-quality LiH single crystals were predicted to be 630 °C at a lower-temperature-zone, 200 mL/min (cooling water flux), and 20 mm/h rise rate of the furnace. Based on the parameters of the above simulation, we synthesized LiH single crystal. X-ray diffraction (XRD) patterns showed that the LiH single crystal exhibited a (2 0 0) crystallographic plane at 44.5° with good chemical stability in air. [ABSTRACT FROM AUTHOR]

With the plethora of data on how CFRP layers enhance RCs under static loads, research on how the reinforced structural components react to unequal lateral impact loads from a derailed train striking metro station columns or a car accident is lacking. A similar motivation inspired the current study, which sought to create a numerical technique backed by actual testing to evaluate RC members with CFRP in a range of unequal lateral impact scenarios. This paper uses explicit nonlinear finite element techniques to numerically analyze the response of unequal lateral impact‐loaded RC members wrapped in (CFRP) layers. Diverse variables related to CFRP, concrete, steel reinforcement, and impact energy are investigated. This kind of thorough analysis provides unique insights to strengthen RC members against unequal lateral impact loads. The effects of internal forces and deflections, as well as absorbed energy on the impact response of CFRP‐RC components, were investigated and verified by prior experimental results. A parametric sensitivity analysis was conducted after the strain characteristics of steel bars confirmed the finite element model, reinforcement ratio, impact velocity, CFRP properties, and ductility index all influence the member's impact response. This study's results will help advance the field's understanding of CFRP‐RC components analysis and design under unequal lateral impact. [ABSTRACT FROM AUTHOR]

Since it is difficult to balance the speed and accuracy of the finite element simulation model of cutting processing, a dynamic mesh refinement algorithm for 3D finite element model is proposed. The functions of the algorithm include mesh refinement area judgment, mesh refinement and transfer of physics fields between new and old meshes. The algorithm is applied to the turning simulation of Ti2AlNb with the secondary development of Abaqus using Python, and the accuracy of the simulation model is verified through experiments. Compared with the simulation results of the local mesh refinement, the simulation using dynamic mesh refinement increases 7.3% in cutting force solution error and increases 0.2% in maximum stress solution error, with an increased 174.2% solution speed. The simulation operation speed is effectively improved while ensuring the calculation accuracy. [ABSTRACT FROM AUTHOR]

An inclined straight combination support pile can play a better role in deep foundation pit support, especially for the protection of adjacent structural pile foundations. We take a section of the construction of a deep foundation pit project in Wuhan City, Hubei Province as the research object. This paper studies the influence of inclined and straight combination support piles on the bending moment and displacement behavior of adjacent pile foundations during the construction of foundation pits under the influence of different factors such as distance from the excavation surface, pit angle effect, inclined pile tilt angle, pit depth to width ratio, and construction conditions on the adjacent pile foundation using a three-dimensional finite element model. According to the research results, as the distance from the excavation surface increases, the bending moment of the adjacent pile foundation decreases, and the closer the pile is to the foundation pit, the greater the horizontal displacement of the pile; the bending moment and displacement of the pile foundation are supported by the pit angle effect. Moreover, the pile bending moment increases with the increase of the pit depth–width ratio, and the maximum displacement point of the pile body gradually moves down from the middle of the pile body to the bottom of the pile foundation as the excavation depth of the pit increases. In addition, the minimum displacement of the adjacent pile foundation is at the top of the pile, and the maximum displacement is at the middle of the pile. Finally, compared with the static analysis, the whole process of dynamic simulation can reflect the dangerous working conditions in the project construction process, and make a more complete safety control construction plan for the project construction process. [ABSTRACT FROM AUTHOR]

