Wyniki wyszukiwania - BazTech

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Experimental research of energy absorbing structures within helmet samples made with the additive manufacturing method – preliminary study

Tobola Wojciech, Papis Mateusz, Jastrzębski Dominik, Perz Rafał

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 1

127--136

EN

This study aimed to develop an energy-absorbing structure for bicycle helmets to minimize head injuries caused by collisions. The research team explored three geometric structures produced through additive methods and compares their energy absorption properties with a standard bicycle helmet made of Expanded Polystyrene (EPS) foam. Methods: The study prepared samples of three geometric structures (a ball, a honeycomb and a conical shape) and a fragment of a bicycle helmet made of EPS foam with the same overall dimensions. Laboratory tests were conducted using a pneumatic hammer, piston compressor, anvil, triaxial accelerometer and data processing systems. Three crash tests were performed for each type of structure, and the anvil's maximum acceleration and stopping distance after the crash were analyzed. Results: The study found that the energy absorption properties of the Polylactic Acid (PLA) material printed with the incremental method were comparable or better than those of the EPS material used in helmets. The geometric structure of the energy-absorbing material played a crucial role in its effectiveness. The most promising results were obtained for the ball samples. Conclusions: The study concluded that further research on energy-absorbing structures made using the Fused Deposition Modeling (FDM) method could be useful in the production of bicycle helmets. The results show that the geometric structure of the energy-absorbing material is a crucial factor in its effectiveness. The findings suggest that the ballshaped structure made with PLA material printed using the incremental method could be a promising design for bicycle helmets to minimize head injuries caused by collisions.

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Rib kinematics analysis in oblique and lateral impact tests

Jastrzębski Dominik, Perz Rafał

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 1

135--141

EN

Understanding thorax kinematics and rib breaking mechanisms in conditions of oblique and lateral impact is crucial in safety systems development. To increase knowledge level on this subject, simulation and experimental tests are necessary. The purpose of this study was to obtain single rib kinematics in the case of oblique and lateral impact conditions using numerical simulation approach. Methods: Two impact tests using human body model of a 50th percentile man (THUMS v4.0.1 AM50) were performed in LS-Dyna R7.1.1. Impactor was a rigid cylinder with a diameter of 152 mm, and velocity equal to 6.7 m/s. Impact angle measured to sagittal plane was 30 and 90°, respectively in oblique and lateral impact case. Results: Kinematics of ribs from 3rd to 6th were analyzed. Results shown significant similarities between oblique impact and kinematics of ribs tested in frontal impact conditions in the literature, with maximal costochondral joint displacement relatively to costovertebral joint varying from 65.4 mm (3rd rib) to 82.0 mm (5th rib). Deformation of rib in lateral impact conditions was different than during oblique impact test, with distinctive “flattening” approximately in the middle of the rib. Maximal relative displacement varies from 16.4 mm (6th rib) to 26.6 mm (5th rib) and its location depends on the analyzed rib. Conclusions: Oblique impact scenario may be simulated for the single rib on an experimental way using set-up of the frontal impact. Experimental simulation of the lateral impact for the single rib should not use the same set-up, as the kinematics analysis showed significant differences between simulated cases.

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Driver reliability and behavior study based on a car simulator station tests in ACC system scenarios

Papis Mateusz, Jastrzębski Dominik, Kopyt Antoni, Matyjewski Marek, Mirosław Marcin

Eksploatacja i Niezawodność

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2019

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Vol. 21, no. 3

511--521

EN

Nowadays Advanced Driver Assistant Systems (ADAS) are becoming more popular in car equipment. During ADAS development process it is necessary to prepare numerical models and perform simulation tests, so the systems could be safely implemented. However, because these systems are directly connected to a human – machine interface, volunteer tests on a car simulator are conducted. They are indispensable for testing the correct operation of the system, but above all for showing differences in the operation of the system and a driver in terms of human reliability. Presented research shows results of simulator tests in two cases: extra - urban and mixed scenarios. The tests were classic, tracking tasks in which the driver was required to keep a safe, predefined distance from the leading car. Consequently, the results of experiments were compared to results of the reference car performance, i.e. the car equipped with Adaptative Cruise Control system. It made possible to assess the driver reliability. Moreover, questionnaire tests (NASA TLX) were also applied to assess subjects’ workload. Finally, results of volunteers’ rides were compared to results of a simulation with use a driver model based on fuzzy logic. This model, in the future, may be used in development of a car simulator equipped with ADAS.

PL

Obecnie zaawansowane systemy wspomagania kierowcy (ADAS) stają się coraz popularniejszym elementem wyposażenia samochodów. Z procesem ich rozwoju wiąże się konieczność przygotowania modeli numerycznych i przeprowadzenie testów symulacyjnych, aby zapewnić bezpieczne wdrożenie systemów. Z faktu ich bezpośredniego powiązania z interfejsem człowiek- maszyna wynika potrzeba prowadzenia testów na symulatorze z udziałem ochotników. Są one niezbędne do sprawdzenia poprawności działania danego systemu, ale przede wszystkim do wykazania różnic w działaniu systemu i kierowcy w kontekście niezawodności człowieka. Prezentowane badania pokazują wyniki testów symulatorowych w dwóch scenariuszach: pozamiejskim i mieszanym. Testy składały się z klasycznych zadań, w których kierowca musiał utrzymywać bezpieczną, z góry określoną odległość od wiodącego samochodu. W rezultacie wyniki eksperymentów porównano z osiągami samochodu referencyjnego, wyposażonego w tempomat adaptacyjny tzw. ACC (Adaptative Cruise Control). Umożliwiło to ocenę kierowcy pod kątem jego niezawodności. Ponadto do analizy obciążenia uczestników zastosowano również testy kwestionariuszowe NASA TLX. Ostatecznie wyniki przejazdów uczestników testów porównano także z wynikami symulacji przeprowadzonej z wykorzystaniem modelu wirtualnego kierowcy (zbudowanego z użyciem logiki rozmytej). Model ten w przyszłości będzie mógł być wykorzystany do opracowania i rozwoju symulatora samochodowego wyposażonego w ADAS.