crespo, S.; perez rapela, D.; roman-marin, J.; Martin-Vázquez, .; Luzon, B.; Arregui-Dalmases, C. International Research Council on the Biomechanics of Injury Conference p. 1-14 Data de presentació: 2016-09-15 Presentació treball a congrés
Euro NCAP continually examines and modifies its protocols to encourage the automotive industry to improve vehicles and the safety of occupants. The aim of this study is to identify the key differences between the past and current Euro NCAP protocols regarding side impact, in order to apply optimized countermeasures for fulfilling the new requirements in a previously designed vehicle. Outcomes from a possible Euro NCAP increase in crash speed from 50 km/h to 60 km/h were evaluated.
The current protocol introduces the dummy WorldSID 50th percentile and changes in the barrier. The changes in the dummy lead to a reduction in the distance between the occupant and the door panel, and the current geometry of the barrier causes the car’s structure, in particular the sill, to be additionally loaded. An increase in mass of the current barrier causes an increase in energy absorption, thus presenting different deformation patterns. With the updated protocol, the most critical anatomical areas observed in this research were the pelvis and the shoulder. Countermeasures in this study were especially focused on decreasing the load on these anatomical structures. The evaluated countermeasures were:
- Sill and B-pillar geometric adaptation to better perform against the AE-MDB
- Reduced stiffness of the door panel at the occupant impact location
- Optimized door beam
Finite Element Method (FEM) tools were used as the basis of this research, including validated and correlated models with experimental full car tests. Initially, the research started with FEM testing of the current vehicle according to both past and current Euro NCAP protocols.
Pelvic biomechanical values reached the lower performance limits when testing the AE-MDB barrier at 50 km/h. This new test has an especial impact in midsized cars in terms of pelvis loading, leading the pubic and sacroiliac forces to increase in 38.6% and 25.8% respectively, in the vehicle studied. After the application of the structural countermeasures, the sacroiliac force decreased by 24.9% and the pubic force decreased by 32.5%.
Changes in the Euro NCAP protocol and regulations are always a challenge for design departments. In this research the differences between Euro NCAP side protocols were analyzed and some potential countermeasures were highlighted.
Many factors should be considered in order to understand properly how a mechanical input to the head can result in a determined type of head injury: the severity, the nature of the mechanical input, the impact location, the direction of this input, the age of the patient, his gender, anthropometrics and previous state, and also the treatment and recovery of the patient.
Head injuries are either the most or second most commonly reported injuries to pedestrians struck by vehicles. Furthermore, among serious or life-threatening head and brain injuries far outnumber injuries to all other body regions. Around 40% of the adult head injuries are due to windshield impact.
Windshield modeling is currently a challenge in head pedestrian protection, the way the windshield breaks introduces a significant change in the Head Injury Criteria, and this is due to the non-lineal fracture that the glass is presenting during the headform collision. In this paper a new model for windshield pedestrian impact is presented for optimizing experimental-simulation correlation.
In this research a total of 90 experimental windshield test were performed, the head impacts were simulated using the software ANSA+PAMCRASH+META. The model was optimized through parametric adjustment methods.
With this present model the average HIC deviation between testing and simulation has been reduced in average below 10%
Hurtado , M.; Luzon, B.; Rodriguez-Perdices, J.; Trullols, R.; Puttenstein, H.; Arregui-Dalmases, C. Congreso Ibero-Americano de Seguridad Vial p. 1-20 Data de presentació: 2014-09-30 Presentació treball a congrés
El diseño de un vehículo requiere múltiples fases de experimentación con vehículos físicos completos, esta experimentación se torna compleja en las fases iniciales, dada la carencia de piezas físicas y carrocerías completas. Esta investigación persigue predecir en una fase inicial de desarrollo el comportamiento que presentará el vehículo completo en cuanto a la protección del peatón.
Con este objetivo se establecen los requisitos para el diseño de un muleto para protección de peatones, este estudio ha llevado a cabo pruebas de impacto de cabeza de adulto para investigar las características de rigidez del vehículo en la zona de contacto entre la cabeza del peatón adulto y el parabrisas en su unión con el tablero, zonas de muy difícil simulación y de gran importancia para la protección del peatón.
El estudio se realizó con un muleto construido a medida en que se agregan y se sustraen elementos del vehículo completo, posteriormente se realizan impactos de cabeza de peatón y se mide el HIC (Criterio biomecánico de impacto de cabeza), siguiendo el protocolo de prueba de peatones EuroNCAP. Los impactos en el muleto se compararon con impactos idénticos en un vehículo completo usado como referencia experimental.
El estudio determinó que la reproducción correcta de las uniones laterales entre el tablero y la estructura de la carrocería juega un papel esencial en el comportamiento de impacto global, el efecto del parabrisas fue más enmascarador de lo esperado. Este trabajo presenta a la comunidad científica una herramienta útil para el diseño del tablero y sus fijaciones asociados a la protección de peatones en las fases tempranas del desarrollo.
