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Technical Paper

A New Approach to Occupant Simulation Through the Coupling of PC-Crash and MADYMO

During recent years the accident simulation program PC-Crash was developed. This software simulates vehicle movement before, during and after the impact, using 3D vehicle and scene models. ...A new interface has been developed between MADYMO® and PC-Crash so that, after the reconstruction of an accident, only a few additional parameters regarding restraint system, seat and occupant must be defined. ...A new interface has been developed between MADYMO® and PC-Crash so that, after the reconstruction of an accident, only a few additional parameters regarding restraint system, seat and occupant must be defined. PC-Crash then creates all necessary input files for MADYMO® and starts the occupant simulation.
Technical Paper

Effective Numerical Simulation Tool for Real-World Rollover Accidents by Combining PC-Crash and FEA

In this work, we focused on the trip-over type, which occurs most frequently, and performed simulations to reproduce real-world rollover accidents by combining PC-Crash and FEA. At first, using a simplified full car model, sufficient conditions, such as additional velocity, required for a curb trip-over accident to occur, were derived from energy balance concept based on the same principle as critical sliding velocity (CSV) criterion. ...Based on rigid body dynamics, PC-Crash software was chosen to make an accident reconstruction analysis of some selected cases chosen from an accident database (NASS-CDS). ...The output of this PC-crash simulation was then used as the initial input conditions (i.e., speed, deceleration, etc.) of a detailed finite element analysis.
Technical Paper

Soil Trip Rollover Simulation and Occupant Kinematics in Real World Accident

In this work, we focused on the trip-over type, which occurs most frequently, and performed simulations to reproduce real-world rollover accidents by combining PC-Crash and FEA. Soil trip-over simulation was carried out based on real world accidents. Based on rigid body dynamics, PC-Crash software was chosen to make an accident reconstruction analysis of some selected cases chosen from an accident database (NASS-CDS). ...Based on rigid body dynamics, PC-Crash software was chosen to make an accident reconstruction analysis of some selected cases chosen from an accident database (NASS-CDS). ...The output of this PC-crash simulation was then used as the initial input conditions (i.e., speed, deceleration, etc.) of a detailed finite element analysis.
Technical Paper


All of them are analysed in-depth and reconstructed with PC-Crash. The effects of the frontal structure of the vehicles and several active systems, such as BAS and Pedestrian Detection Systems, are evaluated. ...The paper includes the description of the methodology followed for a sample of approximately 140 pedestrian urban accidents in three cities in Spain (Madrid, Barcelona and Zaragoza) and the corresponding reconstructions done with PC-Crash. Then, a methodology to simulate the passive and active improvements (including pedestrian friendly structure, BAS and pedestrian detection system) is defined and applied to all the sampled accidents.
Technical Paper

Field Effectiveness Calculation of Integrated Safety Systems

The vehicle dynamics of all scenarios from the database will be simulated in PC-Crash, an accident-reconstruction software. Since the brake assist is obligatory from 2012 on, the system and its effect on each single accident scenario will be modeled.
Technical Paper

Simulation and Testing of a Suite of Field Relevant Rollovers

Automotive rollover is a complex mechanical phenomenon. In order to understand the mechanism of rollover and develop any potential countermeasures for occupant protection, efficient and repeatable laboratory tests are necessary. However, these tests are not well understood and are still an active area of research interest. It is not always easy or intuitive to estimate the necessary initial and boundary conditions for such tests to assure repeatability. This task can be even more challenging when rollover is a second or third event (e.g. frontal impact followed by a rollover). In addition, often vehicle and occupant kinematics need to be estimated a-priori, first for the safe operation of the crew and equipment safety, and second for capturing and recording the event. It is important to achieve the required vehicle kinematics in an efficient manner and thus reduce repetitive tests. Mathematical modeling of the phenomenon can greatly assist in understanding such kinematics.
Technical Paper

Development of CAE Methodology for Rollover Sensing Algorithm

The Rollover CAE model is developed for Rollover sensing algorithm in this paper. By using suggested CAE model, it is possible to make sensing data of rollover test matrix and these data can be used for calibration of rollover sensing algorithm. Developed vehicle model consists of three parts: a vehicle parts, an occupant parts and a ground boundary conditions. The vehicle parts include detailed suspension model and FE structure model. The occupant parts include ATD (anthropomorphic test device) male dummy and restraint systems: Curtain Airbag and Seat-Belt. We find analytical value of the suspension model through correlation with vehicle drop test, simulate this model under the conditions of untripped (Embankment, Corkscrew) and tripped (Curb-Trip, Soil-Trip) rollover scenarios. Comparison of the simulation and experimental data shows that the simulation results of suggested CAE model can be substituted for the experimental ones in calibration of rollover sensing algorithm.

