Modal Analysis of GUARANI I Experimental Rocket
Kesiany Máxima de Souza1; Paulo Gabriel Cunha Martins1
1 Universidade de Brasília
doi:10.20906/CPS/CILAMCE2017-1116
Resumo
During a flight mission, the rocket is in a harsh environment with aerodynamic loads due to velocity itself. These loads and the motor propulsion excite the structure of the rocket. The force and frequencies acting depends on the state of the rocket, in other words, its velocity, the air density, angle of attack, and therefore it varies along the entire mission. The problem is that some frequencies of vibration can damage some parts of the rocket due to the resonance. For example, the communication hardware installed in the last stage during the mission, or some release of structural part due to the vibration that could cause a disaster [2]. Modal analysis is used to avoid resonance into engineering problems. Vibration can have severe implications on the structure of a rocket, therefore, it is important to know the vibration models of the rocket in order to better define the place of certain equipment and sensors inside it. This article deals with a modal analysis of GUARANI 1 experimental rocket. Some numerical simulations were performed in order to get the natural frequencies and vibration modes. These simulations were realized on the software Modal available on ANSYS and in the Engineering vibration toolbox for MATLAB [1]. For the simulations two cases were considered, the first one the rocket on its Launchpad before the launch, and the other were the rocket in its apogee, without fuel and with the Payload on board. To simulate on ANSYS, were considered all the rocket in CAD version, then it was simplified to accommodate well a mesh grid over all the rocket. The next and last step was the application of the boundary conditions of each case. The simulation on Engineering vibration toolbox were realized after for both cases. The rocket was divided into 27 parts to consider all the structural parts on each module, that is, propulsion, avionics and payload. In each division, it was required some properties to evaluate the natural frequencies and modal shapes. As results we have that from the 150 first modal shapes
Palavras-chave: Guarani 1; vibration; resonance; modal analysis