Statistical Analysis On Fatigue State Of Load-bearing Part Of Mechanical Structure

Fatigue damage is the main failure mode of mechanical components. While the mechanical structure bears cycling load, fatigue and damage of mechanical structure may take place. The characteristics of structural fatigue damage can be analyzed by different fatigue analysis methods. In the actual operating conditions, load and working environment which the structure bearing is complicate, and the mechanical structure occurrence of fatigue has a lot of random. Therefore, the fatigue damage of mechanical structural will be effectively evaluated by the fatigue statistical analysis method from the view of mathematical statistics.In this dissertation, the fatigue state of mechanical structure is taken as the research object. According to the material characteristics and load-bearing conditions, the fatigue state of load-bearing part of mechanical structure is analyzed by using the method of mathematical statistics. Construct a small fatigue test device which is consistent with the material properties of structure. Four different experimental conditions are determined. The stress and strain of structure are analyzed by using the finite element method. The damage part of structure was determined under the action of load, which provides the accurate basis for arranging fiber Bragg grating.Based on the traditional fatigue analysis methods, fatigue influence factors of mechanical structure are analyzed, and the statistical analytical method of fatigue damage of mechanical structure is present. For the feature of structure bear load, and the change rules of stress and strain data were studied. The test data is processed by mean.According to the statistical analysis method of fatigue damage, the elastic modulus test data are analyzed by linear regression analysis. The results show that the fitting between test data of elastic modulus and the actual situation of structure is good. The test data of stability is analyzed by hypothesis test. While the fatigue of structure is take place, the test data of structure population mean is test significance. When the stress、strain and elastic modulus under the largest frequency and amplitude, the results show that the fatigue of structure is take place in a short time and the speed rate changes obviously. According to the statistical data analysis, the relationship between elastic modulus and fatigue damage are obtained. The fatigue time of structure and the influence of amplitude and frequency of load on the fatigue are determined. The fatigue state change rules of structure under different test conditions are summarized.The test data of stress、strain and elastic modulus of mechanical structure under different test conditions are analyzed in this dissertation. The relationship between elastic modulus and fatigue state is studied, and a statistical method is presented to evaluate the fatigue state of mechanical structure. All the research results can be theoretical and experimental basis for fatigue analysis of mechanical structure.