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1

Evaluation of brain injury criteria based on reliability analysis

Hazay Máté, Bojtar Impre

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 1

173--185

EN

Purpose: Among the proposed brain injury metrics, Brain Injury Criteria (BrIC) is a promising tool for performing safety assessment of vehicles in the future. In this paper, the available risk curves of BrIC were re-evaluated with the use of reliability analysis and new risk curves were constructed for different injury types based on literature data of tissue-level tolerances. Moreover, the comparison of different injury metrics and their corresponding risk curves were performed. Methods: Tissue-level uncertainties of the effect and resistance were considered by random variables. The variability of the tissue-level predictors was quantified by the finite element reconstruction of 100 frontal crash tests which were performed in Simulated Injury Monitor environment. The applied tests were scaled to given BrIC magnitudes and the injury probabilities were calculated by Monte Carlo simulations. New risk curves were fitted to the observed results using Weibull and Lognormal distribution functions. Results: The available risk curves of diffuse axonal injury (DAI) could be slightly improved, and combined AIS 4+ risk curves were obtained by considering subdural hematoma and contusion as well. The performance of several injury metrics and their risk curves were evaluated based on the observed correlations with the tissue-level predictors. Conclusions: The cumulative strain damage measure and the BrIC provide the highest correlation (R2 = 0.61) and the most reliable risk curve for the evaluation of DAI. Although the observed correlation is smaller for other injury types, the BrIC and the associated reliability analysis-based risk curves seem to provide the best available method for estimating the brain injury risk for frontal crash tests.

2

The probability of traumatic brain injuries based on tissue-level reliability analysis

Hazay Máté, Bojtár Imre

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 1

141--152

EN

Motor vehicle crashes are one of the leading causes of traumatic brain injuries. Restraint systems of cars are evaluated by crash tests based on human tolerance data, however, the reliability of data currently used has been questioned several times in the literature due to the neglect of certain types of effects, injury types and uncertainties. Our main goal was to re-evaluate the currently applied risk curve by taking the previously neglected effects into account. Methods: In this paper, the probability of traumatic brain injury was determined by reliability analysis where different types of uncertainties are taken into account. The tissue-level response of the human brain in the case of frontal crashes was calculated by finite element analyses and the injury probability is determined by Monte Carlo simulations. Sensitivity analysis was also performed to identify which effects have considerable contribution to the injury risk. Results: Our results indicate a significantly larger injury risk than it is predicted by current safety standards. Accordingly, a new risk curve was constructed which follows a lognormal distribution with the following parameters: μLN = 6.5445 and LN = 1.1993. Sensitivity analysis confirmed that this difference primarily can be attributed to the rotational effects and tissue-level uncertainties. Conclusions: Results of the tissue-level reliability analysis enhance the belief that rotational effects are the primary cause of brain injuries. Accordingly, the use of a solely translational acceleration based injury metric contains several uncertainties which can lead to relatively high injury probabilities even if relatively small translational effects occur.

3

Szacowanie bezpieczeństwa transportu mieszaniny propan-butan metodami drzewa zdarzeń i niezdatności oraz metodą probabilistyczną

Michalski J.

Autobusy : technika, eksploatacja, systemy transportowe

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2018

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R. 19, nr 6

170--175, CD

PL

Oszacowano zagrożenie osób w wyniku pożaru pojazdu dostawczego z butlami 11 kg oraz 33 kg zawierającymi propan-butan techniczny, spowodowanego ich nieszczelnością. Wyznaczono prawdopodobieństwo rozszczelnienia butli z gazem skroplonym LPG, w ciągu roku podczas czynności załadunku, wyładunku i transportu w firmie handlu oboźnego. Oszacowano cząstkowe i całkowite ryzyka wystąpienia ciężkiego obrażenia ciała kierowcy oraz ryzyko jego śmierci w przypadku zdarzenia pożaru na skrzyni ładunkowej oraz zdarzenia wystrzału opony. W ocenie ryzyka zastosowano metody drzewa zdarzeń/niezawodności i drzewa niezdatności/błędu oraz metodę probabilistyczną.

EN

The threat of people as a result of delivery vehicle fire handling 11 kg and 33 kg bottles with propane-butane, due to leakage of these bottles was estimated. The probability of unsealing LPG bottles with gas during the year at loading, unloading and transport operations in carrier trade company was determined. Partial and total risk of serious driver injuries and the risk of death in the event of a fire in open load-carrying body of the car and tire damage was estimated. The risk assessment uses the methods of the event and fault tree as well as the probabilistic method.

4

Analysis of the influence of the car impact velocity on the loads of the dummies in the front and rear seats

Żuchowski A.