Rollover Testing Methods

The scope of this document is to provide an overview of the techniques found in the published literature for rollover testing and rollover crashworthiness evaluation at the vehicle and component levels. It is not a comprehensive literature review, but rather illustrates the techniques that are in use or have been used to evaluate rollover crashworthiness-related issues.
Technical Paper

Challenges in Simulation and Sensor Development for Occupant Protection in Rollover Accidents

Automotive occupant safety continues to evolve. At present this area has gathered a strong consumer interest which the vehicle manufacturers are tapping into with the introduction of many new safety technologies. Initially, individual passive devices and features such as seatbelts, knee- bolsters, structural crush zones, airbags etc., were developed for to help save lives and minimize injuries in accidents. Over the years, preventive measures such as improving visibility, headlights, windshield wipers, tire traction etc., were deployed to help reduce the probability of getting into an accident. With tremendous new research and improvements in electronics, we are at the stage of helping to actively avoid accidents in certain situations as well as providing increased protection to vehicle occupants and pedestrians.
Technical Paper

Essential Considerations in Delta-V Determination

While Delta-V has been one of the most used indicators of accident severity for vehicle occupants, its actual determination remains a mystery to many who refer to it and use it. Delta-V is a term of art applied to a rapid change in vehicle velocity caused by impact forces during a collision. The Delta-V is associated with the high decelerations, which cause it and are applied to the occupants through restraint systems and collisions with the interior of the vehicle. This paper will serve as a primer for those new to the subject and a review for those who are familiar with the subject. Previous works by the authors will be referenced and other pertinent literature and data sources will be discussed. The analytical methods and test data used to calculate Delta-V will be presented and the relationship between Delta-V and other measures of impact severity, such as Barrier Equivalent Velocity and Energy Equivalent Speed will be discussed. The use of air bag sensor data will be included.
Technical Paper


The most important topic in the field of passive safety of buses and coaches nowadays is the future compulsory use of seat belts. The objective of the study performed by IDIADA AUTOMOTIVE TECHNOLOGY SA and CENTRO ZARAGOZA is to make an important contribution to the existing technical data about this subject. This paper is based on the in-depth analysis of recent road traffic accidents where buses were involved. The first step is the accident reconstruction. A complete injury report including description and causes of occupant injuries is the basis for the correlation of a computer simulation model. Experience in the development of coach seats equipped with seat belts enables the preparation of a comparative model. The hypothesis that the consequences of the accident could have been less severe if the occupants of the bus had worn a seat belt can be evaluated. The conclusions will help the legislators make the right decision.
Technical Paper

Modeling the Effects of Seat Belt Pretensioners on Occupant Kinematics During Rollover

The results of a number of previous studies have demonstrated that seat-belted occupants can undergo significant upward and outward excursion during the airborne phase of vehicular rollover, which may place the occupant at risk for injury during subsequent ground contacts. Furthermore, testing using human volunteers, ATDs, and cadavers has shown that increasing tension in the restraint system prior to a rollover event may be of value for reducing occupant displacement. On this basis, it may be argued that pretensioning the restraint system, utilizing technology developed and installed primarily for improving injury outcome in frontal impacts, may modify restrained occupant injury potential during rollover accidents. However, the capacity of current pretensioner designs to positively impact the motion of a restrained occupant during rollover remains unclear.
Technical Paper

Comparisons of Devices for Measuring Acceleration vs. Time in Braking Tests

The coefficient of friction between a vehicle's tires and the roadway is a key parameter in any accident reconstruction. With the proliferation of vehicle dynamics software, it is often important to have more details regarding the tires interaction with the road than simply the average deceleration rate. Devices which can provide the peak friction as the braking develops, along with the average deceleration during the fully developed sliding phase, are necessary. There are now products widely available to the accident reconstruction market which provides these parameters as well as detailed acceleration vs. time curves. The following products capable of providing these results were tested: Accelerex, Vericom VC3000, and two general purpose accelerometers made by Silicon Designs and Dimension Engineering. Tests were conducted on wet and dry asphalt surfaces using a variety of passenger vehicles and transit buses which confirmed the agreement between these devices.
Technical Paper

A Pilot Study at National Highway-8 for On-Site Crash Data Collection and In-Depth Investigation in India

