Sonstige
Refine
Document Type
- Conference Proceeding (27)
- Book (4)
Has Fulltext
- yes (31) (remove)
Keywords
- Collision (31) (remove)
The paper aims to study the injury risk and kinematics of pedestrians involved in different passenger vehicle collisions. Furthermore, the difference of pedestrian kinematics in the accidents involved minivan and sedan was analyzed. The 18 sample cases of passenger car to pedestrian collisions were selected from the database of In-depth Investigation of Vehicle Accident in Changsha of China (IVAC),of which the 12 pedestrian accidents involved in a minivan impact for each case, and the 6 accidents in a sedan impact for each. The selected cases were reconstructed by using mathematical models of pedestrians and accident vehicles in a multi-body dynamic code MADYMO environment. The logistic regression models of the risks for pedestrian AIS 3+ injuries and fatalities were developed in terms of vehicle impact speed by analyzing the minivan-pedestrian and sedan-pedestrian accidents. The difference of pedestrian kinematics was identified by comparing the results from reconstructed pedestrian accidents between the minivans and sedans collisions. The result shows that there is a significant correlation among the impact speed and the severity of pedestrian injuries. The minivan poses greater risk to pedestrian than sedan at the same impact speed. The kinematics of pedestrian was greatly influenced by vehicle front shape.
This study analyses no.39 cases in which n.41 motorcyclists were fatally injured, or 36% of total motorcycle fatalities in Northern Ireland between 2004 and 2010 (n.114). There were n.17 cases (43.6%) where the actions of another vehicle driver caused the collision, in thirteen of these cases the motorcycles had their lights switched on. The remaining n.22 collisions (56.4%) were due to the actions of the motorcyclist. In the approach to the collision scene, there were n.13 cases (31.7%) in which the approach was a right hand bend and in n.8 (19.5%) cases, the approach was a left hand bend. In the remaining n.18 (43.9%) cases, the approach was a straight road. Of the n.17 (41.4%) motorcycles that slid after falling, n.10 (24.4%) fell onto their right side and the remaining n.7 (17.1%) fell onto their left side. The information from this study identifies primary and contributory causes of motorcycle collisions.
Real world accident reconstruction with the Total Human Model for Safety (THUMS) in Pam-Crash
(2013)
Further improvement of vehicle safety needs detailed analysis of real world accidents. According to GIDAS (German In-Depth Accident Study) most car to car front accidents occur at mid-crash severity. In this range thoracic injuries already occur. In this study a real world frontal crash with mid-crash severity out of the AARU database was reconstructed. The selected car to car accident was reconstructed by AARU by means of pc-crash software in order to get the initial dynamic accident conditions. These initial conditions were used to reconstruct the complete accident in more detail using FE models for the car structure and the occupants. Occupant simulations were performed with FE HIII-dummy models and the THUMS using Pam-Crash code. An initial THUMS validation was performed in order to verify the model-´s biofidelity by means of table-top test simulations. THUMS bone stiffness values were modified to match the real word occupant age. A comparison between driver and passenger restraint system loading was done, as well as an injury prediction comparison between the HIII-dummy model and THUMS response for both cases. Detailed comparison between the HIII-dummy models and THUMS regarding thoracic loading are discussed.
Rollovers continue to be a major source of heavy truck fatalities when compared to other accident modes. Real world rollover accidents are analyzed and two distinct damage patterns are identified. Damage to heavy truck roofs can occur from lateral loading that transitions to vertical roof loading as the vehicle rolls onto its side and then over onto its roof. A second load path can occur when the vehicle has rolled onto its side and furrows into the ground generating large longitudinal friction forces between the roof and ground. A review of the previous literature and various test methodologies are presented. A sled impact test methodology is presented which allows for structural assessment of a heavy truck cab's crashworthiness in both of these loading environments. Two test series are presented using the sled impact test methodology in order to analyze real world truck rollovers using varying impact platen and contact angles. The structural deformation and failure patterns were found to be consistent with damage seen in real world accident vehicles. In each case, a second equivalent truck cab was then reinforced and tested under similar conditions to evaluate the energy management and crush resistance of a stronger cab structure. These structural reinforcements demonstrated a substantial reduction in roof crush and protected the survival space of the occupant compartment. The sled impact test procedure is an effective method for testing the structural performance of a heavy truck cab in a variety of loading scenarios comparable to real world accidents and ascertaining the load and energy load levels in these accident modes.
