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

Abstract

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.

A forward dynamics simulation of human lumbar spine flexion predicting the load sharing of intervertebral discs, ligaments, and muscles

“…In vitro and in vivo measurements have been accompanied by computer simulations (in silico) in order to determine the internal dynamics of the spine. In contrast to experimental testing, computer models allow biomechanical analyses of the spine in a more efficient, ethically acceptable and completely reproducible manner (Esat and Acar 2008;Gatton et al 2011). To achieve this, all relevant structural elements, e. g. vertebrae, IVDs, spinal ligaments, and muscletendon complexes (MTCs); their material properties; and an appropriate verification of the whole model need to be taken into account to accurately predict the internal dynamics and the load distribution of the spine, and to analyse the functionality and purpose of the different biological structures.…”

Surrogate modeling of multiscale models using kernel methods

“…In the context of the spine, the scale bridging between the multi‐body system and a finite‐element model has been applied using co‐simulations or by performing pre‐computations with an approximation of the mechanical response using surrogate models to define the bushing element , which is the approach investigated in this contribution.…”

“…The simplest models available are based on a computationally cheap multi-body system (cf. [53][54][55][56][57][58] among others). Herein, all bones of the skeleton (including the vertebrae) are modeled as rigid bodies with a reduction of their three-dimensional (3D) properties at their respective centers of gravity.…”

“…Moreover, Dirichlet boundary conditions allow to prescribe a solid displacement N u S as well as a hydraulic pore-fluid pressure N P on the surface of the intervertebral disc. To couple multi-body systems with continuum-mechanically based finite-element models, scalebridging and homogenization techniques need to be applied to transfer continuum quantities like stresses and strains of the 'micro' finite-element model D to integral forces P C and displacements P D used in the 'macro' multi-body system C and vice versa; compare Figure 1 In the context of the spine, the scale bridging between the multi-body system and a finite-element model has been applied using co-simulations [55,56] or by performing pre-computations with an approximation of the mechanical response P C using surrogate models to define the bushing element [24], which is the approach investigated in this contribution.…”

Simulated Effects of Head Movement on Contact Pressures Between Headforms and N95 Filtering Facepiece Respirators-Part 1: Headform Model and Validation

“…The cervical spine model can be connected to a head model for controlling the head movements. Different kinds of head movements, including flexion, extension, axial rotation, and bending, were simulated by applying external loads to the FE cervical spine model (Van der Horst, 2002; Esat et al ., 2005; Hedenstierna and Halldin, 2008; Esat and Acar, 2009; Hedenstierna et al , 2009). The above existing head models do not include any skin or fatty tissue.…”