METHOD FOR CALCULATION AND SIMULATION ON PROPAGATION OF SURFACE CRACK ON SPHERICAL VESSELS MADE OF STEELS

To avoid leaking or bursing by crack on surface of preddure vessels made of streels,a method for analyzing the principle of propagation of a surface crack is established,and used on a spherical vessel with program calculation and simulation,the program is written in QBASIC and the reaults are provided and discussed.

FEM Simulation of the Hydroforming Process of Spherical Vessels from Combination Frustum Shells

The dieless hydroforming of spherical vessels from combination frustum shells is put forward in the present paper,and the forming process is developed by means of elastoplastic finite element method and experiments.In this paper the principle and experimental procedure of the new technology are introduced,the simulation method and the calculating assumptions are presented,the deformation process and the deformation characteristics of the shells are discussed,as well as the stress and strain distributions of the shell during bulging are analysed.

Research into tritium and helium-3 contents distributions in steel wall of spherical pressure vessel

The tritium quantity stored in a steel pressure vessel decreases with time because of helium-3 decay and permeation of tritium into the steel wall of the pressure vessel.Meanwhile,the tritium quantity permeating into the steel wall also decreases with time due to helium-3 decay and diffusion in and out of the wall of tritium.Tritium and helium-3 in the steel wall will cause hydrogen and helium embrittlement of the wall material,respectively,and thereby change the carrying capacity of the vessel.Taking contemporarily both decay and permeation of tritium within the vessel and decay and diffusion of tritium having permeated into the wall into consideration,the governing equations of tritium and helium-3 contents in the wall were established and solved,and relevant formulas were deduced.Through analytical calculations,curves of tritium and helium-3 contents versus radius and time were theoretically plotted,the contents spatio-temporal distributions laws were obtained,and a law about helium-3 contents distribution in steel wall of a spherical pressure vessel was discovered which was called the law of double helium-3 content.

Research on thermoforming process of JUNO large acrylic spherical panel

Introduction Jiangmen Underground Neutrino Observation(JUNO)focuses on determining neutrino mass hierarchy and other physical purposes.The central detector is one of the keys to the JUNO.The main structure of the central detector is an acrylic spherical container with a diameter of 35.4 m,which will be the largest acrylic spherical vessel in the world.Its construction will inevitably face many great challenges and difficulties.Method The thermoforming process of large acrylic spherical panel is introduced,which is a very important step in panel production.The effect of temperature on the curvature of panel during thermoforming is discussed.The thermal deformation of panel in thermoforming process is analyzed by finite element method.The bending experiment and curvature measurement are carried out,and the influence of deformation of the panel under gravity on the curvature of the panel is analyzed.Results The current thermoforming process makes the curvature of panel smaller than that of mold.The measurement results show that the curvatures are different due to the influence of gravity when the panel is placed on the mold or vertically.Some suggestions for improving the shape of spherical panels are put forward.In the thermoforming process,the temperature of the concave-convex surfaces of the panel should be controlled at the same level as far as possible.Another feasible method is to increase the radius of the forming mold to obtain a spherical panel with designed radius.