The sequence of accident events can be classified by three essential phases, the pre-crash-sequence, the crash-sequence and the post-crash-sequence. The level of reliability of the information in the GIDAS-database (German In Depth Accident Study) is provided predominantly on the passive side. The period to evaluate active safety systems begins already in the pre-crash-sequence. The assessment of the potential of sensor- or communication-based active safety systems can only be accomplished by a detailed analysis of the pre-crash-phase. Hence the necessity to analyze the early period of the accident event in detail arises. This is possible with the help of the digital sketches of the accident site and the simulation of the accident by a simulation method of the VUFO GmbH. After simulating the pre-crash scenario it is possible to generate additional and standardized data to describe the pre-crash-sequences of an accident in a very high detail. These data are documented in a second database called the GIDAS Pre-Crash-Matrix (PCM). The PCM contains various tables with all relevant data to reproduce the pre-crash-sequence of traffic accidents from the GIDAS database until 5 seconds before the first collision. This includes parameters to describe the environment data, participant data and motion or dynamic data. This paper explains the creation of the PCM, the simulation itself and the contents and structure of the PCM. With this information of the pre-crash-sequence for various accident scenarios an improved benefit estimation and development of active safety systems can be made possible.
The objective of the study is to measure the risk of pedestrian and bicyclist in urban traffic through an analysis of real-world accident data. The kinematics and injury mechanisms for both pedestrian and bicyclists are investigated to find the correlation of injury risks with injury related parameters. For this purpose, firstly 338 cases are selected as a sample from an IVAC accident database based on the In-depth Investigation of Vehicle Accident in Changsha of China. A statistic measurement of the fatality and serious injury risks with respect to impact speed was carried out by logistic regression analysis. Secondly, 12 pedestrian and 12 bicyclist accidents were further selected for reconstruction with MADYMO program. A comparative analysis was conducted based on the results from accident analysis and computer reconstructions for the injury risk, head impact conditions and dynamic response of pedestrians and bicyclists. The results indicate that bicyclists suffered lower risks of severe injuries and fatalities compared with pedestrians. The risks of AIS 3+ injury and fatality are 50% for pedestrians at impact speeds of 53.2 km/h and 63.3 km/h, respectively, while that for bicyclists at 62.5 km/h and 71.1 km/h, respectively. The findings could have a contribution to get a better understanding of pedestrians" and bicyclists" exposures in urban traffic in China, and provide background knowledge to generate strategies for pedestrian protection.
Since 2005, the motorcycle crash fatalities in the US exceeded 10% of the overall annual traffic fatalities. Consequently, it has become critical to gain in-depth understanding of the factors and characteristics contributing to motorcycle crashes. Unfortunately, there currently exists no database gathering the necessary information for an in-depth analysis of the US motorcycle crashes. So this study utilizes the NASS/CDS database (National Automotive Sampling System, Crashworthiness Data System) in order to gain insights into the patterns and factors leading to a NASS/CDS motorcycle crash, from 1997 to 2007. NASS/CDS samples about 5,000 passenger car tow-away crashes per year. Each case includes photographs and detailed data on crash and pre-crash characteristics, vehicle types, trajectories, types of impact, and other pertinent roadway and crash scene information, allowing an in-depth investigation of the crash mechanisms. However, the NASS/CDS sampling process specifically focuses on passenger car crashes, so the cases extracted only correspond to crashes in which a passenger vehicle was towed, and a motorcycle was somehow involved. Thus, a by-hand in-depth review of about 200 cases allowed retrieving 106 relevant crashes for this study, tending to represent the severe passenger vehicle(s) versus motorcycle(s) crashes on US roads. The findings lead to the conclusion that these crashes mostly result from the low conspicuity of the motorcycle, and from the inability of the car drivers to fully appreciate and anticipate the behavior of a motorcycle. Indeed, it has been shown that, first, the car drivers involved in these cases did not attempt any avoidance maneuver, second, they were largely of ages under 25, and finally, the majority of the crashes were in an intersection scenario. In addition, the two major scenarios unveiled were the car attempting a left turn from the opposite direction and the car attempting a left turn from the right. The paper mentions several solutions to enhance the motorcycle- conspicuity and to allow the car drivers to better anticipate its behavior, which seem to be key factors in the intersection-related crashes (and more generally in the passenger vehicle(s) versus motorcycle(s) crashes).
