Based On Modal Analysis Of The Laser Plate Thickness Measuring Instrument Mobile Frame Structure Optimization Study

In the measurement process of high-accuracy laser measurement, the vibration of instrument is a key factor which influences the accuracy. The system's vibration comes from inner and outside, directly affects the relative position of the laser. To design a high accuracy C shape measurement instrument, the vibration characteristics such as natural frequency, modes shape must be obtained. Based on the experimental mode analysis, this paper focused on mode analysis and optimization of the vibration response of the C shape measurement instrument to search for the most suitable structure, which are as follows:1. With the result of the vibration experiment, the character of C shape frame is concluded. And through the working environment experiment, the excitement condition is confirmed.2. From the static FEA(Finite Element Analysis) of the strength and stiffness of C shape moving frame, the effect by the rib is made clear. A dynamic model is established to simulate the character of real structure, through the characteristics such as mode test, the natural frequency, mode shape is gained, which has verified the correctness of the finite element model.3. After the the FEA of the nature frequency and the mode shape, compared with the field test results, the main modes which should be avoided are selected. Through harmonic analysis, the response aplitude vs. frequency curve within 0 to 300Hz is calculated, and the conclusion that the response to lower frequency is relatively bigger than to higher frequency, thus the objective to improve the nature frequency.4. By the simulation and optimization through FEA software-ANSYS, the goal to avoid resonant vibration and increase the stability is realized. Combined with the C-shape frame working environment, after PSD spectrum and optimum design, After sensitivity analysis, the main design parameters which have more influence on optimization is selected, on this basis a structure which response less to the environment is gained through the further optimization, thus the measurement precision of the instrument is assured.The calculation and theoratical analysis is closely linked to the test and design of the C-shape frame, which contains great value in practical engineering, and reference value for other similar structure design and optimimun design.