Active Child Models for Traffic Safety Research, Interim Report 1, October 2012

The project Active Child Models for Traffic Safety Research is funded by Folksams Forskningsstiftelse. The overall aim is to increase the safety of child car occupants and thereby reduce the number of traffic induced injuries in 3 to 12 year-old children. This will be done by creating a computer model of a child that includes active musculature. The model will be used to reproduce emergency manoeuvres with biofidelic response at low acceleration levels. Literature on child safety has been reviewed with a main focus on child numerical models. Very few child models exist and for most of them, their response is validated against Anthropometric Test Devices (ATDs) certification corridors and not paediatric data. Models of children and child sized ATDs are either finite element or multi body models. Finite element models are more likely to predict injuries and contacts, whereas multi body models can preferably be used to reproduce kinematics in long duration events like emergency manoeuvres. Because of this, it has thus been decided to first work with child multi body models in the MADYMO code (TASS, Rijswijk, the Netherlands). The models that will be studied are the 6 and 10 year-old child facet models and the Q6 and Hybrid III 6 year-old ATDs available in MADYMO as well as the 6 year-old pedestrian model previously developed by Jikuang Yang at Chalmers University of Technology. Simulation activities have been planned and the models’ responses will be analysed and compared with kinematics data of child volunteers in emergency manoeuvres and sled tests. Then, based on their performance, one model will be chosen to implement active musculature. Extra experimental data for tuning and validation of the model may be required. As a consequence, new experiments on child volunteers are planned, including the acquisition of muscular activity. The model response will be compared to those results. Based on the active child multi body model capability to reproduce pre-crash events, it will be discussed and decided in January 2013 whether to continue with a multi body model or start the same process with a finite element model. In the long term, the active child model will be used to reproduce both pre-crash and in-crash events and help understanding the protective principles of forward facing children and how they interact with current and future vehicle safety systems and child restraints

The straws effect on activity levels, straw-directed behavior and tail biting in fattening pigs

Pigs are omnivorous animals and their natural food sources are spread over a large home range area. Under natural conditions pigs spend a large part of the daylight period foraging and exploring their surroundings. In today’s intense farming systems pigs that have access to straw spend about 20% of their active time to straw manipulation. Pigs with access to straw are more active than pigs kept on a fully slatted floor, and pigs with access to straw also perform less adverse pen-matedirected behaviors, like tail biting. The aim of this study was to investigate how fattening pig’s activity levels change within the daylight period. This study also investigated if the level of activity was affected by the amount of straw the pigs that were provided with and where the pigs aim their exploratory behavior, i.e. towards the straw or other pigs. This study was performed over a five-day period on a conventional pig farm and the activity levels and the behavior of the pigs were recorded on 80 fattening pigs. They were divided in to two groups (8x 10 pigs per pen), 40 pigs in each group, one of the groups were given twice as much straw as the other group. The group’s behaviors were recorded at 7 occasion’s over the daylight period with instantaneous scan sampling. The average activity levels increased significantly in the group of pigs that had access to more straw. The control group had a more evenly distributed activity over the daylight period while the group with more straw hade a more varying activity levels. The group with more straw performed significantly more straw-directed behavior than the control group. Both groups performed evenly distributed strawdirected behavior under the daylight period. The amount of straw did not seem to influence the amount of pen-mate directed behavior in this study. Both groups were most active at 07:00 and 15:00 and both groups exhibited a clear rise in pen-mate directed behavior at 07:00 and 15:00. Considering the fact that pigs, by nature, are very active and curious animals, I consider that the increase in activity levels and straw-directed behavior in pigs that had access to more straw is a sign of an improved welfare

Biomekanik och skadeprevention

Den grundläggande forskning inom biomekanik med fokus på människans skadetoleranser och skyddsprinciper inom trafiksäkerhet kan användas inom sport och idrott för att minimera skaderisker, med bibehållen eller ökad idrottsprestation

Generic finite element models of human ribs, developed and validated for stiffness and strain prediction - To be used in rib fracture risk evaluation for the human population in vehicle crashes

To enable analysis of the risk of occupants sustaining rib fractures in a crash, generic finite element models of human ribs, one through twelve, were developed. The generic ribs representing an average sized male, were created based on data from several sources and publications. The generic ribs were validated for stiffness and strain predictions in anterior-posterior bending. Essentially, both predicted rib stiffness and rib strain, measured at six locations, were within one standard deviation of the average result in the physical tests. These generic finite elements ribs are suitable for strain-based rib fracture risk predictions, when loaded in anterior-posterior bending. To ensure that human variability is accounted for in future studies, a rib parametric study was conducted. This study shows that the rib cross-sectional height, i.e., the smallest of the cross-sectional dimensions, accounted for most of the strain variance during anterior-posterior loading of the ribs. Therefore, for future rib fracture risk predictions with morphed models of the human thorax, it is important to accurately address rib cross-sectional height