Archiwum Motoryzacji

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2018

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Vol. 81, nr 3

141--158

PL

It was considered an influence of the velocity, at which the passenger car hits into the obstacle on the dynamic loads of the dummies in the front and back seats. For this purpose, the results of 28 crash tests published on the Internet by the National Highway Traffic Safety Administration (U.S.A.) were used. The crash tests of 14 models of the cars were conducted at two values of the impact velocity, at which the cars hits into a barrier (40 and 56 km/h, as well as 48 and 56 km/h). It was shown an influence of the impact velocity on the car deceleration and their deformation specification. It was paid attention to the loads of a driver and a passenger in the front seats (dummies representing a 5-centile men and 5-centile woman) and the passengers in the back seats (dummies representing a 5-centile woman and a 6-year-old child). During an evaluation of the dummy loads were employed the indicators of biomechanical impedance of the human body in respect of the effects of the impact loads related to the head, neck and chest. It was determined that an increase of the velocity at the moment of hitting into an obstacle from 40 km/h up to 56 km/h results in the increase in the risk of serious injury (AIS3+) of the 5-centile woman from 30÷60% to 35÷90%. Increasing the velocity at which a car hits an obstacle from 48 km/h up to 56 km/h results in the increase in the risk of severe injury of the 50-centile woman from 25÷40% to 30÷55%. It was emphasised that the effectiveness of the airbag may depend on the impact velocity, at which car hits the obstacle.

5

Analysis of the influence of the impact speed on the risk of injury of the driver and front passenger of a passenger car

Żuchowski A

Eksploatacja i Niezawodność

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2016

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Vol. 18, no. 3

436--444

EN

The subject of the analysis was the influence of the speed, at which a personal car hit an obstacle, on the risk of injury of the driver and the passenger sitting in the front seat. With this goal in mind, several hundred of crash tests were analysed, published on the Internet by National Highway Traffic Safety Administration (USA). The analysis focuses on the cases involving a frontal impact of the car on a rigid barrier. For the purpose of assessing the forces acting on a dummy, Head Injury Criterion (HIC36) and Chest Acceleration (CAcc), were applied, calculated on the basis of the resulting acceleration of head and chest of the dummy. Separate analyses were performed for the forces acting on the dummy representing 50-centile man (M50) and 5-centile woman (F5). A statistical analysis of the results of the crash tests was performed in order to determine the typical values of HIC36 and CAcc factors, as well as the risk of severe injury of the driver and the passenger at a given collision speed. The risk of injury was calculated on the basis of provided in the research literature so-called injury risk curves. It was determined that increasing the speed at which a car hits an obstacle from 25 km/h up to 56 km/h results in the increase in the risk of severe injury (AIS4) of the driver and the passenger from 2 to 10%. Some functions were proposed, describing the relation between the risk of injury and the velocity of collision.

PL

Rozważono wpływ prędkości uderzenia samochodu osobowego w przeszkodę na ryzyko obrażeń kierowcy oraz pasażera na przednim fotelu. W tym celu wykorzystano wyniki kilkuset testów zderzeniowych, udostępnionych w Internecie przez National Highway Traffic Safety Administration (USA). Uwagę skupiono na czołowe uderzenie samochodu w sztywną barierę. Podczas oceny obciążeń manekinów wykorzystano wskaźniki obrażeń głowy HIC36 oraz torsu CAcc, które oblicza się na podstawie wypadkowego przyspieszenia działającego na głowę i tors manekina. Oddzielnie rozważono obciążenia manekina reprezentującego 50-centylowego mężczyznę (M50) oraz 5-centylową kobietę (F5). Przeprowadzono statystyczną ocenę wyników testów zderzeniowych, której celem było określenie dominujących wartości wskaźników HIC36 i CAcc oraz ryzyka ciężkich obrażeń kierowcy i pasażera przy danej prędkości zderzenia. Ryzyko obrażeń obliczono na podstawie dostępnych w literaturze tzw. funkcji ryzyka obrażeń. Ustalono, że zwiększenie prędkości uderzenia samochodu w przeszkodę z 25 km/h do 56 km/h zwiększa ryzyko ciężkich obrażeń (AIS4) kierowcy i pasażera z 2 do 10%. Zaproponowano funkcje wiążące ryzyko obrażeń i prędkość zderzenia.

6

Ocena ryzyka obrażeń pasażerów podczas wypadku drogowego mikrobusu, jako kryterium doskonalenia konstrukcji foteli i ich rozmieszczenia

Żuchowski A., Prochowski L., Zielonka K.

