Analysis Of The Stress Response And Fatigue Life Of The Typical Structure Under The Super-gaussian Vibration Excitation

Vibration is one of the most important environmental factors which affecting thereliability of equipments. The random vibration environment of equipments used to beseem as a smooth Gaussian distribution approximately in traditional view, but a lot ofvibration accelerated excitation caused by outfield applied environment ortransportation of equipments often show a clear super-Gaussian distributioncharacteristic. It is that the stress response not the accelerated excitation which damagethe equipments directly, so analyzing the stress response and fatigue life of the typicalstructure under the super-Gaussian vibration excitation is not only good for revealingthe mechanism of failure of equipments under the super-Gaussian vibration excitation,but also have significance of exploring the application of the super-Gaussian inaccelerated reliability test and evaluation.The main works and conclusions in this paper are as follows:1, The acceleration response signal of the typical cantilever structure under thesuper-Gaussian vibration excitation is converted to the displacement response signal tosolving the stress response, the applicability of the time and frequency integrationmethods in super-Gaussian vibration acceleration signals processing are analyzed andcompared, and then comparing the displacement signals respectively obtained by twointegration methods with the measured displacement signals by qualitative andquantitative analysis. The results show that the frequency domain integration methodhas better precision.2, Through theoretical derivation, the natural frequency of the structure of typicalcantilever and the analytical relationship between the displacement response and thestress response of the structural are obtained. A solving method from acceleratio nresponse to stress response can be obtained combined with the integral method above.3, The nominal stress method in the time domain method is applied to analyze thefatigue life of the typical cantilever structure. After having the time histories of thestress response of the structure, count it applying rainflow method, and estimate thefatigue life of the structure based on the performance curve of material fatigue andfatigue cumulative damage theory.4, Through the Gaussian/super-Gaussian vibration comparison testing, verify thecorrectness of analysis methods of the stress response and fatigue life of the structural,and reveal the accelerating effect of the substantial value of loading cycles of thesuper-Gaussian random stress to the process of fatigue cumulative damage of thestructural.