Biomechanical modelling of the whole human spine for dynamic analysis

Developing computational models of the human spine has been a hot topic in biornechanical research for a couple of decades in order to have an understanding of the behaviour of the whole spine and the individual spinal parts under various loading conditions. The objectives of this thesis are to develop a biofidefic multi-body model of the whole human spine especially for dynamic analysis of impact situations, such as frontal impact in a car crash, and to generate finite element (FE) models of the specific spinal parts to investigate causes of injury of the spinal components. As a proposed approach, the predictions of the multi-body model under dynamic impact loading conditions, such as reaction forces at lumbar motion segments, were utilised not only to have a better understanding of the gross kinetics and kinematics of the human spine, but also to constitute the boundary conditions for the finite element models of the selected spinal components. This novel approach provides a versatile, cost effective and powerful tool to analyse the behaviour of the spine under various loading conditions which in turn helps to develop a better understanding of injury mechanisms

Effects of table design in railway carriages on pregnant occupant safety

This paper focuses on safety investigations for pregnant occupants, in particular, on their interactions with an interior feature, fixed bay tables, in railway vehicles. The computational pregnant occupant model Expecting has represented pregnant travellers in railway vehicle environments. Expecting is a computational pregnant occupant model developed at Loughborough University, in order to investigate the dynamic response of pregnant women to impacts. It has been successfully utilised by the authors in earlier studies, in various automobile crash investigations, such as frontal impacts with real and simplified crash pulses. In this study, a model of a network train carriage is generated and used together with Expecting to assess the suitability of fixed bay table designs for pregnant occupants. Investigations of potential injuries in this paper are believed to contribute to the design of more suitable interior features and hence improve safety and quality of life for pregnant women as travellers in railway vehicles

Seat belt designs to protect pregnant vehicle occupants

Various restraint systems to protect vehicle occupants in case of an accident have been specifically designed for pregnant women and the ideas are filed for patents. The concepts cover a wide range of designs; from ‘add-on’ to standard 3-point seat belt solutions to relatively complex mechatronics applications. Auxiliary tools and equipments to offer lap belt solutions constitute the majority of the reviewed patents. Designs also vary according to their working principles. Some designs exclusively focus on the lap belt part of the seat belt, whereas some others attempt to resolve the problem from a broader perspective, offering overall seat belt solutions with or without the use of standard seat belt. In this article around forty patented ideas on seat belt designs for pregnant women are reviewed, classified and presented, highlighting the working principles and inventors’ claims

Pregnant driver injury investigations through modelling and simulation of full-frontal crashes with and without airbags

Road traffic accidents have become increasingly important element in maternal deaths. It is important to investigate the injury mechanisms and injury levels that pregnant women may be subjected to in order to improve transport safety. The three dimensional computational model ‘Expecting’, which embodies a detailed multi-body model of a fetus in a finite element model of a uterus with a placenta, is developed at Loughborough University. The model is designed to simulate dynamic loading conditions that pregnant occupant may experience. In this study, ‘Expecting’ is used to study the kinematics of pregnant occupants to predict the injury levels to the pregnant driver in frontal crashes. The implications of ‘No restraint’, ‘Seat Belt Only’ and ‘Seat Belt & Airbag’ cases are investigated for various crash severities, from 15 to 45 kph. Crash analysis injury criteria such as Head Injury Criterion (HIC), 3ms maximum, Combined Thoracic Index (CTI) and Viscous Criterion (Max VC) are used. The results suggest that the frontal airbag together with the correctly worn seatbelt provide better protection for the pregnant drivers

Pregnant driver injury investigations in oblique crashes

Kinetics and kinematics of an oblique impact are different when compared to frontal collisions. The objective of this research is to simulate various oblique crash scenarios that pregnant drivers may experience by using the computational pregnant occupant model, ‘Expecting’ and investigate potential injuries that pregnant drivers may suffer. Half-sine acceleration pulses representing crash speeds 15kph to 45kph are used in the simulations. Oblique impact simulations are conducted both from the nearside and the farside (offside) of the vehicle. The placental abruption and hence fetus mortality risks during oblique crashes are compared with the full-frontal impact cases

Investigation into suitability of current ATDs to represent ageing drivers

Ageing car occupants are expected to become a larger part of the driver and passenger population in developed countries in the future. Currently, Anthropomorphic Test Devices (ATDs) are essential tools to assess safety of automobiles; however, they do not fully embody the features of all occupant groups in the world population. This study investigates the features of ageing drivers. The data are collected and analysed with respect to age and gender. Information particularly on driver-automobile interaction is provided in the form of distances and angles measured in-car. The physical characteristics of existing ATDs are investigated and compared with the anthropometric data of ageing drivers. Comparisons indicate that the current ATDs do not incorporate some of the features of ageing drivers. The requirements of future ATDs such as sitting height, abdominal depth and posture are discussed. These specifications are essential for the development of new ATDs representing ageing drivers. © 2013 Taylor and Francis Group, LLC

Hybrid foetus with an FE head for a pregnant occupant model for vehicle safety investigations

‘Expecting’, a computational pregnant occupant model, developed to simulate the dynamic response to crash impacts, possesses anthropometric properties of a fifth percentile female at around the 38th week of pregnancy. The model is complete with a finite element uterus and a multi-body foetus which is a novel feature in models of this kind. In this paper, the effect of incorporating a foetus with a finite element head into ‘Expecting’ is investigated. The finite element head was developed using detailed anatomic geometry and projected material properties. Then it was integrated with the ‘Expecting’ model and validated using the lap belt loading and the rigid bar impact tests. The model is then used to simulate frontal impacts at a range of crash severities with seatbelt and airbag, seatbelt only, airbag only as well as no restraint cases to investigate the risk of placental abruption and compare it with the model featuring the original multi-body foetus. The maximum strains developed in the utero-placental interface are used as the main criteria for foetus safety. The results show comparable strain levels to those from the multi-body foetus. It is, therefore, recommended to use the multi-body foetus in simulations as the computation time is more favourable