Design and Dynamic Analysis of a Protection Structure of the Infrared Sensor

The vibration,electromagnetic wave and temperature shift of the satellite platform have a great impact on the imaging quality of space infrared sensor. In order to avoid those interruptions from outside,a protection structure of sensor was designed. Firstly,a new type material (Gr /Al composite) was applied to produce the shield cover of sensor,which not only had lighter weight,higher stiffness,but the function of electromagnetic shielding as well. Secondly,a rubber ring was employed to joint the sensor and its bracket forming a flexible suspension. Then,a novel method called variable coefficients of stiffness and damping was used for modelling the hysteretic damping of the flexible suspension and identifying its characteristic parameter. Establishing the mathematic equation of the system according to the result of parameter identification and acquiring the maximum acceleration of sensor centroid,which can reach 21. 32 m / s2 at the frequency of 155Hz. After the frequency of 325Hz,the transmissibility ratio would be less than 0. 5 and it was beneficial to isolate the vibration. Finally,compared the simulation result with vibration experiment and calculation, the maximum error was 5. 25% . It further proved the validity ofidentification and simulation. This protection structure has an important application value in the field of remote sensing.