Objective: The objective of this study is to assess the response of postmortem human subjects (PMHS) to a large-volume side air bag in a fully instrumented and well-controlled side impact test condition.
Methods: Three adult male PMHS were subjected to right-side pure lateral impacts. Each stationary seated subject was struck at 4.3 0.1m/s by a rigid wall installed on a 1700-kg rail-mounted sled. Each subject was held stationary by a system of tethers until immediately prior to being impacted by the moving wall. A large side air bag was mounted to the wall and deployed so that it was fully inflated at the time it contacted the subject's right side. The load wall consisted of an adjustable matrix of 15 individual plates, each supported by a 5-axis load cell that recorded the interaction between the subject and impacting wall. Two-dimensional (external) torso deformation was provided by a chest band that encircled the torso at the level of the sixth rib laterally. Triaxial acceleration was measured at the head, spine, and sacrum via 3 orthogonal accelerometers mounted to the same bone-mounted hardware that held the marker clusters used for kinematic analysis.
Results: Peak pelvic load normal to the wall averaged 6.8 kN, which was over 5times that recorded for the shoulder (1.3 kN) and the thorax (1.2 kN). Lateral chest deflection ranged from 9 to 21mm. Two of the 3 subjects sustained 2 and 9 fractures, respectively.
Conclusions: Two of the 3 PMHS sustained rib fractures despite low levels of thorax deflection. We attribute this finding to individual variability in subject injury tolerance. Other response parameters exhibited lower levels of variability and characterize PMHS response to a potentially beneficial side impact countermeasure. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.
Park, G.; Kim, T.; Crandall, J.R.; Arregui-Dalmases, C.; Luzon, B. International Research Council on the Biomechanics of Injury Conference p. 368-379 Data de presentació: 2013-09-11 Presentació treball a congrés
The goal of this study was to evaluate the biofidelity of the Global Human Body Models Consortium (GHBMC) human body model under a side impact loading condition with an airbag, and analyze the effect of initial position of the model on the response. Shaw et al. conducted side impact sled tests using three Post mortem human surrogates (PMHS) with impact speeds of 4.3 ± 0.1 m/s, and used a rigid wall boundary condition with an airbag mounted to the sled. The correlation between the PMHS and the GHBMC was evaluated using the CORA rating method. The rating ranged from 0.27 to 0.69 along the body regions on a scale in which a rating of 1.0 indicated a perfect correlation between the PMHS and the GHBMC. The pelvis and thorax region showed good correlation with those of the PMHS while the spinal regions did not. In addition, the roll and yaw angle of the initial position of the PMHS had an effect on the response of subjects. The result of this research indicated two points, that the GHBMC model should be validated focusing on the internal biofidelity of the model, and that the yaw and roll angle should be carefully controlled during a side impact test.
Luzon, B.; Arregui-Dalmases, C.; Hernando, L.; Core, E.; Narbona, A.; Selgas, C. International journal of crashworthiness Vol. 19, num. 3, p. 209-221 DOI: 10.1080/13588265.2013.802938 Data de publicació: 2013-06-06 Article en revista
This research presents six simultaneous innovative occupant near side lateral impact protection concepts, including a dynamic door, a high-volume side airbag, a large external airbag that covers doors, sill and B-pillar of the struck vehicle and other concepts for increasing the distance between the occupant and the door panel (active armrest, inflatable door beam and moving seat). All systems are based on pre-crash detection of the impact and are activated as soon as 80 ms before the impact. This paper details the task of integrating these systems into a vehicle using finite element models, sled tests and full scale crash tests.
This research presents six simultaneous innovative occupant near side lateral impact protection concepts including a dynamic door, high-volume side airbag, a large external airbag that covers doors, sill and B-pillar of the struck vehicle and other concepts for increasing the distance between the occupant and the door panel (active armrest, inflatable door beam and moving seat). All systems are based on pre crash detection of the impact and are activated as soon as 80ms before the impact.
This paper details the task of integrating these systems into a vehicle using FE models, sled tests, and full scale crash tests. Sled test dummy responses were compared with and without the countermeasures.
Velazquez-Ameijide, J.; Sanchez, D.; Martinez-Gonzalez, E.; Luzon, B.; Arregui-Dalmases, C. Congreso Universitario de Innovación Educativa en las Enseñanzas Técnicas p. 26-27 Data de presentació: 2011-07-07 Presentació treball a congrés
[...]En el presente artículo se resumen algunos de los aspectos y se comenta acerca de la reciente creación en todo el mundo de equipos multidisciplinares que realizan de manera sistemática investigaciones “en profundidad” (“in-depth”) de los accidentes de tráfico.
Arregui-Dalmases, C.; Luzon, B.; Camps, G.; Lluma, J.; Ruiz, C. Congreso Universitario de Innovación Educativa en las Enseñanzas Técnicas p. 1-7 Data de presentació: 2004-07-26 Presentació treball a congrés