The influence of car passengers’ sitting postures in intersection crashes

Car passengers are frequently sitting in non-nominal postures and are able to perform a wide range of activities since they are not limited by tasks related to vehicle control, contrary to drivers. The anticipated introduction of Autonomous Driven vehicles could allow “drivers” to adopt similar postures and being involved in the same activities as passengers, allowing them a similar set of non-nominal postures. Therefore, the need to investigate the effects of non-nominal occupant sitting postures during relevant car crash events is becoming increasingly important. This study aims to investigate the effect of different postures of passengers in the front seat of a car on kinematic and kinetic responses during intersection crashes. A Human Body Model (HBM) was positioned in a numerical model of the front passenger seat of a midsize Sports Utility Vehicle (SUV) in a total of 35 postures, including variations to the lower and upper extremities, torso, and head postures. Three crash configurations, representative of predicted urban intersection crashes, were assessed in a simulation study; two side impacts, a near-side and a far-side, respectively, and a frontal impact. The occupant kinematics and internal loads were analyzed, and any deviation between the nominal and altered posture responses were quantified using cross-correlation of signals to highlight the most notable variations. Posture changes to the lower extremities had the largest overall influence on the lower extremities, pelvis, and whole-body responses for all crash configurations. In the frontal impact, crossing the legs allowed for the highest pelvis excursions and rotations, which affected the whole-body response the most. In the two side-impacts, leaning the torso in the coronal plane affected the torso and head kinematics by changing the interaction with the vehicle\u27s interior. Additionally, in far-side impacts supporting the upper extremity on the center console resulted in increased torso excursions. Moreover, the response of the upper extremities was consistently sensitive to posture variations of all body regions

Trygghet och delaktighet på daghem : Idéer till en verksamhetsgudie för Dagisfred

Syftet med det här examensarbetet är att samla idéer till en verksamhetsguide för Dagisfred. Dagisfred är ett projekt startat av Folkhälsans förbund rf och under år 2016 utvecklar Folkhälsan konceptet Dagisfred och samarbetar med studerande vid yrkeshögskolan Novia. Målet med Dagisfred är att ytterligare stärka daghemmens arbete med respekt, delaktighet och trygghet. De mest relevanta begreppen i detta arbete är delaktighet och inflytande. För att få fram idéer till verksamhetsguiden har besök till ett samarbetsdaghem gjorts, och för att få fram barns och pedagogers tankar och åsikter har Folkhälsan utvecklat två verktyg som har använts för att genomföra detta. En Dialogduk för daghemmets personal och Spelet för Dagisfred för barnen, som skribenter från detta examensarbete varit med och dokumenterat användningen av. Efter att resultaten från användningen av dessa verktyg och examensarbetets teori har analyserats, har skribenterna arbetat fram idéer som kommer att sammanställas till en verksamhetsguide. Som slutsats efter användningen av dessa verktyg kan skribenterna konstatera att de fungerar bra för att ta till vara barnens och personalens tankar, åsikter och idéer. Verksamhetguiden kommer att stöda daghem att implementera Dagisfred på den egna enheten.Tämän opinnäytetyön tavoitteena on keksiä ideoita Folkhälsanin aloittamaan hankkeeseen, jonka tavoitteena on luoda päiväkotirauhaa käsittelevä toimintaopas. Toimintaoppaan tavoitteena on vahvistaa lasten osallisuutta päiväkodissa, eli huomioida heidän ajatuksiaan ja toiveitaan päiväkotitoimintaan liittyen sekä huomioida lasten turvallinen kasvuympäristö. Tärkeimpänä käsiteenä tässä opinnäytetyössä on lasten osallisuus. Ideoiden saamiseksi osa kirjoittajista on vieraillut yhteistyöpäiväkodissa. Jotta lasten ja aikuisten ajatukset ja mielipiteet on saatu selville, on Folkhälsan kehittänyt kaksi työkalua tätä selvitystyötä varten.. Työkalut ovat Dialogduk päiväkodin työntekijöille ja Spelet för Dagisfred lapsille. Näiden pelien avulla saatiin selville lasten ja aikuisten ideoita ja ajatuksia päiväkotirauhasta, joiden perusteella kirjoittajat keräsivät ideat toimintaoppaaksi. Kirjoittajien mielestä työkalut, Dialogduken ja Spelet för Dagisfred, toimivat hyvin ja niiden avulla saadaan pedagogien ja lasten ajatuksia ja mielipiteitä selville. Tämän oppaan on tarkoitus olla avuksi päiväkodeille, jotka voivat sen avulla alkaa kehittää Päiväkotirauhaa omassa päiväkodissaan.The purpose of this bachelor’s thesis is to collect ideas for an activity guide for the project Dagisfred. The project was initiated by Folkhälsans förbund r.f. and during 2016 Folkhälsan is developing the concept of Dagisfred by cooperating with students from Novia Univeristy of Applied Sciences. The goal of the project is to further strengthen nurseries work with respect, participation and safety. The main focus of this bachelor’s thesis was childrens participation and influence in nurseries. Ideas for the activity guide are collected by obtaining children’s and educators thoughts and opinions about Dagisfred. To be able to do this Folkhälsan has developed two instruments, Spelet för Dagisfred and Dialogduken. Spelet for Dagisfred is a game for children and Dialogduken is for the staff. The students have documented the use of these instruments at the nursery. The result from these documentations has then been analyzed. Based on the analysis of the result and the bachelor’s thesis theory the students have developed ideas that will be compiled to an activity guide. The results show that the instruments work well in use of collecting thoughts and opinions from the children as well as educators. The activity guide will support nurseries to achieve Dagisfred

