Publication: Análisis a fatiga del chasis de la motocicleta MotoStudent debido a las fuerzas del motor
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2011-07
Defense date
2011-07-26
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Abstract
El objetivo del proyecto es predecir la resistencia a fatiga del chasis de la motocicleta MotoStudent debida a las fuerzas provocadas por el funcionamiento del motor. La motocicleta ha sido creada en la Universidad Carlos III de Madrid para presentarla al concurso MotoStudent. Para conseguir este propósito, ha sido necesario realizar otros estudios anteriores. El primer reto planteado para la resolución del trabajo, es la familiarización con un nuevo software de modelado y análisis de elementos finitos incorporado recientemente en la universidad, llamado ProEngineer Wildfire 5.0. Dicho software permite realizar modelados de piezas, ensamblajes de conjuntos, simulaciones con motores, simulaciones con fuerzas y otros diversos análisis. En primer lugar, se han modelado las piezas correspondientes a la parte alternativa del motor. Para ello, se ha partido de planos correctamente acotados. Una vez modeladas las piezas, se ha procedido a su ensamblaje. Para realizar el ensamblaje, ha sido necesario tener en cuenta la posibilidad de reproducir el movimiento alternativo característico de un motor de combustión interna. En segundo lugar, una vez se ha realizado correctamente el ensamblaje de las piezas, se ha procedido a calcular las fuerzas provocadas por el motor. Debido a que se trata de un motor de combustión interna, ha sido necesario crear una curva de presión correspondiente a la explosión del combustible en el interior del ciclindro. Para ello, se ha introducido una tabla con los valores de presión en función de los grados del cigüeñal. Además, ha sido necesaria la definición de condiciones iniciales, coeficientes de rozamiento entre las distintas partes del motor y sus propiedades de masa. Con esto, se ha simulado el movimiento del motor, obteniendo el valor de las fuerzas sobre el cigüeñal. A continuación, se ha procedido al estudio del chasis de la motocicleta. Para ello, se han localizado los puntos sobre los que está apoyado el motor; puntos sobre los cuales actúan las fuerzas anteriormente calculadas. Se han definido, por otro lado, las restricciones de la misma, teniendo en cuenta la posición del chasis en su montaje final. Por último, se han determinado dos tipos de análisis; uno estático y otro a fatiga. Como primer paso, en el análisis estático se ha calculado la resistencia del motor tal y como si la carga fuera estacionaria. A partir de los datos de resistencia estáticos, se ha procedido a realizar el cálculo a fatiga. Los resultados obtenidos han sido satisfactorios, ya que, tomando como vida infinita un valor de un millón de ciclos, se ha obtenido un coeficiente de seguridad de valor 2. En los resultados, se ha podido observar, además, los esfuerzos a los que se encuentran sometidas las distintas zonas del chasis, observándose las mayores tensiones en las soldaduras. ___________________________________________________________________________________________________________________
The main focus for this Project is to predict fatigue strength of MotoStudent motorcycle chassis due to forces caused by the engine motion. The motorcycle has been created in Carlos III University of Madrid in order to enter to MotoStudent competition. To achieve this purpose, it has been necessary to carry out previous studies. The first gap to resolve is to familiarize oneself with a new design and finite elements analysis software, recently incorporate to the university, called ProEngineer Wildfire 5.0. This software allows you to carry out part modeling, assemblies, engine and force simulations and very different analysis. In the first place, parts from the alternative part from the engine have been modeled. To do it, we have their planes correctly delimited. Once the parts are modeled, the assembly has been cerated. To do it, it has been necessary to have into account the possibility of reproducing the alternative movement that characterizes the internal combustion engines. In the second place, once assembly has been created correctly, we have calculated forces caused by the engine. Due to the engine is an internal combustion engine, it has been necessary to create a pressure curve, which shows the pressure inside the cylinder. To do it, a table relating pressure and crank angle, has been introduced in ProEngineer. Moreover, it has been defined initial conditions, friction coefficients between engine parts with relative movement, and mass properties. Finally, we have obtained forces acting over the crankshaft. Following, it has been carried out the study of motorcycle chassis. For it, we have located points where engine leans on, points on which forces previously calculated act and we have defined constraints. Finally, we have carried out two different analyisi; a static and a fatigue one. In the static analysis it has been calculated engine strength to a stable load. Based on static results, fatigue analysis has been carried out. The results obtained have been successful, since taking into account an infinite life as one million cycles, we have reached a safety factor of 2. Moreover, ProEngineer let us to observe different parts strain, noticing the highest strains on welds.
The main focus for this Project is to predict fatigue strength of MotoStudent motorcycle chassis due to forces caused by the engine motion. The motorcycle has been created in Carlos III University of Madrid in order to enter to MotoStudent competition. To achieve this purpose, it has been necessary to carry out previous studies. The first gap to resolve is to familiarize oneself with a new design and finite elements analysis software, recently incorporate to the university, called ProEngineer Wildfire 5.0. This software allows you to carry out part modeling, assemblies, engine and force simulations and very different analysis. In the first place, parts from the alternative part from the engine have been modeled. To do it, we have their planes correctly delimited. Once the parts are modeled, the assembly has been cerated. To do it, it has been necessary to have into account the possibility of reproducing the alternative movement that characterizes the internal combustion engines. In the second place, once assembly has been created correctly, we have calculated forces caused by the engine. Due to the engine is an internal combustion engine, it has been necessary to create a pressure curve, which shows the pressure inside the cylinder. To do it, a table relating pressure and crank angle, has been introduced in ProEngineer. Moreover, it has been defined initial conditions, friction coefficients between engine parts with relative movement, and mass properties. Finally, we have obtained forces acting over the crankshaft. Following, it has been carried out the study of motorcycle chassis. For it, we have located points where engine leans on, points on which forces previously calculated act and we have defined constraints. Finally, we have carried out two different analyisi; a static and a fatigue one. In the static analysis it has been calculated engine strength to a stable load. Based on static results, fatigue analysis has been carried out. The results obtained have been successful, since taking into account an infinite life as one million cycles, we have reached a safety factor of 2. Moreover, ProEngineer let us to observe different parts strain, noticing the highest strains on welds.
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Tecnología automovilística, Motocicletas, Mecánica de sólidos