Method for calculating vibration fatigue life of large-length-diameter-ratio IV type gas cylinder BOSS structure

The invention discloses a method for calculating the vibration fatigue life of a BOSS structure of a large-length-diameter-ratio IV type gas cylinder, and relates to the technical field of gas cylinder vibration fatigue life test.A road surface random vibration load spectrum is obtained through actual measurement or based on related standards and data reports, and gas cylinder random vibration force response distribution under the action of random vibration loads is obtained through finite element analysis; and selecting a stress amplitude probability density function according to the modal stress, the random vibration stress and the displacement response of the gas cylinder in combination with the actually measured S-N fatigue life curve of the material, and calculating the random vibration fatigue life of the BOSS structure of the gas cylinder. According to the method, the characteristics of long span, low rigidity and large dead weight of the gas cylinder with the large length-diameter ratio are fully cons