Análise de lesões decorrentes de impactos com capacetes

Mestrado em Engenharia MecânicaNeste trabalho efetua-se uma avaliação do desempenho de um capacete rodoviário já comercializado e aprovado pela maioria das normas de segurança atuais. Este desempenho é avaliado através da reprodução fidedigna de impactos semelhantes aos que ocorrem comumente em acidentes reais, onde ambos os movimentos, translacionais e rotacionais estão presentes. Duas validações foram realizadas por comparação com resultados experimentais: uma relativa ao modelo constitutivo do poliestireno expandido, que integra a camada de absorção de energia do capacete e outra relativa aos valores das acelerações do centro de gravidade da cabeça após os impactos definidos pela norma de segurança ECE R22. Após validação, um impacto oblíquo foi simulado e os resultados foram comparados com os valores limites de traumatismo craniano, a fim de prever as lesões na cabeça resultantes de acelerações rotacionais, não previstas na norma referida. A partir desta comparação, concluiu-se que lesões cerebrais, tais como concussão e lesão axonal difusa podem ocorrer mesmo com um capacete rodoviário que foi aprovado pela maioria das normas atuais, e apenas replicando um impacto que vulgarmente é observado em colisões reais. As mesmas lesões foram previstas após avaliação das lesões num impacto da norma ECE R22 com uma cabeça biomecânica modelada em elementos finitos. As conclusões apontam para uma recomendação assertiva no sentido de que os efeitos decorrentes de desacelerações rotacionais devem também ser contemplados pelas normas de segurança vigentes e que os procedimentos de teste actuais devem ser melhorados, especialmente a cabeça de teste, a qual não é capaz de prever lesões, para promover a segurança entre os motociclistas.In this work it is carried out the performance assessment of a motorcycle helmet, approved by the majority of current standards and already placed on the market. The evaluation is based on accurate reproduction of impacts that are similar to the ones that commonly occur in real crashes, where both motions, translational and rotational are considered. The numerical framework is validated against two di erent set of experimental results. The first concerns the constitutive model of the expanded polystyrene, the material responsible for energy absorption during impact; the second related to the head's centre of mass acceleration after the impacts de ned in the European ECE R22 standard. Both were validated against experimental data. Doing so, an oblique impact was simulated and the results were compared against head injury thresholds in order to predict the resultant head injuries. From this comparison, it was concluded that brain injuries such as concussion and di use axonal injury can occur even with a helmet that was approved by the majority of the helmet standards, that unfortunately do not contemplate rotational components of acceleration. The same lesions were predicted after assessing injuries resulting from an impact de ned by the ECE R22 standard with a biomechanical FE head model. At the end, conclusion points out a strong recommendation on the necessity of including rotational motion in forthcoming motorcycle helmet standards and improving the the actual test procedures, especially the test headform, which is not able to predict lesions, to improve the safety between the motorcyclists

Vehicle and Traffic Safety

The book is devoted to contemporary issues regarding the safety of motor vehicles and road traffic. It presents the achievements of scientists, specialists, and industry representatives in the following selected areas of road transport safety and automotive engineering: active and passive vehicle safety, vehicle dynamics and stability, testing of vehicles (and their assemblies), including electric cars as well as autonomous vehicles. Selected issues from the area of accident analysis and reconstruction are discussed. The impact on road safety of aspects such as traffic control systems, road infrastructure, and human factors is also considered

Aeronautical engineering: A continuing bibliography with indexes (supplement 301)

This bibliography lists 1291 reports, articles, and other documents introduced into the NASA scientific and technical information system in Feb. 1994. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Advances in Rotating Electric Machines

It is difficult to imagine a modern society without rotating electric machines. Their use has been increasing not only in the traditional fields of application but also in more contemporary fields, including renewable energy conversion systems, electric aircraft, aerospace, electric vehicles, unmanned propulsion systems, robotics, etc. This has contributed to advances in the materials, design methodologies, modeling tools, and manufacturing processes of current electric machines, which are characterized by high compactness, low weight, high power density, high torque density, and high reliability. On the other hand, the growing use of electric machines and drives in more critical applications has pushed forward the research in the area of condition monitoring and fault tolerance, leading to the development of more reliable diagnostic techniques and more fault-tolerant machines. This book presents and disseminates the most recent advances related to the theory, design, modeling, application, control, and condition monitoring of all types of rotating electric machines

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 375)

This bibliography lists 212 reports, articles, and other documents recently introduced into the NASA Scientific and Technical Information System database. Subject coverage includes the following: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018