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The conventional design method uses elastic failure as a criterion and film stress as a basis to calculate the thickness of the component. The maximum stress is limited to not exceed a certain allowable value (usually 1 times the allowable stress). Local stresses such as high edge stresses present in the container are represented in the form of stress enhancement factors, and the maximum stress after taking these local stresses into account is assigned the same allowable stress value as that for film stresses. The thicknesses of pressure vessels and spherical shells specified in GB/T150 are calculated based on the membrane stress within the components (the primary overall membrane stress), with this stress being kept at 1 time the allowable stress level. For the thickness of elliptical and butterfly heads, the local stress resulting from the edge effects between the head and the cylinder is taken into account, and the maximum stress obtained by combining this with the membrane stress is controlled to be within 1 time the allowable stress. The conventional design method is simple, but it is not entirely rational and tends to be conservative. The analytical design method is based on plastic and elastoplastic failure criteria; it takes into account various stresses within the container, such as overall membrane stress, edge stress, and peak stress, to carry out accurate calculations. The stresses are classified, and different strength constraints are applied according to the various types of failure caused by each type of stress, thereby enabling the calculation of the thickness of the components. Containers designed according to this method are more scientific, reasonable, safe, and reliable, and can also bring certain economic benefits. The thickness calculation for various components in the JB4732 standard is based on stress analysis and employs the third strength theory. Although the formula forms for calculating internal-pressure cylinders and spherical shells are the same as those in GB/T150, their computational purposes are entirely different. Analytical design, by distinguishing between different types of stresses and loads, fully utilizes the load-bearing capacity of materials; as a result, it imposes higher technical requirements on materials as well as on manufacturing and testing processes.