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

Multi-Scale Validation of a Rib Fracture Prediction Method for Human Body Models

A multi-scale validation of the capability of the SAFER human body model (v9) to predict the risk for an occupant to sustain two or more rib fractures in vehicle crashes was carried out. The rib fracture risk was evaluated by means of a probabilistic rib fracture prediction method. A variety of loading conditions was evaluated, from published lab tests with post mortem human subjects (PMHS) to detailed accident reconstructions and population-based reconstructions. The PMHS load cases were table-top, impactor and sled tests. The detailed accident reconstructions included 20 occupants involved in real-world crashes. For the population-based reconstructions more than 100 simulations with a generic vehicle interior model were carried out. Parameters regarding both the generic model and the occupant were varied in the population-based simulations. The predicted risk for an occupant to sustain two or more rib fractures was evaluated for the PMHS sled reconstructions as well as for the detailed and population-based reconstructions. The predicted 2 or more rib fracture risk was compared to the actual number of fractured ribs sustained by the PMHS and the occupants. Generally, two or more fractured ribs observed in the PMHS tests, the vehicle crashes and NASS data were successfully predicted with the model

Safety of children in cars: A review of biomechanical aspects and human body models

The protection of children in motor vehicle crashes has improved since the introduction of child restraint systems. However, motor vehicle crashes remain one of the top leading causes of death for children. Today, computer-aided engineering is an essential part of vehicle development and it is anticipated that safety assessments will increasingly rely on simulations. Therefore, this study presents a review of important biomechanical aspects for the safety of children in cars, including child human body models, for scenarios ranging from on-road driving, emergency maneuvers, and pre-crash events to crash loading. The review is divided into four parts: Crash safety, On-road driving for forward facing children, Numerical whole body models, and Discussion and future outlook.The first two parts provide ample references and a state-of-the-art description of important biomechanical aspects for the safety of children in cars. That children are not small adults has been known for decades and has been considered during the development of current restraints that protect the child in the crash phase. The head, neck, thorax, and pelvis are body areas where development with age changes the biomechanics and the interaction with restraint systems. The rear facing child seat distributes the crash load over a large area of the body and has proved to be a very efficient means of reducing child injuries and fatalities. Children up to age 4. years need to be seated rearward facing for optimal protection, mainly because of the proportionally large head, neck anthropometry and cartilaginous pelvis. Children aged 4 up to 12. years should use a belt positioning booster together with the vehicle seat belt to ensure good protection, as the pelvis is not fully developed and because of the smaller size of these children compared to adults. On-road driving studies have illustrated that children frequently change seated posture and may choose slouched positions that are poor for lap belt interaction if seated directly on the rear seat. Emergency maneuvers with volunteers illustrate that pre-crash loading forces forward-facing children into involuntary postures with large head displacements, having potential influence on the risk of head impact. Children, similar to adults, benefit from the safety systems offered in the vehicle. By providing child adaptability of the vehicle, such as integrated booster cushions, the child-restraint interaction can be