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Rider Stature Influence to Injury Risk in Motorcycle Rear Impact to Car

University of West Bohemia-Ludek Hyncik, Tomasz Bonkowski
Tianjin University of Science and Technology-Wenle Lv
Published 2019-03-25 by SAE International in United States
Road traffic accidents cause one of the highest numbers of severe injuries. Approximately 1.25 million people die each year as a result of road traffic crashes and between 20 and 50 million more people suffer non-fatal injuries, with many incurring a disability. Nearly half of those dying on the roads are so-called vulnerable road users, namely pedestrians, cyclists and two-wheeler riders including motorcyclists. Those vulnerable road users usually undergo complex kinematics and complex loading caused by the other vehicle impact.Virtual human body biomechanical models play an important role to assess the injuries during the impact loading especially for scenarios, where complex dynamical loading is taken into account. An additional benefit of some virtual human models is their scalability, so that they can assess the injury risk for the particular subject taking into account a wide spectrum of the whole population.The presented work shows the motorcycle rider injury risk analysis during the rear motorcycle accident to the car using the virtual approach by the numerical simulation taking into account the variability of the human body. The…
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Novel Approach in Vehicle Front-End Modeling for Numerical Analyses of Pedestrian Impact Scenarios

University of West Bohemia-Jan Vychytil, Jan Spicka, Ludek Hyncik
Brano a.s.-Radek Valasek
Published 2017-03-28 by SAE International in United States
In this paper a novel approach in developing a simplified model of a vehicle front-end is presented. Its surface is segmented to form an MBS model with hundreds of rigid bodies connected via translational joints to a base body. Local stiffness of each joint is calibrated using a headform or a legform impactor corresponding to the EuroNCAP mapping. Hence, the distribution of stiffness of the front-end is taken into account. The model of the front-end is embedded in a whole model of a small car in a simulation of a real accident. The VIRTHUMAN model is scaled in height, weight and age to represent precisely the pedestrian involved. Injury risk predicted by simulation is in correlation with data from real accident. Namely, injuries of head, chest and lower extremities are confirmed. Finally, mechanical response of developed vehicle model is compared to an FE model of the same vehicle in a pedestrian impact scenario. VIRTHUMAN model of a 13-year-old boy (150 cm, 40 kg) is chosen to represent the pedestrian and the lateral impact at 45…
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Prediction of Injury Risk in Pedestrian Accidents Using Virtual Human Model VIRTHUMAN: Real Case and Parametric Study

University of West Bohemia-Jan Vychytil, Ludek Hyncik
BRANO a.s.-Radek Valasek
Published 2016-04-05 by SAE International in United States
In this work we present the VIRTHUMAN model as a tool for injury risk assessment in pedestrian crash scenarios. It is a virtual human body model formed of a multibody structure and deformable segments to account for the mechanical response of soft tissues. Extensive validation has been performed to ensure its biofidelity. Due to the scaling algorithm implemented, variations in the human population in terms of height, weight, gender and age can be considered. Assessment of the injury risk is done via automatic evaluation software developed. Injury criteria for individual body parts are evaluated using accelerations, forces and displacements of certain points. Injury risk is indicated by the colour of particular body parts in accordance with NCAP rating. A real accident is investigated in this work. A 60-year-old female was hit laterally by a passenger vehicle with the impact velocity of 40 km/h. The accident is reconstructed using VIRTHUMAN as pedestrian representative. Good agreement of the simulation and real data in terms of falling distance and injury sustained by pedestrian is obtained. Finally, a parametric…
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Scalable Multi-Purpose Virtual Human Model for Future Safety Assessment

University of West Bohemia-Jan Vychytil, Hana Cechova, Stanislav Spirk, Ludek Hyncik
MECAS ESI s.r.o.-Jaroslav Manas, Ludek Kovar
Published 2014-04-01 by SAE International in United States
The paper concerns the development of a new scalable virtual human body model. The model has been developed to assess safety risk during various complex crash scenarios including impacts from different directions. The novel approach described couples the basic multi-body structure with deformable segments, resulting in short calculation time. Each multi-body structure segment carries the particular surface parts that are linked to the segment with non-linear springs representing the behavior of related soft tissues.The response of particular body segments (head, thorax, pelvis, lower extremities) is validated in known impact scenarios and the response of the model is tuned to the experimental corridors obtained from literature. The tuning process involved the adjustment of both model material and numerical parameters in order to get the correct response for all the tests. Several energy level impacts from different directions are usually considered in order to generalize the model; to test its robustness and correct biofidelic performance.The model is designed modularly to be simply adopted towards the pre-defined height, age and mass. The developed model is useful for the…
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Development of 6 Years Old Child Virtual Model by Automatic Scaling