Leaf–device interaction can effectively be modeled with a finite element model when proper finite element model parameters are applied. In order to investigate the contact mechanism of picking up sugarcane leaf during the operation of a sugarcane leaf cutting and returning machine, a geometric solid model of sugarcane leaf picking was established. A finite element numerical model to analyze the large deformation problem of flexible bodies was developed in LS-DYNA to simulate the picking process of the returning machine. A dynamic simulation of the sugarcane leaf-picking process was carried out to obtain the change of stress field and the motion posture of the sugarcane leaf and the elastic teeth. The picking process of the picking mechanism, the change in posture of the sugarcane leaves, the change in stress on the sugarcane leaf, the change in the bending angle of the sugarcane leaf and the change in stress on the elastic teeth were analyzed in detail. The results showed that the picking process can be divided into four stages: picking, lifting, pushing and retrieving. The posture changes of sugarcane leaf are "C", logarithmic curve, wavy shape and "V", in turn. During the picking process, the sugarcane blade showed some breakage, the sugarcane vein remained intact, and the elastic teeth did not fail. During the whole picking cycle, the maximum Von Mises stress of the blade, vein and elastic teeth were 22.8 MPa, 17.5 MPa and 900 MPa, respectively. An evaluation criterion of bending angle was creatively put forward to measure the bending deformation of leaves. The trend in the sugarcane leaf bending angle shows that it is largely variable, gradually decreasing, fluctuating and increasing with interval fluctuations. The working process of the picking mechanism was observed through a quick camera experiment. Comparing the experiment with the simulation, the changing trend of the simulation data and experimental data was generally similar. The experimental and simulation values of the average sugarcane leaf bending angle were 27° and 19°, respectively. The relative error of the average bending angle was 29.6%. It was concluded that the developed finite element model is substantial and could be applied to optimize and improve the picking mechanism. In addition, some references were provided for the contact mechanism between the picking mechanism and the sugarcane leaf. [ABSTRACT FROM AUTHOR]

Magnesium alloys are one of the highly promising structural metals. hcp structure makes it less plastic at room temperature, which greatly limits the development of magnesium alloys. The problem of poor plastic deformation of magnesium alloy can be solved by grain refinement methods, and equal channel angle pressing is one of the more effective methods in grain refinement. In this paper, two-dimensional dynamic simulation of equal channel angle pressing of magnesium alloy is carried out by using finite element software DEFORM F2TM. The deformation of magnesium alloy with different of die angles and die corner angles was analyzed. The results show that in the main deformation zone, when the die angles are different, the deformation of the workpiece in the horizontal direction is very uniform. However, in the longitudinal direction of the workpiece, the larger the die angle is, the more uniform the workpiece deformation is. The die corner angle has no significant effect on the uniformity of workpiece deformation in the longitudinal direction, but it has an effect on the dead zone area and workpiece warpage. The dead zone area and workpiece warpage increase with the increase of die angle. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Research & Development / Revista de Investigación & Desarrollo is the property of ECORFAN-Mexico S.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper aims to study the penetration effect of harpoons on space debris to ensure the sustainable development of the space environment and solve the increasingly serious space debris problem. Firstly, a harpoon system was designed to capture space debris. Secondly, based on the Johnson–Cook dynamic constitutive model and fracture failure criterion, the finite element models of aluminum alloy plates were established. Then, the ballistic limit theory for the aluminum alloy target predicted the minimum launch velocity of the harpoon. Finally, the validation experiment was set up to verify the correctness of the model. The results show that the error between the simulation results of the speed for the harpoon embedded in the target and the theoretical results of the ballistic limit is 9.1%, which provides guidance for active space debris removal technology. [ABSTRACT FROM AUTHOR]

Neuronavigation is a computer-assisted technique for presenting three-dimensional images of a patient's brain to facilitate immediate and precise lesion localization by surgeons. Neuronavigation systems use preoperative medical images of patients. In neurosurgery, when the dura mater and arachnoid membrane are incised and the cerebrospinal fluid (CSF) drains out, the brain loses the CSF buoyancy and deforms in the direction of gravity, which is referred to as brain shift. This brain shift yields inaccurate neuronavigation. To reduce this inaccuracy, an intraoperative brain shift should be estimated. This paper proposes a dynamic simulation method for brain-shift estimation combining the moving-particle semi-implicit (MPS) method and the finite element method (FEM). The CSF was modeled using fluid particles, whereas the brain parenchyma was modeled using finite elements (FEs). Node particles were attached to the surface nodes of the brain parenchyma in the FE model. The interaction between the CSF and brain parenchyma was simulated using the repulsive force between the fluid particles and node particles. Validation experiments were performed using a gelatin block. The gelatin block was dipped into silicone oil, which was then gradually removed; the block deformation owing to the buoyancy loss was measured. The experimental deformation data were compared with the results of the MPS-FEM coupled analysis. The mean absolute error (MAE) between the simulated deformation and the average across the four experiments was 0.26 mm, while the mean absolute percentage error (MAPE) was 27.7%. Brain-shift simulations were performed using the MPS-FEM coupled analysis, and the computational cost was evaluated. [ABSTRACT FROM AUTHOR]