Epidemiology of Equestrian Accidents: a Literature Review

Purpose: This manuscript aimed to present a review of the literature pertaining to horse riding and other horse-related injuries. Method: A review of the literature was performed, searching for appropriate terms with regards to horse accidents, horse riding injuries and protective clothing for the horse riding context. The literature review search returned 151 relevant full-text articles, with 71 of these detailing the overall injury epidemiology of horse-related accidents. Most of these studies were conducted in the USA and used a retrospective review of hospital data methodology. Results: Of the 71 articles investigated, 60 suggested that those most frequently involved in horse-related accidents are young females and 97% of papers investigating injury mechanisms found the most commonly involved was a fall from horseback. It was suggested in multiple studies that these injury events mostly occurred in warm weather conditions, when the horse behaved in an unexpected manner. Injury type and location varied by the primary mechanism of injury; but frequently involved body regions were the head and upper extremities, and the most common injuries observed were fractures and soft tissue injuries. Neurological trauma was reported by all relevant studies to be the most frequent cause of fatality. Conclusion: Some improvements in horse-related accident numbers and outcomes have been observed with the development and introduction of protective devices such as helmets and vests. Yet despite the benefits of helmet and vest usage, there is evidence to suggest helmets do not perform as well as they could. Further work could investigate improvements in safety measures and risk factors associated with fatalities

Analyses of injuries to equestrians in a Swedish district over a 16-year period

Horse riding is a popular, yet dangerous, sport, and as such, horse-related injuries contribute considerably to the total number of people hospitalized every year. While some investigations have explored this public health issue, many have focused only on hospital registrations or insurance information, while neglecting the cases where the rider may have not required hospitalization. This study investigated the pattern of equestrian injuries in Sweden and examined factors for predicting hospitalized injuries, using visits to hospital, local medical centers, and public dental services. Data were gathered over a 16-year period at all medical facilities within Skaraborg, Sweden, and retrospectively reviewed. There were 7815 horse-related injury events during the study period. The sample of horse-related injuries were largely represented by females (88%) and those aged between 10 and 20\ua0years old. Injuries commonly took place during private/leisure time (90.8%) and in the afternoon. Logistic regression analysis found that older riders were significantly more likely to be admitted to hospital (OR\ua0=\ua01.013), while female riders were less likely to be admitted than males (OR\ua0=\ua00.739). The numbers of people registering at medical facilities due to horse-related injuries are increasing. Therefore, improved intervention measures must be further investigated

Passenger muscle responses in lane change and lane change with braking maneuvers using two belt configurations: Standard and reversible pre-pretensioner

Objective: The introduction of integrated safety technologies in new car models calls for an improved understanding of the human occupant response in precrash situations. The aim of this article is to extensively study occupant muscle activation in vehicle maneuvers potentially occurring in precrash situations with different seat belt configurations. Methods: Front seat male passengers wearing a 3-point seat belt with either standard or pre-pretensioning functionality were exposed to multiple autonomously carried out lane change and lane change with braking maneuvers while traveling at 73 km/h. This article focuses on muscle activation data (surface electromyography [EMG] normalized using maximum voluntary contraction [MVC] data) obtained from 38 muscles in the neck, upper extremities, the torso, and lower extremities. The raw EMG data were filtered, rectified, and smoothed. All muscle activations were presented in corridors of mean \ub1 one standard deviation. Separate Wilcoxon signed ranks tests were performed on volunteers’ muscle activation onset and amplitude considering 2 paired samples with the belt configuration as an independent factor. Results: In normal driving conditions prior to any of the evasive maneuvers, activity levels were low (<2% MVC) in all muscles except for the lumbar extensors (3–5.5% MVC). During the lane change maneuver, selective muscles were activated and these activations restricted the sideway motions due to inertial loading. Averaged muscle activity, predominantly in the neck, lumbar extensor, and abdominal muscles, increased up to 24% MVC soon after the vehicle accelerated in lateral direction for all volunteers. Differences in activation time and amplitude between muscles in the right and left sides of the body were observed relative to the vehicle’s lateral motion. For specific muscles, lane changes with the pre-pretensioner belt were associated with earlier muscle activation onsets and significantly smaller activation amplitudes than for the standard belt (P <.05). Conclusions: Applying a pre-pretensioner belt affected muscle activations; that is, amplitude and onset time. The present muscle activation data complement the results in a preceding publication, the volunteers’ kinematics and the boundary conditions from the same data set. An effect of belt configuration was also seen on previously published volunteers’ kinematics with lower lateral and forward displacements for head and upper torso using the pre-pretensioner belt versus the standard belt. The data provided in this article can be used for validation and further improvement of active human body models with active musculature in both sagittal and lateral loading scenarios intended for simulation of some evasive maneuvers that potentially occur prior to a crash

The Effect of Seat Back Inclination on Spinal Alignment in Automotive Seating Postures

