The Finite Element Model of Seated Whole Human Body for Vibration Investigations of Lumbar Spine in Complex System

Dong, Ruichun; Guo, Qianjian; Yuan, Wei; Du, Wei; Yang, Xianhai; Zhao, Yanjun

doi:10.1109/access.2020.3007940

Cited by 14 publications

(7 citation statements)

References 38 publications

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“…The nite element model in this study was based on an upright seated human, which allowed the spine to be simpli ed as a vertical rod 21 , and the center of gravity of the upper body is on the axis of the vertical rod. Under the vertical excitation, the entire rod moved along the vertical direction.…”

Section: Discussionmentioning

confidence: 99%

Study on the Vibration Behavior of the Head of an Upright Seated Human under Vertical Whole-Body Vibration

Dong,

Lu,

Liu

et al. 2023

Preprint

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To investigate the response behavior of the human head in upright sitting, a seated human finite element model with detailed skeletal and muscular soft tissues was created based on human biomechanics. The vertical first-order resonant frequency of each segment model was calculated by modal analysis, and the seat-to-head transmissibility (STHT) of the seated human finite element model was calculated by the random response method. The model had been verified through simulation and experimental studies. It was found that the upright seated human under vertical whole-body vibration showed an apparent resonance phenomenon around 5.7 Hz. The maximum value of the direct-axis response of the head in the sagittal plane was located in the posterior occipital region, where the STHT was 10% larger than that at the crown and 23% larger than that at the forehead. The direct-axis responses of the head in various positions within the coronal plane were almost identical. The maximum value of the cross-axis response was located at the crown of the head, and the response peaks in the sagittal and coronal planes were symmetrical about this point. Moreover, the maximum difference of direct-axis response at different positions reached 119%. Additionally, we found that the seated human body had not only Significant vertical and fore-aft displacements but also head rotation, leading to complex coupling vibration of the head. This study provides a reference and theoretical basis for the seated human head response measurement, model creation, and vibration comfort evaluation.

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Section: Discussionmentioning

confidence: 99%

Study on the Vibration Behavior of the Head of an Upright Seated Human under Vertical Whole-Body Vibration

Dong,

Lu,

Liu

et al. 2023

Preprint

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“…The FE is a universal method to identify the dynamic parameters of complex components [25][26][27]. In this section, the radial deformation of the shaft hole under static action is obtained through FE statics analysis, and then the radial stiffness of the shaft hole in different directions can be calculated.…”

Section: A Fe Verification Model For the Directional Stiffness Of The...mentioning

confidence: 99%

A Method for Predicting the Boring Topography Error of Shaft Hole on a Thin-Walled Box Based on a Proposed Dynamic Model

2023

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Traditional boring dynamic model ignores the effect of the uneven radial stiffness of the shaft hole of the thin-walled box on the boring vibration characteristic, which will lead to the deviation in the prediction for both the cutting force and the surface topography of the machining hole. To address this shortcoming, a new calculation model of the equivalent radial stiffness of the shaft hole is proposed and then validated by the finite element (FE) method. On this basis, a boring dynamic model of the shaft hole is developed, and an experimental study on the dynamic characteristics of the shaft hole boring is carried out to verify the correctness and effectiveness of the proposed dynamic model. Moreover, a prediction method for the surface topography error of the machined shaft hole is presented based on the proposed dynamic model. Finally, the comparison investigation on the hole machined surface topography predicted by the proposed method and measured in practice is carried out. The results show that the proposed theoretical models and method can achieve accurate predictions for both the boring cutting force and the machined surface topography error of the shaft hole on the thin-walled box. This study can provide a theoretical basis for machining error control and process optimization of the fine boring of the thin-walled transmission box.INDEX TERMS Thin-walled box, shaft hole machining, boring dynamic model, surface topography prediction.

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“…We simulate the fNIRS process using a subject's forehead FEM model [50,51]. The Matlab toolbox, NIRFAST, was used.…”

Section: Numerical Simulationmentioning

confidence: 99%

“…Fig. 4a shows a 3-dimensional head model reconstructed from an fMRI image using the NIRFAST [50,51], consisting of 58,818 tetrahedrons of size 3.5 mm. We can use a finer mesh at the cost of longer computational time.…”

Section: A Fem Mesh and Optical Topologymentioning

confidence: 99%

Multi-Channel-Based Differential Pathlength Factor Estimation for Continuous-Wave fNIRS

Huang

Hong

2021

IEEE Access

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Functional near-infrared spectroscopy (fNIRS) in brain imaging needs to be robust to subjectwise variability. The use of a fixed differential pathlength factor (DPF) per wavelength for the entire brain will degrade the accuracy of hemodynamic responses. Since the tissue composition varies within the brain, correct DPF values should be used for various emitter-detector distances and brain regions. In this paper, a DPF estimation method combining a state-space model of the modified Beer-Lambert law (mBLL), a parameter model for estimating the reduced scattering coefficients, and dual square-root cubature Kalman filters (SCKFs) is proposed. To validate the proposed method, known light intensities (six channels, two wavelengths) and reference DPFs are generated using NIRFAST (a Matlab toolbox) using a presumed paradigm, known tissue properties, a Balloon model, and a finite element head model consisting of 58,818 mesh elements. Then, the DPF values are estimated using a Jacobian matrix from the head model and the mBLL. The results show that the estimated concentration changes correlate well with the reference data. Also, the estimated DPFs showed relative errors less than 1.33% maximum and 0.75% on average. A onetailed t-test revealed that the estimated DPFs matched the reference DPFs with more than 99.9% confidence. The developed method can efficiently access the actual DPFs even if emitter-detector distances vary significantly and the tissue properties are not uniform. With the developed state-space models for dual SCKFs, real-time estimation of the DPFs from one experiment to another has become plausible.INDEX TERMS Differential pathlength factor (DPF), functional near-infrared spectroscopy (fNIRS), Kalman filter, state-space method, finite element method (FEM)

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The Finite Element Model of Seated Whole Human Body for Vibration Investigations of Lumbar Spine in Complex System

Cited by 14 publications

References 38 publications

Study on the Vibration Behavior of the Head of an Upright Seated Human under Vertical Whole-Body Vibration

Study on the Vibration Behavior of the Head of an Upright Seated Human under Vertical Whole-Body Vibration

A Method for Predicting the Boring Topography Error of Shaft Hole on a Thin-Walled Box Based on a Proposed Dynamic Model

Multi-Channel-Based Differential Pathlength Factor Estimation for Continuous-Wave fNIRS

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