Jac Wismans

The Occupant Response to Autonomous Braking: A Modeling Approach That Accounts for Active Musculature

Objective: The aim of this study is to model occupant kinematics in an autonomous braking event by using a finite element (FE) human body model (HBM) with active muscles as a step toward HBMs that can be used for injury prediction in integrated precrash and crash simulations. Methods: Trunk and neck musculature was added to an existing FE HBM. Active muscle responses were achieved using a simplified implementation of 3 feedback controllers for head angle, neck angle, and angle of the lumbar spine. The HBM was compared with volunteer responses in sled tests with 10 ms−2 deceleration over 0.2 s and in 1.4-s autonomous braking interventions with a peak deceleration of 6.7 ms−2. Results: The HBM captures the characteristics of the kinematics of volunteers in sled tests. Peak forward displacements have the same timing as for the volunteers, and lumbar muscle activation timing matches data from one of the volunteers. The responses of volunteers in autonomous braking interventions are mainly small head rotations and translational motions. This is captured by the HBM controller objective, which is to maintain the initial angular positions. The HBM response with active muscles is within ±1 standard deviation of the average volunteer response with respect to head displacements and angular rotation. Conclusions: With the implementation of feedback control of active musculature in an FE HBM it is possible to model the occupant response to autonomous braking interventions. The lumbar controller is important for the simulations of lap belt–restrained occupants; it is less important for the kinematics of occupants with a modern 3-point seat belt. Increasing head and neck controller gains provides a better correlation for head rotation, whereas it reduces the vertical head displacement and introduces oscillations.

Neck Forces and Moments and Head Accelerations in Side Impact

Objectives: Although side-impact sled studies have investigated chest, abdomen, and pelvic injury mechanics, determination of head accelerations and the associated neck forces and moments is very limited. The purpose of the present study was therefore to determine the temporal forces and moments at the upper neck region and head angular accelerations and angular velocities using postmortem human subjects (PMHS). Methods: Anthropometric data and X-rays were obtained, and the specimens were positioned upright on a custom-designed seat, rigidly fixed to the platform of the sled. PMHS were seated facing forward with the Frankfort plane horizontal, and legs were stretched parallel to the mid-sagittal plane. The normal curvature and alignment of the dorsal spine were maintained without initial torso rotation. A pyramid-shaped nine-accelerometer package was secured to the parietal-temporal region of the head. The test matrix consisted of groups A and B, representing the fully restrained torso condition, and groups C and D, representing the three-point belt–restrained torso condition. The change in velocity was 12.4 m/s for groups A and C, 17.9 m/s for group B, and 8.7 m/s for group D tests. Two specimens were tested in each group. Injuries were scored based on the Abbreviated Injury Scale. The head mass, center of gravity, and moment of inertia were determined for each specimen. Head accelerations and upper neck forces and moments were determined before head contact. Results: Neck forces and moments and head angular accelerations and angular velocities are presented on a specimen-by-specimen basis. In addition, a summary of peak magnitudes of biomechanical data is provided because of their potential in serving as injury reference values characterizing head-neck biomechanics in side impacts. Though no skull fractures occurred, AIS 0 to 3 neck traumas were dependent on the impact velocity and restraint condition. Conclusions: Because specimen-specific head center of gravity and mass moment of inertia were determined, and a suitable instrumentation system was used for data collection and analysis, head angular accelerations and neck forces and moments determined in the present study can be used with confidence to advance impact biomechanics research. Although the sample size is limited in each group, results from these tests serve as a fundamental data set to validate finite element models and evaluate the performance and biofidelity of federalized and prototype side-impact dummies with a focus on head-neck biomechanics.

