1 |
Biomechanická reflexe cervikokraniální oblasti při frontálním nárazu / Biomechanical reflection of the cervicocranial part during frontal impactKozel, Jakub January 2012 (has links)
Title: Biomechanical reflection of the cervicocranial part during frontal impact Objectives: The aim of the work was to analyze in which parameters differs ATD from human participant during frontal impact. Characterize the head movement, compare maximal post impact head speed between ATD and human volunteers and defereneces between volunteer with eye control and without. Methods: Measuring was done with 8 volunteers and ATD (Manikin, 50th percentile man). For each volunteer were done two measurements, first without eye control and second with eye control. ATD was measured twice. It was recorded by Qualisys system, specifically by three optical cameras, on crash simulator. Results were processed in Qualisys Track Manager. There were tracked three markers, two on the body - forehead, shoulder and one on the sledge. Results: Results showed that speed of the head depends on eye control. Volunteer without eye control had higher post impact speed of head (4,94 m/s) than ATD (3,67 m/s) and volunteer with eye contact (3,19 m/s). Quite the same result was observed in change of distance between head and sledge after impact. There was higher value for volunteer without eye contact than for ATD. Keywords: Whiplash, frontal impact, Qualisys, crash simulator, cervicocranial part
|
2 |
DETEKCE BIOMECHANICKÉ ODEZVY HLAVY NA EXTRÉMNÍ ZÁTĚŽ / Detection of head biomechanical response during extreme loadingFanta, Ondřej January 2014 (has links)
CHARLES UNIVERSITY IN PRAGUE Faculty of Physical Education and Sport Dissertation thesis March 2014 Ondřej Fanta ABSTRACT Title: Detection of head biomechanical response during extreme loading Objectives: The aim of the work was to monitor the current state of knowledge on the issue of closed head injuries, in contact and contactless respectively impacts, to establish appropriate biomechanical indicators for the detection and analysis of internal mechanical response under external mechanical load and to assess the specific circumstances that may affect the resulting injury criteria especially with regard to the actual reaction of the organism before impact. Methods: To the processing research were included and cited in particular impacted world-class publications and bibliography in the number of more than 80sources. The measurements and analysis of contact impacts were taken on the constructed impactor and the analysis of the contactless collisions were taken on the impacts simulator. The monitored biomechanical values were in particularly kinematic data describing the movement of the head towards the neck, values of acceleration of the head, head injury criteria and activity of selected muscles of the neck. Results: It consists diagram of the process of head injury and analysis of two main branches -...
|
3 |
Influence de l’âge et du morphotype sur la réponse mécanique du thorax : étude expérimentale in vivo et analyse numérique à l'aide de modèles EF personnalisés du corps humain / Age and morphotype influence on thoracic mechanical response : in vivo experimental study and numerical analysis using personalized human body FE modelsPoulard, David 19 December 2012 (has links)
Cette étude aborde le problème de l’aggravation du risque de fractures de côtes chez les automobilistesâgés en choc frontal. L’analyse de la bibliographie fait ressortir que les moyens actuels d’évaluationdu risque de fractures ne permettent pas de prendre en compte les différences anatomiques et depropriétés mécaniques du thorax observées chez les personnes âgées. Les modèles éléments finis (EF)personnalisés du corps humain offrent un grand potentiel en tant qu’outil avancé d’évaluation durisque de blessures. Toutefois, des données expérimentales sont nécessaires pour valider ces modèlesdans des conditions réalistes. De plus, le choix du niveau de personnalisation et la sensibilité de laréponse du modèle à celle-ci doivent être évaluées.Des expérimentations in vivo menés sur des volontaires ceinturés en choc léger, de différents âges etanthropométries, ont été réalisées. Ces tests ont permis d’étudier l’influence de l’âge et de lacorpulence sur la réponse mécanique du thorax et ont permis l’obtention de corridors nécessaires à lavalidation de modèles EF personnalisés. La géométrie du modèle numérique THUMS a été adaptée àcelle des volontaires et les propriétés mécaniques du thorax ont été modifiées au vu du vieillissementpour effectuer une analyse similaire dans le domaine lésionnel. Les simulations numériques ont mis enévidence un risque accru de fracture de côtes pour certains modèles personnalisés.Cette étude devrait permettre de mieux estimer le risque de blessure pour les automobilistesvulnérables. Elle devrait contribuer ainsi à promouvoir les modèles personnalisés du corps humaincomme outil avancé d’évaluation du risque de blessures. / This study deals with the topic of increased risk of rib fractures among elderly drivers infrontal impact. The analysis of the literature reveals that actual thorax injury assessment tools do nottake into account for the differences in anatomical features and biological material properties