Experimental Flexibility Measurements for the Development of a Computational Head-Neck Model Validated for Near-Vertex Head Impact

Camacho, Daniel; Nightingale, Roger W.; Robinette, Joseph J.; Vanguri, Sanjay K.; Coates, Douglas J.; Myers, Barry S.

doi:10.4271/973345

Cited by 74 publications

(79 citation statements)

References 42 publications

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“…As no other data on disc stiffnesses can be found Moroney's values have been used for axial rotation, lateral bending, and all shear stiffness coefficients. A recent study on flexion and extension of the cervical spine presents nonlinear load-displacement curves at various levels [25]. Although the stiffness curves reported represent the response of entire motion segments, with ligaments and facet joints left intact, theses values can still be used to define the flexion/extension response of the disc.…”

Section: Modelling Intervertebral Discsmentioning

confidence: 99%

“…The graphs show the moment rotation curves for each level of the spine up to a maximum of ±10 Nm. Also shown on each graph are the moment rotation functions for each cervical level as defined by Camacho et al [25] up to ±2 Nm and the average ± SD rotation at 1.8 Nm as reported by Moroney et al [23]. For the upper cervical spine segment, C0-C2, the mean (±SD) rotation at 1.…”

Section: Motion Segment Response To Large Loadsmentioning

confidence: 99%

“…From the intact segment tests it was found that the linear stiffness was 0.43 and 0.73 Nm/deg for flexion and extension, respectively, whereas for the isolated disc segments the stiffness was found to be 0.21 and 0.32 Nm/deg. It is therefore reasonable to divide the flexion/extension stiffness functions, presented by Camacho et al [25], by 2 to give the approximate non-linear response of the intervertebral discs. This approach has also been used by Van Der Horst [5].…”

Section: Modelling Intervertebral Discsmentioning

confidence: 99%

“…This step of the validation process follows the procedure described by Van Der Horst [5], who used the experimental results of Camacho et al [25] to validate an extension of the De Jager [2] multi-body model in the software package MADYMO. Camacho et al [25] published quasi-static flexion-extension characteristics of ten human cadaveric ligamentous cervical spine specimens (the skull was also left attached during testing). For testing the specimens were turned upside down and fixed in a loading frame.…”

Section: Ligamentous Cervical Spine Responsementioning

confidence: 99%

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Development of a multi-body computational model of human head and neck

Lopik

Acar

2007

Proceedings of the Institution of Mechanical Engineers, Part K:

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Citation: VAN LOPIK, D.W. and ACAR, M., 2007. Development of a multibody computational model of human head and neck. Proceedings of the IMechE, Part K: Journal of Multi-body Dynamics, 221 (2), pp. Additional Information:• This is an article from the journal, Proceedings of the IMechE, Abstract: Experimental studies using human volunteers are limited to low acceleration impacts while whole cadavers, isolated cervical spine specimens, and impact dummies do not normally reflect the true human response. Computational modelling offers a cost effective and useful alternative to experimental methods to study the behaviour of the human head and neck and their response to impacts to gain insight into injury mechanisms.This article reports the approach used in the development of a detailed multi-body computational model that reproduces the head and cervical spine of an adult in the upright posture representing the natural lordosis of the neck with mid-sagittal symmetry. The model comprises simplified but accurate representations of the nine rigid bodies representing the head, seven cervical vertebrae of the neck, and the first thoracic vertebra, as well as the soft tissues, i.e. muscles, ligaments, and intervertebral discs. The rigid bodies are interconnected by non-linear viscoelastic intervertebral discs elements in flexion and extension, non-linear viscoelastic ligaments and supported through frictionless facet joints. Eighteen muscle groups and 69 individual muscle segments of the head and neck on each side of the body are also included in the model. Curving the muscle around the vertebrae and soft tissues of the neck during the motion of the neck is also modelled. Simulation is handled by the multi-body dynamic software MSC.visuaNastran4D. Muscle mechanics is handled by an external application, Virtual Muscle, in conjunction with MSC.visuaNastran4D that provides realistic muscle properties. Intervertebral discs are modelled as non-linear viscoelastic material in flexion and extension but represented by 'bushing elements' in Visual Nastran 4D, which allows stiffness and damping properties to be assigned to a joint with required number of degrees of freedom of the motion. Ligaments are modelled as non-linear viscoelastic spring-damper elements.As the model is constructed, the cervical spine motion segments are validated by comparing the segment response to published experimental data on the load-displacement behaviour for both small and large static loads. The response of the entire ligamentous cervical spine model to quasi-static flexion and extension loading is also compared to experimental data to validate the model before the effect of muscle stiffening is included. Moreover the moment-generating capacity of the neck muscle elements has been compared against in vivo experimental data.The main and coupled motions of the model segments are shown to be accurate and realistic, and the whole model is in good agreement with experimental findings from actual human cervical spine specimens. It has been shown that the mode...