Commentary: Status of road safety in Asia

ABSTRACT Objectives: The objective of this article is to assess the status of road safety in Asia and present accident and injury prevention strategies based on global road safety improvement experiences and discuss the way forward by indicating opportunities and countermeasures that could be implemented to achieve a new level of safety in Asia. Methods: This study provides a review and analyses of data in the literature, including from the World Health Organization (WHO) and World Bank, and a review of lessons learned from best practices in high-income countries. In addition, an estimation of costs due to road transport injuries in Asia and review of future trends in road transport is provided. Results: Data on the global and Asian road safety problem and status of prevention strategies in Asia as well as recommendations for future actions are discussed. The total number of deaths due to road accidents in the 24 Asian countries, encompassing 56% of the total world population, is 750,000 per year (statistics 2010). The total number of injuries is more than 50 million, of which 12% are hospital admissions. The loss to the economy in the 24 Asian countries is estimated to around US

Human rib response to different restraint systems in frontal impacts: a study using a human body model

800 billion or 3.6% of the gross domestic product (GDP). Conclusions: This article clearly shows that road safety is causing large problems and high costs in Asia, with an enormous impact on the well-being of people, economy, and productivity. In many Asian low- and middle-income countries, the yearly number of fatalities and injuries is increasing. Vulnerable road users (pedestrians, cyclists, and motorcyclists combined) are particularly at risk. Road safety in Asia should be given rightful attention, including taking powerful, effective actions. This review stresses the need for reliable accident data, because there is considerable underreporting in the official statistics. Reliable accident data are imperative to determine evidence-based intervention strategies and monitor the success of these interventions and analyses. On the other hand, lack of good high-quality accident data should not be an excuse to postpone interventions. There are many opportunities for evidence-based transport safety improvements, including measures concerning the 5 key risk factors: speed, drunk driving, not wearing motorcycle helmets, not wearing seat belts, and not using child restraints in cars, as specified in the Decade of Action for Road Safety 2011–2020. In this commentary, a number of additional measures are proposed that are not covered in the Decade of Action Plan. These new measures include separate roads or lanes for pedestrians and cyclists; helmet wearing for e-bike riders; special attention to elderly persons in public transportation; introduction of emerging collision avoidance technologies, in particular automatic emergency braking (AEB) and alcohol locks; improved truck safety focusing on the other road user (including blind spot detection technology; underride protection at the front, rear, and side; and energy-absorbing fronts); and improvements in motorcycle safety concerning protective clothing, requirements for advanced braking systems, improved visibility of motorcycles by using daytime running lights, and better guardrails.

Scaling head-neck response data and derivation of 5th percentile female side-impact dummy head-neck response requirements in NBDL test conditions

Finite-element human body models (FE-HBMs) can be used to evaluate restraint systems by predicting thoracic injury. The biofidelity assessment of an FE-HBM Total HUman Model for Safety (THUMS) 50th percentile male occupant and the characterisation of its rib response to loads from frontal car crashes are the objectives of this study. The rib-cage mesh of THUMS version 3.0 was refined to improve the shoulder-belt interaction, material properties of lungs and skin modified, and the model biofidelity assessed against tests representative of frontal crashes. The modified THUMS response improved with respect to the baseline model. The modified THUMS was used to analyse the rib loading in frontal impacts. The rib response included shear, torsion and bending in belt and airbag-like load cases. This indicates that a criterion based only on rib anteroposterior compression may not be enough to predict fractures and that a criterion should consider compression, torsion and shear.

APROSYS: Advances in secondary safety research

The head-neck biofidelity of side-impact dummies can be assessed according to the response requirements for the head-neck system based on mid-size male human subjects as published in ISO TR9790. These criteria are largely based on volunteer tests performed at the Naval Biodynamics Laboratory (NBDL) in New Orleans. The first objective of this study is to provide a judgement on the validity of applying the scaling method developed by Irwin, Mertz, Ali, Elhagediab and Moss [Guidelines for assessing the biofidelity of side impact dummies of various sizes and ages. Stapp Car Crash J. 46 (2002)] to the head-neck system. The second objective is to develop additional scaling rules to supplement the rules developed by Irwin et al. (2002), in case the existing scaling method is not valid. In order to come to a judgement on the validity of applying Irwin et al.s scaling method to the head-neck kinematics and dynamics, first a review was performed on Irwins scaling method, gender related differences, and the head-neck anthropometry versus responses of the NBDL volunteers. On the basis of the review an analysis was performed to find scaling rules for the head-neck kinematics and dynamics that are most plausible. From this study it was concluded that the scaling method developed by Irwin et al. to scale the mid-size male response requirements for the NBDL test condition (ISO TR9790 Neck Test 1) to a small female is only valid for the T1 lateral displacement, but not for the other response requirements. The scale factors that were found to be invalid were updated using relationships found in literature on head-neck biomechanics, and relationships found in the NBDL volunteer analysis.

