Design And Calibration Of A New Force Sensor

The steam generator is an extremely important heat exchange equipment in Nuclear Power Plant. But the most important part is the heat-transfer tube. Not only do it bears the larger temperature difference and the high pressure differential stress between the primary side and secondary side, but also, when it works regularly, the pipe will be rubbed and worn by the pipeline at the supporting point, which results in the tube wall become thinner so that the probability of SGTR's accident is higher. If the heat-transfer tube bursts, it can cause the leakage of radioactive substances, even make the reactor shutdown.In order to get the wear situation of the pipe wall, it needs to measure the longitudinal and radial vibration frequency of sensor and the vertical force and radial force. Besides, the vibration frequency and force is dynamic. However, the sensor must keep up with the measured tube from beginning to end so that it can get intact signal. Therefore, this paper designs an optical fiber force sensor which can measure the vibration frequency and strength changes in some extent as well as this sensor can never break away from the measured tube. Also, this sensor has some features that it's small, good immunity, light, high linearity and etc. It has a certain meaning and practical value that professors design and test this sensor as well as apply it into research.In this paper, firstly, it introduces the background and practical significance of the project work. Later on, it combines the development status of the dynamic measuring force sensor with the dynamic and static force sensor calibration system. And according to these theories, it demonstrates the important significance of the research on optical fiber pressure sensors.Secondly, the design scheme of sensor is based on real working conditions of sensor and according the structure mechanics model of sensor which is established by design scheme of sensor and measurement mode, it elicits relevant differential equation and transfer function, eventually it calculates the sensor vibration frequency range of 50 KHZ to 239 KHZ and the critical frequency of the sensor pipe out of touch is 398.062 KHZ. Then, it uses the MATLAB to calculate and paint the optimal structure of value of force sensor. Last step, it uses the ANSYS Workbench to make a statics analysis, under the influence of the range from 1N to 300 N of Static load, it can reach 0.03 mm, which is maximum deflection. And this value is in the range of measurement accuracy of sensor. Also, this paper makes the modal analysis of the structural beams. Through analyzing, the error of the simulative value and the theoretical calculation is 0.27%. So, this designed sensor is qualified.Thirdly, this paper introduces the corresponding performance index of the static calibration and dynamic test of the optical fiber pressure sensors. Later on, it designs, processes and fabricates the static calibration device, which verifies it is feasible in theory. According the forced oscillation method, it constructs the dynamic test model of the system by itself and starts from the static aspect, it elicits and calculates the coherence value of the force hammer standard signal and response signal of optical fiber pressure sensors, which is 1.05. And this proves the model is feasible. At last, this paper introduces the theories that they are used in signal processing and signal analysis.Fourthly, it researches the static calibration and dynamic test of the hardware system and software system. Besides, it uses C++ to write the driver of data collection. And through the platform of virtual instrument, the driver of data collection combines the LabVIEW to write the data processor, which can store the data, collect the data and analyze the signal.Finally, this paper sets up the static calibration and dynamic testing experiment platform of the optical fiber pressure sensors and analyzes the corresponding performance index. And draw the conclusion that there were linear between loading force and experiments. The sensor linearity is 0.22% and the static sensitivity is 1.0006. And the coherence value of the force hammer standard excitation signal and response signal of optical fiber pressure sensors, which is 0.9916. According the waveform of autocorrelation and cross-correlation between these two signals, the frequency difference is 1.18 HZ and the phase difference is 10 degree, from the dynamic aspect, it proves this sensor is fantastic, including the respond speed, the reaction speed, the performance and so on.In this paper, the research design and relevant subject has a certain important value for the structure design and calibration of the sensor. And for other types of load platform calibration system development and related technology and experimental study, it provides a reference as well as has some guiding significance for research of high precision load platform.