Significant effects of the bolt arrangement on the contact characteristics of bolted joints have been demonstrated, which are strongly associated with the dynamic performance of mechanical structures. However, the complexity of interfacial pressure distribution and the randomness of surface microtopography bring challenges to the accurate characterization of the multi-scale contact mechanics. Herein, a hybrid method combining fractal theory with the finite element method (FT-FEM) is proposed, which formulates the interfacial contact evolution in the elastic, elastic-plastic, and fully plastic stages. The complementarity of these two methods makes it possible to reveal the contact mechanism at both micro and macro scales and overcomes difficulties in reflecting the detailed joint contact characteristics in the overall dynamic model. To explore broader implications, FT-FEM is applied to the optimal design of bolt arrangement in an ultra-precision machine tool. Good agreements in calculation results and experimental data validate the accuracy of the proposed FT-FEM and the dynamic simulation. Replacing 15-M10 bolts with 19-M8 bolts results in a 2.9% enhancement in the contact stiffness and a 2.283% attenuation in the vibration response of the workpiece. The results also show that adjusting the bolt arrangement according to the working condition can strengthen the bolted joint effectively. FT-FEM contributes to solving contact problems in various mechanical structures, and the findings have wide practical applications in bolt arrangement optimization. [Display omitted] • A hybrid method for bolted joint modeling considering multi-scale contact mechanics. • New method combines improved fractal theory and finite element method. • Bolt arrangement optimization is carried out applying the method in dynamic analysis. • Experimental validation is done with bolted structures and machine tool. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During the winding process, the filament moves at a high speed with multiple configurations and large deformations, and is acted upon by winding tension, contact force, transverse force, air resistance, and so on. Accurately predicting the trajectory and tension fluctuation of the filament under the high-speed running condition is the basis for regulating winding parameters and ensuring high-quality winding. This paper proposed a novel dynamic approach for modeling the polyester filament winding system. The filament element was established by absolute nodal coordinate formulation. The nonlinear spring and viscous damper elements were used to establish the contact model between the filament and the mechanical parts, and the mechanical model of the influence of the airflow on the filament was established. Through considering the moving filament and all the force factors, the dynamic model of the multi-body coupling system of the filament winding and the corresponding nonlinear dynamic equation were established, and the dynamic equations were solved using MATLAB. An example of the high-speed winding system was simulated and further analyzed, and the simulated trajectory of the moving filament was highly consistent with the experimental image record. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• In vivo finite element model of knee lunge was built by dual fluoroscopic imaging system. • The finite element model was validated by experiments of three-dimensional printed model. • The simulation of in vivo knee movements would help the substantial research of knee. Biomechanical modeling of the knee during motion is a pivotal component in disease treatment, implant designs, and rehabilitation strategies. Historically, dynamic simulations of the knee have been scant. This study uniquely integrates a dual fluoroscopic imaging system (DFIS) to investigate the in vivo dynamic behavior of the meniscus during functional activities using a finite element (FE) model. The model was subsequently validated through experiments. Motion capture of a single-leg lunge was executed by DFIS. The motion model was reconstructed using 2D-to-3D registration in conjunction with computed tomography (CT) scans. Both CT and magnetic resonance imaging (MRI) data facilitated the development of the knee FE model. In vivo knee displacements and rotations were utilized as driving conditions for the FE model. Moreover, a 3D-printed model, accompanied with digital imaging correlation (DIC), was used to evaluate the accuracy of the FE model. To a better inner view of knees during the DIC analysis, tibia and femur were crafted by transparent resin. The availability of the FE model was guaranteed by the similar strain distribution of the DIC and FE simulation. Subsequent modeling revealed that the compressive stress distribution between the medial and lateral menisci was balanced in the standing posture. As the flexion angle increased, the medial meniscus bore the primary compressive load, with peak stresses occurring between 60 and 80° of flexion. The simulation of a healthy knee provides a critical theoretical foundation for addressing knee pathologies and advancing prosthetic designs. [ABSTRACT FROM AUTHOR]