Holistic Approach for Improved Safety Including a Proposal of New Virtual Test Conditions of Small Electric Vehicles

Secondary, or passive, safety includes the most important strategies to reduce the traffic trauma problem. This field concerns the protection of road users when an accident takes place. The current European R&D needs in this field are partially dealt with in a large European co-operative R&D project Advanced Protection Systems (APROSYS) supported by the European Commission under contract number TIP3-CT-2004-506503. The general objective of APROSYS is the development and introduction of critical technologies that improve passive safety for all European road users in the relevant accident types and for the important severities. An important aspect in APROSYS is the integrated approach with primary, or active, safety, the so-called area of integrated safety. In this introduction paper of this special International Journal of Crashworthiness issue, an overview of the project is presented emphasising its ten main achievements.

Integrated Architectures for Third Generation Electric Vehicles: Technical Challenges Meeting Customer Requirements

In the next 20 years the share of small electric vehicles (SEVs) will increase especially in urban areas. SEVs show distinctive design differences compared to traditional vehicles. Thus the consequences of impacts of SEVs with vulnerable road users (VRUs) and other vehicles will be different from traditional collisions. No assessment concerning vehicle safety is defined for vehicles within European L7e category currently. Focus of the elaborated methodology is to define appropriate test scenarios for this vehicle category to be used within a virtual tool chain. A virtual tool chain has to be defined for the realization of a guideline of virtual certification. The derivation and development of new test conditions for SEVs are described and are the main focus of this work. As key methodology a prospective methodical analysis under consideration of future aspects like pre-crash safety systems is applied. The studies show that certain collision types will be reduced in numbers and in average collision severity. Based on the evaluation following tests are proposed. Frontal: oblique (30°), test speed 35 km/h, 1,300kg Mobile Progressive Deformable Barrier (MPDB); Side: 90°, Advanced European Mobile Deformable Barrier (AE-MDB), barrier speed 40 km/h; Pedestrian safety: seven pedestrian impact locations, 2 speed ranges, four different percentiles. The proposed virtual testing procedure has to be based on well validated models and tools, which can be assumed to be available in the future. The focus of the presented work is on SEVs in L7e category, for which no specific, urban area relevant safety regulations are available. Overall occupant and VRU safety of future SEVs will increase significantly, if additionally to the standard crash tests the elaborated tests from the European Union (EU) initiative SafeEV are applied for the design of safety measures within L7e vehicle class.

Comparison of Hybrid III and Human Body Models in Evaluating Thoracic Response for Various Seat Belt and Airbag Loading Conditions

In order to fully exploit new freedom in design and to achieve a significant increase of energy efficiency, the third generation of electric vehicles requires dedicated architectures. The consortium of the joint research project ELVA—Advanced Electric Vehicle Architectures is developing until mid-2013 three detailed vehicle concepts which are intended to not only meet all technical requirements, but especially take customer preferences directly into account. ELVA can be regarded as one of the first European joint projects dealing with the investigation of vehicle architectures for fully electric vehicles. Aiming at series adoption in 2020, a comprehensive forecast of technology options and market requirements has stood at the beginning. This includes particularly the in-depth analysis of customer requirements. They are investigated based on studies and OEM-internal information, but also on a large-scale public customer survey. In the second phase, these requirements need to be brought in line with technology options by innovative architectures focussing on urban electric vehicles. To complement the expertise within the consortium a public design contest is drawn, allowing designers to present their ideas for future urban mobility. Based on an assessment of all ideas and options, three dedicated vehicle concepts are developed in detail, enabling optimisation and assessment of all relevant vehicle features. Technology options (e.g. batteries and electric motors) and customer expectations are still difficult to predict. On the technology side, substantial improvements especially regarding battery capacity, size and weight are expected. Customer requirements however are very much linked to the use-cases current conventional cars are offering, especially when it comes to the desired range. This has a clear impact on future electric vehicles, but cannot be fully predicted yet. ELVA is the first European project which is dedicated to specific vehicle architectures for urban electric vehicles. Especially the incorporation of customer requirements based on a pan-European survey and the public design competition must be emphasized in this context. The ELVA project brings together technical excellence and customer requirements in order to develop the most promising architectures for urban electric vehicles.