Comparative Vibration Analysis Of A Slender Beam In Gravity Compensation Test And Zero-gravity Environment

The Space Station mission requires an extensive engineering study before a manned mission can be put into space. Since the dynamic behavior of an entire assembly cannot be tested on earth, computer models are used as an engineering tool to predict what will happen in space. this work aims to improve the mathematics model for determining the first natural frequency of a slender beam in zero-gravity environment, it can help engineers to understand the behavior of a beam in space.The research focus on a model containing a 4-meter-long slender beam fixed to the ground at one end and a concentrated mass at the other end, which represents one element of a space arm. The research content include:1)Modeling the element of space arm in zero-gravity environment using Distributed-Parameter Models. The 4-meter-long slender beam fixed on one end should be modeled as flexible so that we could analyze its vibration.2) Modeling the element of space arm in gravity compensation environment using Distributed-Parameter Models. The 4-meter-long slender beam has one of its end fixed to the ground, and was under constraint of external gravity compensation forces. These factor should be modeled as constraints.3)Comparing the two modeled in 1) and 2), and analyze the difference between the free response under external impact, especially the free response around natural frequency.4)Establish Model in Software and verity the analyze carried on in 1) 、2)and 3).Theoretical model describes the first natural frequency of a slender beam. The major issues in the beam develop ment are: determine the governing differential equation, obtaining the eigenfunctions from governing equation. These issues apply to both Euler-Bernoulli and energy transfer theories.The main techniques of dynamic beam analysis can be divided into continuous and discrete methods. The most popular discrete method for dynamic beam analysis is the Finite Element Method(FEM). FEM is used to simulate the behavior of a slender beam like at the test time. Using ANSUS Workbench software with normal mode analysis technique is applied to simulate the beam behavior due to dynamics vibration.This work provide to find new mathematics model to calculation the first natural frequency of a slender beam. This model will contribute to promote the vibration analysis of a beams on gravity compensation test and in Space.Calculation of displacement and the first natural frequency of a slender beam, in gravity compensation test and in zero-gravity environment, done with help of MAPLE 11 and ANSYS 14.5 software package.