Experimental studies have demonstrated a relationship between spinal injury severity and vertebral kinematics, influenced by the initial spinal alignment of automotive occupants. Spinal alignment has been considered one of the possible causes of gender differences in the risk of sustaining spinal injuries. To predict vertebral kinematics and investigate spinal injury mechanisms, including gender-related mechanisms, under different seat back inclinations, it is needed to investigate the effect of the seat back inclination on initial spinal alignment in automotive seating postures for both men and women. The purpose of this study was to investigate the effect of the seat back inclination on spinal alignments, comparing spinal alignments of automotive seating postures in the 20\ub0 and 25\ub0 seat back angle and standing and supine postures. The spinal columns of 11 female and 12 male volunteers in automotive seating, standing, and supine postures were scanned in an upright open magnetic resonance imaging system. Patterns of their spinal alignments were analyzed using Multidimensional Scaling presented in a distribution map. Spinal segmental angles (cervical curvature, T1 slope, total thoracic kyphosis, upper thoracic kyphosis, lower thoracic kyphosis, lumbar lordosis, and sacral slope) were also measured using the imaging data. In the maximum individual variances in spinal alignment, a relationship between the cervical and thoracic spinal alignment was found in multidimensional scaling analyses. Subjects with a more lordotic cervical spine had a pronounced kyphotic thoracic spine, whereas subjects with a straighter to kyphotic cervical spine had a less kyphotic thoracic spine. When categorizing spinal alignments into two groups based on the spinal segmental angle of cervical curvature, spinal alignments with a lordotic cervical spine showed significantly greater absolute average values of T1 slope, total thoracic kyphosis, and lower thoracic kyphosis for both the 20\ub0 and 25\ub0 seat back angles. For automotive seating postures, the gender difference in spinal alignment was almost straight cervical and less-kyphotic thoracic spine for the female subjects and lordotic cervical and more pronounced kyphotic thoracic spine for the male subjects. The most prominent influence of seatback inclination appeared in Total thoracic kyphosis, with increased angles for 25\ub0 seat back, 8.0\ub0 greater in spinal alignments with a lordotic cervical spine, 3.2\ub0 greater in spinal alignments with a kyphotic cervical spine. The difference in total thoracic kyphosis between the two seatback angles and between the seating posture with the 20\ub0 seat back angle and the standing posture was greater for spinal alignments with a lordotic cervical spine than for spinal alignments with a kyphotic cervical spine. The female subjects in this study had a tendency toward the kyphotic cervical spine. Some of the differences between average gender-specific spinal alignments may be explained by the findings observed in the differences between spinal alignments with a lordotic and kyphotic cervical spine

Biofidelity Implications for Developing Design Concept of Female Physical Test Device based on Human Body Simulations

AbstractIntroductionStudies have shown that most of the whiplash injuries are caused by the rear crashes [1,2], and therefore, there is a need for evaluate restraint systems in this specific type of crash. Currently, BioRID is the most biofidelic Anthropometric Test Device (ATD) for rear impacts and it represents an average male anthropometry [3]. However, epidemiological data has shown that females have a higher risk for whiplash injury compared to males [4]. Presently, there is only a prototype female ATD developed for evaluating whiplash injuries with respect to rear impacts [5]. This study was conducted to evaluate biofidelity of design changes in a Finite Element (FE) human body model of an average sized female with objective to provide a design concept of a physical test device. The results of this study could provide guidance for development of the future ATDs.MethodsThe open source ViVA 50th percentile female model [4] was adopted as a baseline model for this study. The FE simulations were conducted with the solver LS-DYNA (LSTC, Livermore,CA). Simplifications were made to the spinal column. Design-1 had a rigid thoracolumbar spine (T1-L5), and Design-2 had a rigid thoracic spine (T1-T12). Output were parameters such as cervical spine curvatures and kinematics. A rear impact was simulated with the models positioned on a simplified rigid seat [4].ResultsDesign-1 and 2 both had almost similar head kinematics. The cervical kinematics changed when the inferior spinal portions were made rigid. After positioning the models with gravity, the initial cervical curvatures were different with more pronounced lordosis and superior location of T1 in the Design-1 and Design-2.DiscussionThis study indicates the importance of thoraco-lumbar spinal curvature and stiffness on the cervical kinematics in rear impacts. In the design with rigid thoraco-lumbar spine, the cervical joints will be subjected to larger flexion-extension motions with slightly difference in head kinematics. This study is a first attempt to identify simplifications of the spine for implementation in a physical model with maintained main characteristics that allow the model to identify injury protective performances of the seat. Simulations with different seat models will be needed to ensure that the simplifications do not affect the ability of the model to distinguish between such characteristics of a seat.AcknowledgementsThis study was funded by the Swedish Governmental Agency for Innovation Systems (VINNOVA) and was carried out at SAFER.References1.Galasko,CSB.,et al.,(1993).Injury,Vol.24.No.3pp.155-1572.Krafft,M.,(1998).IRCOBI.,pp.235-2483.Davidsson,J.,et al.,(2000)J.CrashPrevInjControl,Vol.2(3) pp.202–2204. 6sth,J.,et al.,(2017).IRCOBI.,pp.443-4665.Carlsson,A.,et al.,(2012).IRCOBI.,pp.249–26