observedbetween adults and elderly. Personalized human body finite element (FE) models have great potentialas improved thorax injury assessment tools. However, experimental data are needed to validate thesemodels under real-world conditions. In addition, the choice of the level of personalization of the modeland the sensibility of the model response to this personalization must be assessed to predict thoracicinjury risk.In vivo sled tests were performed on belted volunteers of various anthropometries and age. These testswere used to assess the influence of age and corpulence on thorax mechanical response and allowed toobtain corridor responses needed to validate personalized FE models. The geometry of the FE modelTHUMS was adapted to the volunteers and the thorax material properties were modified consideringaging to carry out a similar analysis in the injurious domain. Numerical simulations highlighted anincreased risk of rib fractures for specific personalized models.This study should help to better estimate the injury risk for car occupants. It should contribute topromote personalized human body models as attractive thorax injury assessment tool ofvulnerable individuals.
|
4 |
The Development of an Analytical Model to Predict Thoracic Response from Dynamic Individual Rib TestsSreedhar, Akshara January 2021 (has links)
No description available.
|
5 |
DETEKCE BIOMECHANICKÉ ODEZVY HLAVY NA EXTRÉMNÍ ZÁTĚŽ / Detection of head biomechanical response during extreme loadingFanta, Ondřej January 2014 (has links)
CHARLES UNIVERSITY IN PRAGUE Faculty of Physical Education and Sport Dissertation thesis March 2014 Ondřej Fanta ABSTRACT Title: Detection of head biomechanical response during extreme loading Objectives: The aim of the work was to monitor the current state of knowledge on the issue of closed head injuries, in contact and contactless respectively impacts, to establish appropriate biomechanical indicators for the detection and analysis of internal mechanical response under external mechanical load and to assess the specific circumstances that may affect the resulting injury criteria especially with regard to the actual reaction of the organism before impact. Methods: To the processing research were included and cited in particular impacted world-class publications and bibliography in the number of more than 80sources. The measurements and analysis of contact impacts were taken on the constructed impactor and the analysis of the contactless collisions were taken on the impacts simulator. The monitored biomechanical values were in particularly kinematic data describing the movement of the head towards the neck, values of acceleration of the head, head injury criteria and activity of selected muscles of the neck. Results: It consists diagram of the process of head injury and analysis of two main branches -...
|
6 |
Development of a new test methodology for car-to-truck crashBuzys, Matas, Nilsson, Sara January 2019 (has links)
Till följ av de stora skadorna som riskeras vid frontalkollision mellan personbil och lastbil, utför Scania CV AB kraschtester för att bättre kunna utveckla komponenter med syfte att skydda passagerarna i personbilen. Den typ av test som denna studie bygger på utvärderar den s.k. FUP:en (engelska Front Underrun Protection). I dagsläget görs ett fullskaligt test, där en personbil avfyras in i en lastbil. Syftet med studien är att undersöka möjligheten att utveckla en förenklad test metod där endast de väsentliga komponenterna från lastbilen inkluderas, och en representativ struktur ersätter personbilen. Om möjligt kommer detta minska kostnaderna samt möjliggöra för större repeterbarhet. Tester och utvärderingar görs med hjälp av simulationer i LS-Dyna, ANSA & META, och designkoncept visualiseras i CAD-programmet CATIA V5. Resultat visar att det finns goda förutsättningar för att ersätta personbilen med en barriär av honeycomb struktur samt att lastbilen kan ersättas med en vagn där de väsentliga komponenterna fäst. Diskussioner kring simuleringarna och designen lyfter fram faktorer som visar på goda utvecklingsmöjligheter, men med betoning på det fortsatta arbetet som krävs. / Scania CV AB are developing components to prevent fatal damages during frontal collisions with passenger cars. Therefore, they need to test their assemblies and specifically FUP (Frontal Underrun Protection). Currently, a full-scale test is done in which a passenger car is launched into a truck. The purpose of this study is to examine and develop the possibility of having a simplified test procedure in which only the relevant components of the truck are included, and a representative structure replaces the car. If possible, this would reduce costs and allow for greater repeatability. Analysis and evaluations are done via finite element models using ANSA, LS-Dyna and META. The conceptual design is visualized using CATIA V5. Results show good indication that the passenger car can be replaced by a trolley with deformable barriers mounted on it and the truck can be replaced by a simplified structure with main FUP components mounted onto it. Discussions about the numerical models results and the conceptual design highlight factors that show promising possibilities, but with emphasis on the continued work that is required.
