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1

Pedestrian dynamic response and injury risk in high speed vehicle crashes

Nie Jin, Lv Xiaojiang, Li Kui, Li Guibing, Huang Xing

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 3

57--67

EN

The purpose of the current study is to understand pedestrian kinematics, biomechanical response and injury risk in high speed vehicle crashes. Methods: Vehicle-to-pedestrian crashes at the impact speeds of 40 km/h (reference set) and 70 km/h (analysis set) were simulated employing FE models of a sedan front and an SUV front together with a pedestrian FE model developed using hollow structures. The predictions from crash simulations of different vehicle types and impact speeds were compared and analyzed. Results: In crashes at 70 km/h, pedestrian head-vehicle contact velocity is by about 20–30% higher than the vehicle impact speed, the peak head angular velocity exceeds 100 rad/s and is close to the instant of head-vehicle contact, brain strain appears two peaks and the second peak (after head contact) is obviously higher than the first (before head contact), and AIS4+ head injury risk is above 50%, excessive thorax compression induces rib fractures and lung compression, both sedan and SUV cases show a high risk (>70%) of AIS3 + thorax injury, and the risk of AIS4 + thorax injury is lower than 40% in the sedan case and higher than 50% for the SUV case. Conclusions: Pedestrians in vehicle crashes at 70 km/h have a higher AIS3 + /AIS4 + head and thorax injury risk, high vehicle impact speed is more easily to induce a high head angular velocity at the instant of head-vehicle contact, brain strain is strongly associated with the combined effect of head rotational velocity and acceleration, and pedestrian thorax injury risk is more sensitive to vehicle impact speed than the head.

2

Biomechanical analysis of thorax-abdomen response of vehicle occupant under seat belt load considering different frontal crash pulses

Qiu Jinlong, Li Kui, Xiang Hongyi, Xie Jingru, Fan Zhuangqin, Qin Mingxin

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 4

31--38

EN

The purpose of this work was to understand the biomechanical response and injury risk of thorax and abdomen of vehicle front seat occupants caused by seat belt load under different frontal crash pulses. Methods: A vehicle-seat-occupant subsystem finite element (FE) model was developed using the a assembly of vehicle front seat and seat belt together with the THUMS (Total Human body Model for Safety) AM50 (50th% Adult Male) occupant model. Then the typical vehicle frontal crash pulses from different impact scenarios were applied to the vehicle-seat-occupant subsystem FE model, and the predictions from the occupant model were analyzed. Results: The modeling results indicate that the maximum sternal compression of the occupant caused by seat belt load is not sensitive to the peek of the crash pulse but sensitive to the energy contained by the crash pulse in the phrase before seat belt load reaching its limit. Injury risk analysis implies that seat belt load of the four crash scenarios considered in the current work could induce a high thorax AIS2+ injury risk (>80%) to the occupants older than 70 years, and a potential injury risk to the spleen. Conclusions: The findings suggest that control of the energy in the first 75 ms of the crash pulse is crucial for vehicle safety design, and thorax tolerance of the older population and spleen injury prevention are the key considerations in developing of seat belt system.

3

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.

4

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.

5

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.

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A Methodology for Assessing Blast Protection in Explosive Ordnance Disposal Bomb Suits

Bass C., Davis M., Rafaels K., Rountree M., Harris R. M., Sanderson E., Andrefsky W., DiMarco G., Zielinski M.

International Journal of Occupational Safety and Ergonomics

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2005

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Vol. 11, No. 4

347--361

EN

To reduce human casualties associated with explosive ordnance disposal, a wide range of protective wear has been designed to shield against the blast effects of improvised explosive devices and munitions. In this study, 4 commercially available bomb suits, representing a range of materials and armor masses, were evaluated against 0.227 and 0.567 kg of spherical C-4 explosives to determine the level of protection offered to the head, neck, and thorax. A Hybrid III dummy, an instrumented human surrogate [1], was tested with and without protection from the 4 commercially available bomb suits. 20 tests with the dummy torso mounted to simulate a kneeling position were performed to confirm repeatability and robustness of the dummies, as well as to evaluate the 4 suits. Correlations between injury risk assessments based on past human or animal injury model data and various parameters such as bomb suit mass, projected area, and dummy coverage area were drawn.