Research On High Frequency Vibratory Stress Relief Devices

This dissertation is supported by the National Natural Science Foundation of China—"Research on mechanism and related technology of multi-dimension, high-frequency and microcosmic VSR" (No.50305036). High-frequency VSR devices based on the Giant Magnetostrictive Material(GMM) were studied systematically both in theoretical analysis and experimental research. The dissertation consists of six chapters.In chapter 1, the background and significance of the research were introduced, and the current research situations on VSR at home and on aboard were summarized, and the limitation of studying on VSR was also introduced. Then the contents of this dissertation were proposed.In chapter 2, the principle of high-frequency VSR was analyzed in this paper. The essential method of adjusting and relieving residual stress was introduced on the basis of analyzing the mechanism of residual stress. From the view of stress-strain principle of the metal and micro-mechanics, the traditional VSR(low-frequency VSR) and high-frequency VSR were analyzed. High-frequency VSR will cover the shortage of traditional VSR by analyzing theirdifferences and be more significant to promote the wide application of VSR in our country.In chapter 3, the high-frequency actuator based on the GMM was analyzed. Firstly, the characteristics and mechanism of GMM were introduced. The driving principle of GMM actuator was analyzed, and then a kind of GMM actuator was manufactured utilizing the effect of GMM. Operating principle, structural design and magnetic circuit design of the actuator were also introduced. At last, magneto-mechanical model and dynamic model of the actuator were set up, and relations between the input current and the output force or between the output force and the additional mass were separately analyzed.In chapter 4, the driving power amplifier of high-frequency actuator was studied. At first, the characteristics of the driving power amplifier were introduced, and the overall design method of the driving power amplifier was put forward, and then constant-current source circuit and power amplifier circuit of current feed-back were developed separately. An experiment on power amplifier system was also carried out, including characteristic of constant-current and distortion of output current. The results show that the system performance coincides with the design criterion.In chapter 5, the device of high-frequency VSR was tested, including the high-frequency actuator and driving power amplifier. The experimental results proved the theoretical solutions in chapter 3. Then a series of experiments on the welded specimens were carried out by utilizing the related equipment. The results between before the VSR and after the VSR were measured by the sophisticated blind hole method, which proved the feasibility of the VSR; At the same time, according to the above results, a new kind of evaluation method based on the D-Markov model algorithm used in the process of high-frequency VSR was put forward.In chapter 6, all achievements of the dissertation were summarized and the further research work, which will be done from now on, was put forward.