University of West Bohemia-Ludek Hyncik, Jan Spicka, Stanislav Spirk
MECAS ESI s.r.o.-Jaroslav Manas, Ludek Kovar
Published 2014-03-24 by SAE International in United States
Traffic accidents cause one of the highest numbers of severe injuries in the whole population. The numbers of deaths or seriously injured citizens prove that traffic accidents and their consequences are still a serious problem to be solved.A lot of effort is devoted to both passive and active safety systems development. The transportation standards usually define safety requirements by regulations (e.g. ECE-R94, 96/79/EC and ECE-R95, 96/27/EC in Europe) with specific dummies for children to be used. The dummies include hardware sensors for monitoring accelerations, loads and other signals and each dummy is developed for a specific scenario, but there are limitations of these dummies, such as only a specific age or calibration just for a specific test. Taking into account that the consequence of a traffic accident is highly influenced by the stature of the body, virtual human body models, including those for children, start to play a significant role because they can be scaled or even personalized towards a particular population or even a particular person.The paper contributes to the field of vehicle safety…
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On Scaling Virtual Human Models

University of West Bohemia-Ludek Hyncik, Hana Cechova, Pavel Blaha
MECAS ESI s.r.o.-Ludek Kovar
Published 2013-03-25 by SAE International in United States
The paper contributes to the development of virtual biomechanical human models as a support for design and optimization of both passive and active safety systems used in various modes of transportation. The paper shows the scaling methodology as simply as possible to creating models based on a reference model regarding anthropology and flexibility.The paper describes the methodology for the scaling of hybrid human models based on a multi-body structure carrying deformable parts. The idea is to have a reference model and to create other models automatically based on the least possible number of parameters. The developed method takes into account the height, age, mass and flexibility of joints. The scaling process starts by scaling the reference model to the target height for given age (including correct height for each major segment of the human body) based on the available anthropometrical data. The scaling coefficient for each segment is also used to scale the segment mass. Secondly, the model mass is balanced to the target mass. Finally, the flexibility of all major joints is updated concerning…
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Virtual Car Crash Simulation

University of West Bohemia-Ludek Hyncik, Jaromir Svigler, Vit Novacek
Charles Univ.-Josef Stingl, Alena Doubkova
  • Technical Paper
  • 2004-05-0291
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
The growing intensity of automotive traffic is accompanied by fluent elevation of frequency of car crashes joined in many cases with serious injuries and/or deaths of occupants. These facts strongly influence the efforts of car designers to improve the passive safety parameters, e.g., the restrain systems of cars, protecting above all the head, neck and thorax. In this way the most serious consequences of accidents should be restricted and ensure the passengers to survive the crash. Till now, less attention was paid to the protection of abdominal organs, whose injuries during traffic accidents can have very serious consequences.The work shows the simulation of a real frontal-car-to-car crash with offset between a passenger car and a truck. The aim of the task is the simulation of the passenger car driver behavior during the first crucial milliseconds of the accident. Based on police data (photos, accident plans and speed recorder), the analysis of the accident is thoroughly done and the deceleration of the crashing car is derived. Basic passenger car interior geometry is obtained and reconstructed as…

New Sight on the Gap Between Stator and Tooth Surfaces of Screw Machines

University of West Bohemia-J. Švígler
  • Technical Paper
  • 2003-04-0115
Published 2003-09-07 by Institution of Mechanical Engineers in United Kingdom
The important part of the work space of the screw machines is its boundary surface, where the technically necessary and unadvisable gaps, which cause medium leakage and are the source of undesirable inner losses, take place. The gap between surfaces of rotors, rotating in the stationary space of the stator, is one of the most important gaps. The lose space caused by this gap is at present modeled as a 2D one. In the paper a new, spatial mathematical model of the mentioned gap is constituted. The spatial model shows that the leakage gap is significantly higher than that considered in computations till now.

Partial steam admission in an axial turbine stage

University of West Bohemia-J. Skopek, J. Vomela
SKODA ENERGO sro-L. Tajc, J. Polansky
  • Technical Paper
  • 1999-04-0109
Published 1999-03-02 by Institution of Mechanical Engineers in United Kingdom
Some results are presented here of an experimental research work on steam and air turbines, which was focused on the clarification of the processes developing in an impulse axial turbine stage with partial steam admission. The effects of axial distance, the velocities ratio, the Mach number, the admission rate and other parameters on the stage efficiency were investigated. Simulation of the steam flow through the stage was performed by computation. Computation enabled better understanding and clarification of those processes, which occur at the moment of the moving blades transition into the blocked part of the stage. Measurement on two experimental turbines enabled the comparison of the results in wide range of Mach numbers and axial distances. Analysis of the measured data was performed and the influence of ventilation losses was separated.