|
7 |
Aspectos relacionados com o impacto semi-frontal em ônibus rodoviárioGoedel, Fábio January 2013 (has links)
O comportamento estrutural de veículos de transporte coletivo, quando submetido a eventos de impacto, é de grande relevância na engenharia automobilística, pois principalmente o ônibus, vem se tornando um dos meios de transporte de elevada importância, sendo que seu uso vem aumentando a cada ano. No entanto, as estruturas de ônibus que circulam nas estradas brasileiras não são capazes de resistir, sem causar danos aos passageiros, a eventos de impacto em acidentes, o que pode ser verificado em pesquisas divulgadas pela Agência Nacional de Transportes Terrestres (ANTT) em 2007, que mostra a evolução de acidentes e vítimas envolvendo ônibus, que cada ano aumentam consideravelmente. Neste contexto, pretende-se desenvolver um absorvedor de impacto que aumente a capacidade de absorção da energia de impacto e evite a invasão da região de sobrevivência dos passageiros, e desta forma diminuindo o número de vítimas em acidentes. Serão abordados neste trabalho eventos de impacto semi-frontal, justificado pela gravidade dos acidentes desse tipo nas estradas, sendo este o tipo de acidente que deixa um maior número de vítimas, pois geralmente parte da estrutura lateral do ônibus é removida, expondo os passageiros no período de impacto. Esse efeito é conhecido como “Efeito Abridor de Latas”. O modelo numérico deste trabalho será formado por elementos unifilares, sendo a estrutura do ônibus formada por vigas flexíveis e/ ou rígidas, unidas através de juntas não lineares rotacionais e translacionais. A rigidez de cada junta não linear é obtida a partir de métodos analíticos que descrevem o comportamento do tubo de parede fina quando submetido a impacto. / The structural behavior of transportation vehicles when subjected to events of impact is of great relevance in automotive engineering, mainly because the bus has become a highly important alternative means of transportation, and its use is increasing every year. However, the structures of the buses circulating on Brazilian roads are not able to withstand strong impact, without causing passengers’ injury in events where accidents occur, which can be shown in surveys released by the National Transport Agency (ANTT) in 2007, presenting that the great incidence of accidents with victims involving buses is increasing considerably every year. In this context, the development of an impact absorber that had the capability to increase the impact energy absorption and prevent the invasion of part of bus on the region where passengers are located (reducing the number of fatalities in accidents) are the objectives of this work. In this work, a semi-frontal impact will be presented and studied due to the severity of such accident, as the side of the bus structure is removed, exposing the passengers during the impact. This is the effect known as “Can opener effect”. The numerical model of this study will consist of a single-wire element, with a bus structure formed by flexible and/or rigid beams joined by nonlinear rotational and translational joints. The rigidity of each nonlinear joint is obtained by analytical methods describing the behavior of a thin-walled tube subjected to an impact force.
