Reliability Evaluation And Research On35CrMo Valve Shaft Based On Fuzzy Mathematics And Grey System Theory

Valve is a critical equipment in conveying system of gas, steam, liquid and chemicalmaterial. Hence, the failure of valve will directly result in the paralysis of conveyingsystem, which may affect the normal order of production, living, and even cause severeloss of life and damage of property.The valve shaft is the key part to the quality and reliability of valve. Using35crmovalve shaft as the research object, this thesis is aiming to build the reliability evaluationmethod of valve shaft, to develop the related evaluation software, and to verify the resultsof experiment. In this topic, the authors have finished related research as follows:In view of that there are many uncertainties and many factors may affect thereliability of the valve shaft quality, it is difficult to use the traditional technology andmethods to judge the problem, the authors determined to select fuzzy and greymathematical theory to evaluate the quality of the valve shaft reliability, and in thisway,successfully solve the disadvantages of traditional methods in the analysis ofreliability.Based on the analysis of factors affecting reliability of valve shaft quality and theintroduction of fuzzy mathematics and grey system theory, the authors establishedcomprehensive evaluation model of the valve shaft reliability and determined the weightvalue of the evaluation index in the evaluation system.According to the established evaluation model, the authors used VB to write areliability evaluation software of valve shaft based on the theory of the fuzzy mathematicsand grey system theory and verified the data of experiment.By using the above theory and evaluation model, the authors completed the evaluationof reliability instance of35crmo valve shaft, especially the mechanical properties, physicalproperties, chemical properties, and problems arising from the evaluation are analyzed andimproved to obtain a better evaluation result. This topic is a research on reliability of the valve shaft quality evaluation indexsystem, the degree of influence and weight value, And the authors explored the feasibilityof fuzzy grey theory in quality reliability evaluation of axial product, which is helpful topromote the engineering application of the method.