Inside Pressure Cylindrical Shell Opening Nozzles Reinforcing Structure By Area Replacement Method Safety Analysis Based On Ansys

Pressure vessel as the process equipment , to meet the requirements of process, structure, process control are needed to implement opening nozzles. Stress characteristics of the pressure vessels decided stress state of the opening nozzles area is complex, pressure vessel opening brings a disadvantageous over the stress distribution and strength.This article in accordance with the provisions of GB150-98, conducting all parts size calculation of shell, opening nozzles ,according to GB150-98 area replacement method of reinforcement effect calculation, using ANSYS to establish cylinder shell opening nozzles structure parameters process command to conduct strength analysis calculation, And according to the analyzed design standards of steel pressure vessel(JB4732), effecting reinforcing structure safety analysis.According to the stress Clounds chart, tests within the GB150-98 stipulated scope of no-reinforcement is safe. conditions beyond testing results show that to overpressure 3Mpa used and the diameter 95mm, reduce thickness (5mm) are safety, and the maximum stress value and stability boundary values are very large space, has certain safety margin.Facts have proved that the provisions GB150-98 no-reinforcement structure tends to keep conservative, in use may relax appropriately, but in use should be strict with stress analysis.Setting for the 1500mm diameter shell, opening diameter of over 508mm, to check safety of GB150-98 , Through analysis, the main reason of the structure failure is rigid of the opening nozzles and shell and reinforcement pad not to be coordinated, the fundamental reason is the design confined to equivalent strength theory caused the difference of metal cross-sectional area are excessive. The main avoiding measures in the design of is to make the wall thickness and shell thickness coordinated, which is equivalent to increase opening nozzles wall thickness and took over the thickness reinforcement pad, after the reinforcement the opening nozzles can reduce thickness of the of reinforcement pad,.The truth proves that thick-walled tube Structural reinforcement is better than reinforcement pad structure.The environment is not suitable for the reinforcement pad, such as heat, cold, alternating fatigue, stress corrosion, large opening nozzles structure, and other specific environment, the proposed priority in the design of reinforced structures using thick-walled tube.Rely solely on the reinforcement pad, when the opening size and operating pressure is large, the opening nozzles wall thickness is much smaller compared to Cylindrical shell wall,applied pressure load due to resulting in a larger deformation of the opening nozzles wall. shell wall thickness andhe opening nozzles wall thickness differences is over a large, result in poor coordination of structural deformation and form a bending stress, leading to excessive general stress, resulting in structural failure.Reinforcing the regional area of thick-walled opening nozzles is at the area of maximum stress, Can reduce stress concentration effectively.Rely solely on thick opening nozzles wall reinforced, when faced with large opening nozzles or high-pressure work environment, the need to provide the reinforcement area is large, the wall thickness of thick-walled tube can cause large, increasing the production of welding and other manufacturing difficulties.The deformation caused a new incompatible to opening nozzles and shell, creating a large bending moment. Thus, high pressure large diameter opening approach is to reduce the overall stress of the shell and opening nozzles the coordination of the wall thickness.When the operating pressure reaches 6.5Mpa, it is already beyond the technical regulations stipulated in the aforementioned reinforcement pad pressure to limit use, but the stress check results show that, as long as a reasonable structure design, avoid large bending deformation and bending stress ,n the work out regulations under the pressure of reinforcement pad structure is also available. For the specific environment, must be alculation for stress to prevent stress damage.