Welding fatigue analyzing method based on a rough set theory

Abstract

The invention discloses a welding fatigue analyzing method based on a rough set theory. The method comprises the following steps of S100, according to a plurality of sets of welded joint fatigue tests, establishing a fatigue database at least containing load attributes, maximum structural stress and number of cycle times; S200, calculating a structural stress change range delta (sigma s) for the maximum structural stress in the fatigue database; constructing attributes for the delta (sigma s) and the number of cycle times; generating decision attribute values in the rough set database, and writing into the rough set database; S300, using the welded joint basic parameters in the fatigue database as conditional attribute values in the rough set database, and writing into the rough set database; and S400, carrying out conditional attribute reduction and conditional attribute value reduction on the obtained rough set database containing the decision attribute values and the conditional attribute values by an united entropy reduction algorithm, so as to obtain a rough set decision rule model; and applying the rule model to analyze the welding fatigue data to obtain the rough set judging results, and then completing the fatigue welding analysis.

Description

technical field [0001] The invention relates to a welding fatigue analysis method, in particular to a welding fatigue analysis method based on rough set theory. G01N refers to the testing or analysis of materials by means of determining their chemical or physical properties. Background technique [0002] Welding is an important advanced manufacturing technology that plays a very important role in industrial production and national economic construction. The welded structure has the technical advantages of high strength, good sealing, high flexibility of structural design, simple process, easy repair, etc., and has been widely used in the manufacture of metal structures in many industrial sectors. The characteristics of the welding process and the geometric discontinuity of the joint make its fatigue strength far lower than that of the base metal. The existing research results show that the failure of the welded structure caused by fatigue damage is the most important way of...

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Problems solved by technology

[0008] In the main S-N curve method, the mesh-insensitive structural stress calculation solves the inconsistency in the finite element calculation of the weld stress distribution, but in the fatigue life evaluation stage based on the crack growth theory, the load form is simplified, and the material properties, The influence of welding process and other factors on fatigue life is ignored, and the above problems will reduce the accuracy of analysis and prediction of fatigue life of welded structures

The fatigue life of welded structures is affected by the coupling of various factors. The current welding fatigue analysis method is relatively independent in the analysis of the above-mentioned influencing factors, lacks the degree of correlation between them, and fails to comprehensively consider the influence of various factors.

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