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Section: Modelling Intervertebral Discsmentioning

confidence: 99%

Section: Motion Segment Response To Large Loadsmentioning

confidence: 99%

Section: Modelling Intervertebral Discsmentioning

confidence: 99%

Section: Ligamentous Cervical Spine Responsementioning

confidence: 99%

See 2 more Smart Citations

Development of a multi-body computational model of human head and neck

Lopik

Acar

2007

Proceedings of the Institution of Mechanical Engineers, Part K:

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show abstract

“…The model consists of nine rigid bodies with detailed geometry representing the head, seven cervical vertebrae, and the first thoracic vertebrae. The material properties of the soft tissue and the rigid bodies are based on the most recent experimental data reported in the literature [18,21,22] and data used by de Jager [8] and van der Horst [10]. Nineteen muscle groups of the head and neck are incorporated in the model.…”

Section: The Multi-body Modelmentioning

confidence: 99%

Viscoelastic finite element analysis of the cervical intervertebral discs in conjunction with a multi-body dynamic model of the human head and neck

Esat

Acar

2008

Proc Inst Mech Eng H

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This article presents the effects of the frontal and rear-end impact loadings on the cervical spine components by using a multibody dynamic model of the head and neck, and a viscoelastic finite element (FE) model of the six cervical intervertebral discs. A threedimensional multi-body model of the human head and neck is used to simulate 15 g frontal and 8.5 g rear-end impacts. The load history at each intervertebral joint from the predictions of the multi-body model is used as dynamic loading boundary conditions for the FE model of the intervertebral discs. The results from the multi-body model simulations, such as the intervertebral disc loadings in the form of compressive, tensile, and shear forces and moments, and from the FE analysis such as the von Mises stresses in the intervertebral discs are analysed. This study shows that the proposed approach that uses dynamic loading conditions from the multi-body model as input to the FE model has the potential to investigate the kinetics and the kinematics of the cervical spine and its components together with the biomechanical response of the intervertebral discs under the complex dynamic loading history.

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A comparative study on dynamic stiffness in typical finite element model and multi‐body model of C6–C7 cervical spine segment

Wang

et al. 2015

Numer Methods Biomed Eng

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In contrast to numerous researches on static or quasi-static stiffness of cervical spine segments, very few investigations on their dynamic stiffness were published. Currently, scale factors and estimated coefficients were usually used in multi-body models for including viscoelastic properties and damping effects, meanwhile viscoelastic properties of some tissues were unavailable for establishing finite element models. Because dynamic stiffness of cervical spine segments in these models were difficult to validate because of lacking in experimental data, we tried to gain some insights on current modeling methods through studying dynamic stiffness differences between these models. A finite element model and a multi-body model of C6-C7 segment were developed through using available material data and typical modeling technologies. These two models were validated with quasi-static response data of the C6-C7 cervical spine segment. Dynamic stiffness differences were investigated through controlling motions of C6 vertebrae at different rates and then comparing their reaction forces or moments. Validation results showed that both the finite element model and the multi-body model could generate reasonable responses under quasi-static loads, but the finite element segment model exhibited more nonlinear characters. Dynamic response investigations indicated that dynamic stiffness of this finite element model might be underestimated because of the absence of dynamic stiffen effect and damping effects of annulus fibrous, while representation of these effects also need to be improved in current multi-body model. Copyright © 2015 John Wiley & Sons, Ltd.

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Experimental Flexibility Measurements for the Development of a Computational Head-Neck Model Validated for Near-Vertex Head Impact

Cited by 74 publications

References 42 publications

Development of a multi-body computational model of human head and neck

Development of a multi-body computational model of human head and neck

Viscoelastic finite element analysis of the cervical intervertebral discs in conjunction with a multi-body dynamic model of the human head and neck

A comparative study on dynamic stiffness in typical finite element model and multi‐body model of C6–C7 cervical spine segment

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