further optimized. An example of this is the significant reduction of lap belt misuse when using integrated boosters, due to the simplified and natural positioning of the lap belt in close contact with the pelvis. The research presented in this review illustrates that there is a need for enhanced tools, such as child human body models, to take into account the requirements of children of different ages and sizes in the development of countermeasures.To study how children interact with restraints during on-road driving and during pre- and in-crash events, numerical child models implementing age-specific anthropometric features will be essential. The review of human whole body models covers multi body models (age 1.5 to 15. years) and finite element models (ages 3, 6, and 10. years). All reviewed child models are developed for crash scenarios. The only finite element models to implement age dependent anthropometry details for the spine and pelvis were a 3. year-old model and an upcoming 10. year-old model. One ongoing project is implementing active muscles response in a 6. year-old multi body model to study pre-crash scenarios. These active models are suitable for the next important step in providing the automotive industry with adequate tools for development and assessment of future restraint systems in the full sequence of events from pre- to in-crash. Document type: Articl

A method for predicting crash configurations using counterfactual simulations and real-world data

Traffic safety technologies revolve around two principle ideas; crash avoidance and injury mitigation for inevitable crashes. The development of relevant vehicle injury mitigating technologies should consider the interaction of those two technologies, ensuring that the inevitable crashes can be adequately managed by the occupant and vulnerable road user (VRU) protection systems. A step towards that is the accurate description of the expected crashes remaining when crash-avoiding technologies are available in vehicles. With the overall objective of facilitating the assessment of future traffic safety, this study develops a method for predicting crash configurations when introducing crash-avoiding countermeasures. The predicted crash configurations are one important factor for prioritizing the evaluation and development of future occupant and VRU protection systems. By using real-world traffic accident data to form the baseline and performing counterfactual model-in-the-loop (MIL) pre-crash simulations, the change in traffic situations (vehicle crashes) provided by vehicles with crash-avoiding technologies can be predicted. The method is built on a novel crash configuration definition, which supports further analysis of the in-crash phase. By clustering and grouping the remaining crashes, a limited number of crash configurations can be identified, still representing and covering the real-world variation. The developed method was applied using Swedish national- and in-depth accident data related to urban intersections and highway driving, and a conceptual Autonomous Emergency Braking system (AEB) computational model. Based on national crash data analysis, the conflict situations Same-Direction rear-end frontal (SD-ref) representing 53 % of highway vehicle-to-vehicle (v2v) crashes, and Straight Crossing Path (SCP) with 21 % of urban v2v intersection crashes were selected for this study. Pre-crash baselines, for SD-ref (n = 1010) and SCP (n = 4814), were prepared based on in-depth accident data and variations of these. Pre-crash simulations identified the crashes not avoided by the conceptual AEB, and the clustering of these revealed 5 and 52 representative crash configurations for the highway SD-ref and urban intersection SCP conflict situations, respectively, to be used in future crashworthiness studies. The results demonstrated a feasible way of identifying, in a predictive way, relevant crash configurations for in-crash testing of injury prevention capabilities