Bone fracture patterns could be crucial in reconstructing the nature of loading, especially in the lower limb and upper limb kinematics in vehicle-pedestrian crashes. In addition, use of FE bone models can be a handy tool to predict vehicle impact velocity and the impact direction. The point of fracture initiation in bone loading has been predicted quite accurately earlier. A methodology that predicts bone crack initiation and its propagation pattern for the six known loading directions using a single material and failure model is presented.
Pedestrian and cyclist are the most vulnerable road users in traffic crashes. One important aspect of this study was the comparable analysis of the exact impact configuration and the resulting injury patterns of pedestrians and cyclists in view of epidemiology. The secondary aim was assessment of head injury risks and kinematics of adult pedestrian and cyclists in primary and secondary impacts and to correlate the injuries related to physical parameters like HIC value, 3ms linear acceleration, and discuss the technical parameter with injuries observed in real-world accidents based documented real accidents of GIDAS and explains the head injuries by simulated load and impact conditions based on PC-Crash and MADYMO. A subsample of n=402 pedestrians and n=940 bicyclists from GIDAS database, Germany was used for preselection, from which 22 pedestrian and 18 cyclist accidents were selected for reconstruction by initially using PC-Crash to calculate impact conditions, such as vehicle impact velocity, vehicle kinematic sequence and throw out distance. The impact conditions then were employed to identify the initial conditions in simulation of MADYMO reconstruction. The results show that cyclists always suffer lower injury outcomes for the same accident severity. Differences in HIC, head relative impact velocity, 3ms linear contiguous acceleration, maximum angular velocity and acceleration, contact force, throwing distance and head contact timing are shown. The differences of landing conditions in secondary impacts of pedestrians and cyclists are also identified. Injury risk curves were generated by logistic regression model for each predicting physical parameters.
The accident research of Hanover and (from 1999 on) Dresden registered 736 leg injuries (AIS ≥ 2) from 1983 to March 2007. 174 of these injuries (23.6 %) were fractures or dislocations of foot and ankle. 149 feet of 141 front seat car occupants in 140 cars were affected. Of these 117 were drivers, 24 were front seat passengers. The mean age of occupants was 38.5 -± 16.8 years. Ankle fractures were the most frequent injury (n = 82; 80 malleolar fractures, 2 pilon fractures). 34 fractures and dislocations affected the hindfoot (5 talus and 26 calcaneal fractures, 2 subtalar dislocations and 1 subtotal amputation) , 16 to midfoot (4 navicular fractures, 5 cuboid fractures, 3 fractures of cuneiformia, 2 dislocations of chopart joint, 1 subtotal amputation, and one severe decollement) and 39 the forefoot (metatarsal fractures). Open fractures were seldom seen (2 malleolar fractures, 1 metatarsal fracture). Both feet were injured in 10 cases. 33 occupants (23.4 %) were polytaumatic had a polytrauma, 17 of them died. 81 percent of the occupants were belted. The cars were divided in pre EuroNCAP (year of manufacture 1997 and older) and post EuroNCAP cars (year of manufacture 1998 and newer). Most of the foot injuries were seen in pre EuroNCAP cars. Most of the occupants sat in compact cars (40 drivers and 9 front seat passengers) and large family cars (27 drivers and 7 co-drivers). 49 of 140 accidents occurred on country roads, 26 on main roads and 13 on motorways. The crash direction was mostly frontal. Generally were found no differences of delta v- and EES-level between the injured foot regions, but divided into pre- and post-EuroNCAP cars there was a tendency to higher delta v- and EES-levels in newer cars. The frequency of foot injuries increased linearly with increasing delta v-level; but above delta v-level of 55 km/h the linear increase only was seen in pre-EuroNCAP cars, post-EuroNCAP cars showed no further increase of injuries. The footwell intrusion showed no difference between the injured foot regions but pre-EuroNCAP cars had a tendency to higher footwell intrusion. There were no differences in footwell intrusion between the car types. Only 29 of 174 fractures or dislocations of foot were seen in post-EuroNCAP cars, the predominate number of these injuries (n = 145) were noticed in pre-EuroNCAP cars. A lower probability of long-term impairment was found in post-EuroNCAP cars for equal delta v levels, using the AIS2008 associated Functional Capacity Index (FCI) for the foot region.