|
8 |
Aspectos relacionados com o impacto semi-frontal em ônibus rodoviárioGoedel, Fábio January 2013 (has links)
O comportamento estrutural de veículos de transporte coletivo, quando submetido a eventos de impacto, é de grande relevância na engenharia automobilística, pois principalmente o ônibus, vem se tornando um dos meios de transporte de elevada importância, sendo que seu uso vem aumentando a cada ano. No entanto, as estruturas de ônibus que circulam nas estradas brasileiras não são capazes de resistir, sem causar danos aos passageiros, a eventos de impacto em acidentes, o que pode ser verificado em pesquisas divulgadas pela Agência Nacional de Transportes Terrestres (ANTT) em 2007, que mostra a evolução de acidentes e vítimas envolvendo ônibus, que cada ano aumentam consideravelmente. Neste contexto, pretende-se desenvolver um absorvedor de impacto que aumente a capacidade de absorção da energia de impacto e evite a invasão da região de sobrevivência dos passageiros, e desta forma diminuindo o número de vítimas em acidentes. Serão abordados neste trabalho eventos de impacto semi-frontal, justificado pela gravidade dos acidentes desse tipo nas estradas, sendo este o tipo de acidente que deixa um maior número de vítimas, pois geralmente parte da estrutura lateral do ônibus é removida, expondo os passageiros no período de impacto. Esse efeito é conhecido como “Efeito Abridor de Latas”. O modelo numérico deste trabalho será formado por elementos unifilares, sendo a estrutura do ônibus formada por vigas flexíveis e/ ou rígidas, unidas através de juntas não lineares rotacionais e translacionais. A rigidez de cada junta não linear é obtida a partir de métodos analíticos que descrevem o comportamento do tubo de parede fina quando submetido a impacto. / The structural behavior of transportation vehicles when subjected to events of impact is of great relevance in automotive engineering, mainly because the bus has become a highly important alternative means of transportation, and its use is increasing every year. However, the structures of the buses circulating on Brazilian roads are not able to withstand strong impact, without causing passengers’ injury in events where accidents occur, which can be shown in surveys released by the National Transport Agency (ANTT) in 2007, presenting that the great incidence of accidents with victims involving buses is increasing considerably every year. In this context, the development of an impact absorber that had the capability to increase the impact energy absorption and prevent the invasion of part of bus on the region where passengers are located (reducing the number of fatalities in accidents) are the objectives of this work. In this work, a semi-frontal impact will be presented and studied due to the severity of such accident, as the side of the bus structure is removed, exposing the passengers during the impact. This is the effect known as “Can opener effect”. The numerical model of this study will consist of a single-wire element, with a bus structure formed by flexible and/or rigid beams joined by nonlinear rotational and translational joints. The rigidity of each nonlinear joint is obtained by analytical methods describing the behavior of a thin-walled tube subjected to an impact force.
|
9 |
Aspectos relacionados com o impacto semi-frontal em ônibus rodoviárioGoedel, Fábio January 2013 (has links)
O comportamento estrutural de veículos de transporte coletivo, quando submetido a eventos de impacto, é de grande relevância na engenharia automobilística, pois principalmente o ônibus, vem se tornando um dos meios de transporte de elevada importância, sendo que seu uso vem aumentando a cada ano. No entanto, as estruturas de ônibus que circulam nas estradas brasileiras não são capazes de resistir, sem causar danos aos passageiros, a eventos de impacto em acidentes, o que pode ser verificado em pesquisas divulgadas pela Agência Nacional de Transportes Terrestres (ANTT) em 2007, que mostra a evolução de acidentes e vítimas envolvendo ônibus, que cada ano aumentam consideravelmente. Neste contexto, pretende-se desenvolver um absorvedor de impacto que aumente a capacidade de absorção da energia de impacto e evite a invasão da região de sobrevivência dos passageiros, e desta forma diminuindo o número de vítimas em acidentes. Serão abordados neste trabalho eventos de impacto semi-frontal, justificado pela gravidade dos acidentes desse tipo nas estradas, sendo este o tipo de acidente que deixa um maior número de vítimas, pois geralmente parte da estrutura lateral do ônibus é removida, expondo os passageiros no período de impacto. Esse efeito é conhecido como “Efeito Abridor de Latas”. O modelo numérico deste trabalho será formado por elementos unifilares, sendo a estrutura do ônibus formada por vigas flexíveis e/ ou rígidas, unidas através de juntas não lineares rotacionais e translacionais. A rigidez de cada junta não linear é obtida a partir de métodos analíticos que descrevem o comportamento do tubo de parede fina quando submetido a impacto. / The structural behavior of transportation vehicles when subjected to events of impact is of great relevance in automotive engineering, mainly because the bus has become a highly important alternative means of transportation, and its use is increasing every year. However, the structures of the buses circulating on Brazilian roads are not able to withstand strong impact, without causing passengers’ injury in events where accidents occur, which can be shown in surveys released by the National Transport Agency (ANTT) in 2007, presenting that the great incidence of accidents with victims involving buses is increasing considerably every year. In this context, the development of an impact absorber that had the capability to increase the impact energy absorption and prevent the invasion of part of bus on the region where passengers are located (reducing the number of fatalities in accidents) are the objectives of this work. In this work, a semi-frontal impact will be presented and studied due to the severity of such accident, as the side of the bus structure is removed, exposing the passengers during the impact. This is the effect known as “Can opener effect”. The numerical model of this study will consist of a single-wire element, with a bus structure formed by flexible and/or rigid beams joined by nonlinear rotational and translational joints. The rigidity of each nonlinear joint is obtained by analytical methods describing the behavior of a thin-walled tube subjected to an impact force.