Validation of the SAFER Human Body Model Kinematics in Far-Side Impacts

Human Body Models are essential for real-world occupant protection assessment. With the overall purpose to create a robust human body model which is biofidelic in a variety of crash situations, this study aims to evaluate the biofidelity of the SAFER human body model in far-side impacts. The pelvis, torso and the upper and lower extremities of the SAFER human body model were updated. In addition, the shoulder area was updated for improved shoulder belt interaction in far-side impacts. The model was validated using kinematic corridors based on published human subject test data from two far-side impact set-ups, one simplified and one vehicle-based. The simplified far-side set-up included six configurations with different parameter settings, and the vehicle-based included two configurations: with and without far-side airbag, respectively. The updated SAFER HBM was robust and in general the model predicted the published human subject responses (kinematic CORA score > 0.65) for all configurations in both test set-ups. An exception was a 90 degree far-side impact with the D-ring in the forward position, in the simplified set-up. Here the model could not predict the shoulder belt retention, resulting in a low CORA score. Based on the overall results, the model is considered valid to be used for assessment of far-side impact countermeasures

Personalization of human body models and beyond via image registration

Finite element human body models (HBMs) are becoming increasingly important numerical tools for traffic safety. Developing a validated and reliable HBM from the start requires integrated efforts and continues to be a challenging task. Mesh morphing is an efficient technique to generate personalized HBMs accounting for individual anatomy once a baseline model has been developed. This study presents a new image registration–based mesh morphing method to generate personalized HBMs. The method is demonstrated by morphing four baseline HBMs (SAFER, THUMS, and VIVA+ in both seated and standing postures) into ten subjects with varying heights, body mass indices (BMIs), and sex. The resulting personalized HBMs show comparable element quality to the baseline models. This method enables the comparison of HBMs by morphing them into the same subject, eliminating geometric differences. The method also shows superior geometry correction capabilities, which facilitates converting a seated HBM to a standing one, combined with additional positioning tools. Furthermore, this method can be extended to personalize other models, and the feasibility of morphing vehicle models has been illustrated. In conclusion, this new image registration–based mesh morphing method allows rapid and robust personalization of HBMs, facilitating personalized simulations

REAR SEAT SAFETY IN FRONTAL TO SIDE IMPACTS – FOCUSING ON OCCUPANTS FROM 3YRS TO SMALL ADULTS

ABSTRACT This study presents a broad comprehensive research effort that combines expertise from industry and academia and uses various methodologies with applied research directed towards countermeasures. The project includes real world crash data analysis, real world driving studies and crash testing and simulations, aiming at enhancing the safety of forward facing child occupants (aged 3y to small adults) in the rear seat during frontal to side impacts. The real world crash data analyses of properly restrained children originate from European as well as US data. Frontal and side impact crash tests are analyzed using different sizes of crash test dummies in different sitting postures. Side impact parameter studies using FE-models are run. The sitting posture and behavior of 12 children are monitored while riding in the rear seat. Also, the body kinematics and belt position during actual braking and turning maneuvers are studied for 16 rear seat child occupants and for various child dummies. Real world crash data indicates that several of the injured children in frontal impacts, despite being properly restrained, impacted the vehicle interior structure with their head/face resulting in serious injury. This was attributed to oblique crashes, pre-crash vehicle maneuvers or high crash severity. Crash tests confirm the importance of proper initial belt-fit for best protection. The crash tests also highlight the difficulty in obtaining the real world kinematics and head impact locations using existing crashtest dummies and test procedures. The side impact parameter studies indicate that the vehicle’s occupant protection systems, such as airbags and seat belt pretensioners, play an important role in protecting children as well. The results from the on-road driving studies illustrate the variation of sitting postures during riding in the rear seat giving valuable input to the effects of the restraint systems and to how representative the standardized dummy seating positioning procedures are. The results from the maneuver driving studies illustrate the importance of understanding the kinematics of a child relative to the seat belt in a real world maneuver situation. Real world safety of rear seat occupants, especially children, involves evaluation of protection beyond standard crash testing scenarios in frontal and side impact conditions. This project explores the complete context of rear seat protection in impact situations ranging from front to side and directions in between highlighting the importance of pre-crash posture and behavior. This research project at SAFER (Vehicle and Traffic Safety Centre at Chalmers), where researchers from the industry and universities cooperate with the aim to further improve safety for children (from 3y) to small adults in the rear seat, speeds up the process to safety implementation due to the interaction between academic and industrial researchers