# A Female Multi-Body Head-and-Neck Model and Validation for Rear Impact Simulations
###### Abstract  
In this study, the development and validation of a 35 th percentile female multi-body head-neck model are presented to study miphal-related disorders in rear-end impacts. The volunteer sled tests conducted by the Japan Automobile Research Institute (JARI) with an impact velocity of 7.9 km/h have been utilized for the validation process. The proposed method in the development of the female multi-body head-neck model is characterized by its simplicity, efficiency, and capability of the biofidelic responses. Compared to the volunteer response corridors, the model has maximum absolute errors of 3.67 mm and 2.45 deg in head translational and head angular displacements, respectively, in the most optimum solution. The outcomes demonstrate that this head-neck model for a 35 th-percentile female can give a high level of accuracy in rear impact simulations. rear impact; multi-body modeling; female dummies; head and neck model 2025  
Over the past three decades, the literature has seen the introduction of several multi-body head-neck models. These multi-body models [5] have been built for different purposes. [PERSON] et al. [6] created a neck model using data from a human cadaver and the MR images of a male human volunteer to generate biofidelic responses for the muscles. This model was used to define the range of tolerance to tensile loading. [PERSON] [7] improved [PERSON]'s male model [8] and embedded it into a human-body model. This model gave more realistic muscle force lines and was validated for lateral, frontal, and rear impact loadings. [PERSON] et al. [9] model was designed only for the vertebrae between C2-C7 with the aid of computed tomography images. The model was then used to simulate the flexion-extension motion of the cervical spine for disc prosthesis. In the model, the stiffness of the springs was considered linear, and the stiffness coefficients were taken from the literature based on experiments conducted with human cadaver cervical spines. Also, the viscoelastic behavior was neglected. In [PERSON] et al. [10], the vertebrae between C2 and T1 were modeled. The verteba geometries were obtained from the tomography images of a female subject who was 59 years old. The intervertebral disc joints having nonlinear viscoelastic properties were used. The disc stiffnesses were lumped at a single point between each pair of vertebrae. The objective was to estimate the kinematics and the dynamics of the cadaver cervical spine. This model is very limited because it was developed by using the data from a 59-year-old female only. Hence, the model does not represent the general population. [PERSON] [2] built a model of the head, neck, and the first thoracic verteba, including the soft tissues using the multi-body dynamics method. Nonlinear viscoelastic material was used for the intervertebral discs. The developed male model was able to simulate the local and global motion of the head relative to the upper torso. [PERSON] et al. [11] created a whole head-neck model to estimate the wear in cervical disc implants. This model was designed by utilizing computed tomography scans of a 24-year-old volunteer with 1.80 m of height and 90 kg of mass. Each verteba had a simple geometry, and intervertebral discs were represented by passive elements. In [PERSON]'s study [12], the aim was to create a model to predict the motion of the cervical spine, define the tissue loads, and maintain the balance of the head-neck. This model was evaluated by using only three volunteers who did not have neck pain. [PERSON] et al. [13] created a model that included seven vertebrae, a head, and T1 (the first thoracic verteba). This model was evaluated using experimental data to examine the motion of the trunk and the motion of the head under gravity. Starting from the mid-1990s, [PERSON] et al. [14] developed a male multi-body head-neck model, working only in the sagittal plane. [PERSON] [8] model was the first detailed male head-neck model, which included soft tissues that were lumped into the intervertebral joints.