Strength evaluation method for tangential inclined connecting pipe under pipeline load effect

Abstract

The invention discloses a strength evaluation method for a tangential inclined connecting pipe under a pipeline load effect, and belongs to the technical field of pipeline load strength evaluation methods. The method comprises the steps: establishing a three-dimensional solid model of a tangential oblique connection pipe structure in a DM module of the ANSYS Workbench simulation platform; selecting a Solid186 secondary unit in the Meshing module to divide grids; adopting an ideal elastic-plastic material constitutive relation, a small-deformation theory and equal-proportion loading in a Stretch module to carry out limit load analysis on the tangential oblique connecting pipe structure under the design condition; carrying out the elastic stress analysis under the design condition on the tangential oblique connecting pipe structure in the Stretch module by adopting a linear elastic material constitutive relation and a small deformation theory, and carrying out the evaluation for preventing local failure on a key part on the basis of the sum of three-way principal stress of a thin film and bending; in the Stretch module, adopting a linear elastic material constitutive relation and a small deformation theory to carry out elastic stress analysis on a tangential oblique connecting pipe structure under an operation condition, and extracting primary and secondary stress of a stress classification line from a key part to evaluate ratchet wheel failure prevention.

Description

technical field [0001] The invention relates to a method for evaluating the strength of a tangentially mitered pipe under the action of pipeline load, and belongs to the technical field of pipeline load strength assessment methods. Background technique [0002] Tangentially mitered pipes under the action of pipeline loads widely exist in pressure vessel equipment, and its strength check is beyond the scope of use of the general process equipment design software SW6. At this time, the finite element method is generally used in the industry for detailed stress analysis , and evaluated according to the stress classification method of JB4732-1995 "Steel Pressure Vessels-Analysis and Design Standard". However, the bending stress at the root of the nozzle calculated by the finite element software includes primary stress and secondary stress components, which are difficult to distinguish. At present, the common practice in the industry is to divide the bending stress into primary ...

AI Technical Summary

Problems solved by technology

However, the bending stress at the root of the nozzle calculated by the finite element software includes primary stress and secondary stress components, which are difficult to distinguish

At present, the common practice in the industry is to divide the bending stress into primary stress, and use 1.5 times the allowable stress to control the bending stress of the film at the root of the connection tube, which leads to an overly conservative design and is very uneconomical.

Another method is to only evaluate the primary stress plus secondary stress, and use 3.0 times the allowable stress to control the film plus bending stress at the root of the connecting pipe. These methods do not take into account the influence of the primary bending stress, which may lead to unsafe situations

Images