|
10 |
Caractérisation du sous-marinage chez l'occupant de véhicule en choc frontal / Investigation of car occupants submarining in frontal impactsLuet, Carole 27 September 2013 (has links)
Le sous-marinage, apparaissant lorsque la ceinture pelvienne glisse au-dessus des épines iliaques antérosupérieures (E.I.A.S.) du bassin, est la cause principale des lésions abdominales sévères. Ce phénomène, conditionné par l’angle relatif entre la ceinture pelvienne et le bassin, est fortement lié à la cinématique du bassin au cours du choc. Cette dernière dépend des efforts et moments qui y sont appliqués, provenant principalement de la colonne lombaire, des hanches, du contact avec l’assise du siège ainsi que de la ceinture pelvienne. L’objectif est de caractériser le comportement de la population au regard du sousmarinage. Cela passe par l’identification des paramètres individuels influents sur le phénomène et par l’étude de leur distribution sur la population. Pour cela, neuf essais sur sujets humains post-mortem (S.H.P.M.) ont été effectués dans un environnement simplifié. Trois configurations de choc, chacune testée sur trois sujets, ont été définies. Les résultats ont ensuite servi de base pour la validation d’un modèle éléments finis d’être humain. Le modèle a été amélioré de façon globale vis-à-vis des corridors définis par les réponses S.H.P.M. et personnalisé au niveau de la géométrie, de la répartition des masses et du comportement de la colonne lombaire pour correspondre à chacun des neuf sujets. La personnalisation de ces paramètres a permis de reproduire les comportements observés en essais. Enfin, le modèle a été utilisé dans une étude numérique pour approfondir la compréhension de la cinématique du bassin, d’une part, et identifier les paramètres individuels influençant le sous-marinage, d’autre part. La répartition des masses, la raideur de la colonne lombaire et l’orientation initiale du bassin influencent l’apparition du sous-marinage. L’ouverture des ailes iliaques, la position des E.I.A.S par rapport au point H, la profondeur de l’échancrure iliaque et l’épaisseur des tissus entre le bassin et la ceinture jouent aussi un rôle. / Submarining occurs in frontal crashes when the lap belt slides over the anterior superior iliac spine (ASIS) and is the principal cause of AIS 3+ abdominal injuries. Submarining is the consequence of the pelvis kinematics relative to the lap belt, driven by the equilibrium of forces and moments applied to the pelvis. The four main components playing a role in the pelvis kinematics are the lumbar spine, the hips, the seat pan and the lap belt. The purpose is to characterize the population behavior regarding submarining. This requires to identify individual parameters having an effect on submarining and to examine their distribution among the population. A nine post-mortem human subject (PMHS) sled test campaign was carried out on a simplified environment. Three test configurations were defined. Each configuration was realized on three PMHS. The test results were used as reference data for a human finite element model validation. The model was improved to better fit the PMHS corridor responses and then personalized regarding the geometry, the mass distribution and the lumbar spine behavior to obtain nine models matching each PMHS. The personalized models responses were consistent with the PMHS ones. Finally, the human model was used in a numerical study. The numerical study was aimed at deepen the understanding of the pelvis kinematics on the one hand, and investigate the influence of several individual parameters on submarining on the other hand. The mass distribution, the lumbar spine stiffness and the initial pelvis orientation have revealed an influence on the submarining observation. The iliac wing angle, the position of the ASIS relative to the H-point, the iliac notch depth and the thickness of the soft tissues between the pelvis and the lap belt were also identified to have an effect on submarining.
|
Page generated in 0.0619 seconds