The importance of on-site, in-depth accident research studies has been recognized internationally especially in developed countries. In order to address problems related to road safety, it is important to understand the epidemiology and causation of crashes. For this an in-depth investigation of the crash site, vehicles involved and injury details is required. Detailed crash information helps in analysing the events leading to crash and developing safety measures and/or intervention to reduce crashes. In order to pilot such an activity in India, an in-depth accident data collection activity had been carried out on national highway connecting Delhi to Jaipur (NH-8) for a duration of over a year by a joint team of IIT-Delhi and NATRiP. A total of 1220 road traffic accidents (RTA) notifications were received by the team, of which 186 cases were attended and detailed data was collected in a pre-decided format.
Technical Paper

Design and Evaluation of an Affordable Seatbelt Retrofit for Motor Coach Occupant Safety

Prevention of passenger ejection from motor coach seats in the case of rollover and frontal crashes is critical for minimizing fatalities and injuries. This paper proposes a novel concept of affordably retrofitting 3-point seatbelts to protect passengers during these significant crash scenarios. Currently, the available options involve replacement of either the entire fleet, which takes time to avoid extremely high costs, or all seats with new seats that have seatbelts which is still expensive. Alternatively, this paper presents the development of an innovative product that can be installed in seat belt-ready bus structures at a fraction of the cost. The efficacy of the design is studied using finite element analysis (FEA) to meet Federal Motor Vehicle Safety Standards (FMVSS) 210 standards for conditions involved in frontal and side impacts.
Technical Paper

Effectiveness of Side-Airbags for Front Struckside Belted Car Occupants in Lateral Impact Conditions - An In-Depth-Analysis by GIDAS1

Accident documentations on GIDAS (German In-Depth-Accident Study) from 1999 to 2005 are used for this study dealing with the effectiveness of the side airbag protection for car occupants. An analysis of real world accidents was carried out by ARU-MUH (Accident Research Unit - Medical University Hannover). The data were collected based on the spot documentation in time after an accident event. Based on the accident sampling process, the results of this study are representative for the German traffic accident situation. In order to determine the influence and the effectiveness of airbags, only those accident configurations with comparable conditions on impact direction are used for the study, therefore only cases with impact to the compartment, a delta-v-range 5 to 50 km/h and for struckside seated belted occupants were selected.
Technical Paper

The Accident Research Unit Hannover as Example for Importance and Benefit of Existing In Depth Investigations

The In-Depth Investigations of the Accident Research Unit Hannover (Germany), which have been carried out since 1973 are described in the paper. The importance of the detailed analysis consists in the method, in the statistical approach and the continuous data collection over the years. The government as well as industrial manufacturers use this data. Since 1985 a statistical procedure including a mathematical weighting procedure has been applied. About 1000 cases per year are collected. In the paper, principal aspects in the technique of data collection, definitions of variables and possibilities of data usage are described. The limitations of in-depth investigations are discussed in principle, and demands for a worldwide level are pointed out.
Journal Article

A Bayesian Approach to Cross-Validation in Pedestrian Accident Reconstruction

In statistical modeling, cross-validation refers to the practice of fitting a model with part of the available data, and then using predictions of the unused data to test and improve the fitted model. In accident reconstruction, cross-validation is possible when two different measurements can be used to estimate the same accident feature, such as when measured skidmark length and pedestrian throw distance each provide an estimate of impact speed. In this case a Bayesian cross-validation can be carried out by (1) using one measurement and Bayes theorem to compute a posterior distribution for the impact speed, (2) using this posterior distribution to compute a predictive distribution for the second measurement, and then (3) comparing the actual second measurement to this predictive distribution. An actual measurement falling in an extreme tail of the predictive distribution suggests a weakness in the assumptions governing the reconstruction.
Journal Article

Injury Rates for Older and Younger Belted Drivers in Traffic Accidents

This paper describes the correlation of a person's age to the risk of injury occurrence and the corresponding injury severity in traffic accidents. A representative sample of belted drivers was analyzed by using data from the German In-Depth-Accident Study (GIDAS) to investigate the influence of age on injury severity and special injuries to different body regions. The study focused on two age groups: 17-30 year old (younger drivers) and older drivers 50 year old and older (50+). The injury risk was described as a function of delta-v and injury risk curves based on Abbreviated Injury Scale (AIS). Furthermore, individual parameters like age and body mass index (BMI) as well as age and mass of the vehicle were considered. The statistical analysis was carried out using descriptive and multivariate statistics. This paper presents an overview of injury patterns of belted drivers and the probability of these drivers being injured in different accident scenarios.