Logistyka

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2014

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nr 3

7166--7174

PL

Bezpieczeństwo przewozu osób mikrobusami to rozległe zagadnienie, które wymaga wielu badań i analiz. Konieczne jest poszukiwanie rozwiązań kompromisowych pomiędzy funkcją foteli w zakresie poprawy komfortu jazdy, dążeniem do minimalizacji ryzyka obrażeń w czasie wypadku drogowego, a koniecznością transportu możliwie dużej liczby pasażerów. Celem prowadzonych rozważań jest opracowanie metody obliczeniowej, w której obecnie rozpoznawane relacje pomiędzy cechami konstrukcyjnymi foteli, ich rozmieszczeniem w mikrobusie oraz działaniem środków ochrony indywidualnej na osoby o różnych cechach antropometrycznych zostaną wykorzystane do liczbowej oceny ryzyka obrażeń pasażerów podczas wypadku drogowego. Opisywane relacje są analizowane na podstawie wyników coraz szerzej prowadzonych badań eksperymentalnych i symulacji komputerowej w tym zakresie.

EN

The safety of passenger transportation by minibuses is a complex issue, which requires extensive research and analyses. Solutions must be sought that would be a compromise between the seat functions aimed at achieving the best possible ride comfort, the striving to minimize the risk of injury in case of a road accident, and the necessity to transport as many passengers as possible. Deliberations have been presented that would lead to developing a calculation method, where the relations recognized at present between constructional features of seats, deployment of seats in a minibus, and action of individual protection means on people with different anthropometric features would be used for numerical evaluation of the risk of injuries to vehicle passengers during a road accident. The relations under consideration are analysed on the grounds of results of experimental research and computer simulations, which are more and more widely carried out on these issues.

7

Results of preliminary experimental research and computer simulation concerning assessment of injury risk of occupants of military off-road vehicle impacting an obstacle

Orłowski L.

Journal of KONES

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2007

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Vol. 14, No. 3

485-494

EN

A survey was made on the available designs of guard rails, gates and other structures of the type, the "Dzik"-type vehicle might have to ram into during some operations. Basing on the conducted analyses, two typical models of those barriers were constructed. The first, rigid barrier had a form of concrete block of 6000 kg, while the flexible one was made of steel sections. Since no "Dzik" vehicle was available, a series of preliminary experiments were made on a "STAR" truck which had a similar frame and a bumper located at the same level. The vehicle was subjected to a proper load and during the experiment it impacted the constructed barriers. In the course of crash the values of most important parameters (forces, accelerations) were registered. The results obtained allowed for parametrical identification of a numerical model developed using the MADYMO software. Numerical simulations were performed for different crash speed with the numerical models of human and dummies adapted accordingly to take into consideration that the crew is supplied with bullet-proof jackets and helmets. Both the "sled-test" type numerical simulations, in which the accelerations measured in experiment were employed (after proper adjustment, for higher velocities), and simulations of the complete barrier-vehicle-occupant system were performed. Basing on the numerical simulation results the level of risk the crew is exposed to have been estimated, proving the necessity for developing a proper crew protection system. The scope of further experimental and numerical investigations, to achieve the goal, has been determined.

PL

Przeprowadzono przegląd stosowanych rozwiązań w zakresie budowy ogrodzeń, bram i podobnych konstrukcji, dla których może pojawić się konieczność taranowania w trakcie akcji z wykorzystaniem pojazdu typu „Dzik". Na podstawie przeprowadzonych analiz opracowano dwie typowe przeszkody modelowe. Przeszkodę sztywną zrealizowaną w postaci betonowego bloku o masie 6000 kg na betonowym podłożu i przeszkodę podatną w postaci Stalowych kształtowników. Dla tak zbudowanych modeli przeszkód przeprowadzono serie badań doświadczalnych (dla bezpiecznych zakresów prędkości zderzenia) wykorzystując, wobec okresowego braku możliwości użycia pojazdu „Dzik", odpowiednio obciążony samochód STAR o zbliżonej konstrukcji ramy i takim samym poziomie zderzaka. Przeprowadzone badania eksperymentalne, w których rejestrowano przebiegi istotnych wielkości (sił, przyspieszeń) w trakcie zderzeń, pozwoliły na identyfikację parametrów modelu symulacyjnego opracowanego w środowisku systemu MADYMO. Przeprowadzono szereg symulacji komputerowych (dla różnych prędkości zderzenia) z wykorzystaniem komputerowych modeli człowieka i manekinów z bazy MADYMO. Oryginalne modele, opracowane dla zastosowań „cywilnych", zostały odpowiednio zmodyfikowane — uwzględniono fakt wyposażenia załogi pojazdu w czasie interwencji w kamizelki kuloodporne i hełmy. Przeprowadzono zarówno badania typu „sled-test", w których jako wymuszenie wykorzystano bezpośrednio przyspieszenia rejestrowane w czasie badań eksperymentalnych (odpowiednio przeskalowane dla większych prędkości), jak też badania pełnego modelu przeszkoda-pojazd-załoga. Wykorzystując wyniki symulacji komputerowych określono poziom zagrożeń dla załogi pojazdu uzasadniający potrzebę opracowania odpowiedniego systemu zabezpieczenia załogi. Określono również kierunki oraz zakres niezbędnych dalszych prac eksperymentalnych i symulacyjnych.