Designing method for realizing equal load-carrying of tension-loaded butt joint with central crack on welding line, and application of K factor

A technology for butt joints and central cracks, which is applied in special data processing applications, calculations, instruments, etc., and can solve problems such as low-stress brittle fracture accidents and low bearing capacity of joints

Inactive Publication Date: 2011-07-27
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to provide a design method and the application of K factor for realizing equal load bearing of butt joints with central cracks in welds and tensile loads, so as to solve the problem that the bearing capacity of butt joints with central cracks in welds is lower than that of parent joints. material bearing capacity, and the joint is prone to the problem of low stress brittle fracture; the present invention also proposes the stress i

Method used

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  • Designing method for realizing equal load-carrying of tension-loaded butt joint with central crack on welding line, and application of K factor
  • Designing method for realizing equal load-carrying of tension-loaded butt joint with central crack on welding line, and application of K factor
  • Designing method for realizing equal load-carrying of tension-loaded butt joint with central crack on welding line, and application of K factor

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Example Embodiment

[0090] Specific embodiment one: see figure 1 The design method for butt joints with central cracks in welds that are subject to tensile load to achieve equal load-bearing in this embodiment is based on the ratio of the stress intensity factor of the weld and the base metal and the fracture toughness of the weld and the base metal. The ratio is equal, and the stress concentration coefficient of the weld toe is reduced as much as possible to achieve equal load; according to the characteristics of the load, in order to ensure the fatigue strength of the butt joint, the weld shape of the butt joint is determined as figure 1 A simple arc curve transition weld shape is adopted between the reinforcement and the base metal shown; the design method of the butt joint is:

[0091] Step 1. Determine the equal load-bearing conditions when there are cracks in the weld zone and the base metal:

[0092] K I w K I b = K IC w K IC b - - - ( 1 ) ...

Example Embodiment

[0110] Specific implementation manner two: see figure 2 In this embodiment, the design method for butt joints with central cracks in welds subjected to tensile load to achieve equal load-bearing is based on the fact that the critical stress of crack instability propagation in the weld is equal to the tensile strength of the base material, and the weld toe stress is minimized. Concentration factor to achieve equal load bearing; according to the bearing characteristics, in order to ensure the fatigue strength of the butt joint, the weld shape of the butt joint is determined as figure 2 The shown weld shape between the reinforcement and the base metal adopts a simple arc curve transition; the design method of the butt joint is:

[0111] Step 1. Determine that the equal load-bearing conditions when there is a crack in the weld zone and the base material is free of defects:

[0112] σ c w = σ b b - - - ( 6 )

[0113] Where σ c w Is the critical stress...

Example Embodiment

[0131] Specific implementation manner three: see figure 1 In the method described in this embodiment, the cracks on the base metal are located at any position outside the total width of the cover weld. Other components and connection relationships are the same as those in the first embodiment.

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Abstract

The invention discloses a designing method for realizing the equal load-carrying of a tension-loaded butt joint with a central crack on a welding line, and the application of a K factor, which belong to the field of welding and aim to solve the problem that the load-carrying capacity of the tension-loaded butt joint with the central crack is lower than that of a parent metal. If the parent metal of the tension-loaded joint with the central crack on the welding line also has a crack, the designing method comprises the following steps of: determining equal load-carrying conditions, and the fracture toughness of a weld metal and the parent metal; calculating a stress intensity factor of a parent metal area and the stress intensity factor of a welding line area meeting equal load-carrying; calculating a stress intensity factor formula; and obtaining geometrical parameter values of the welding line. If the parent metal of the tension-loaded joint with the central crack on the welding line is free from defect, the designing method comprises the following steps of: determining the equal load-carrying conditions, and the tensile strength of the parent metal; calculating the stress intensity factor formula; determining a critical stress relational expression, and the fracture toughness of the weld metal; and obtaining the geometrical parameter values of the welding line. The stress intensity factor of the welding line area is applied to the calculation of critical crack size, critical stress and remaining service life of the tension-loaded joint with the central crack. The method and the application are applied to plate butt joints welded on both sides.

Description

technical field [0001] The present invention relates to a design method of a butt joint subjected to tensile load and the application of K factor, in particular to a design method of butt joint which can make a butt joint with a central crack in the weld be subjected to tensile load according to the bearing capacity of the parent material and The invention relates to an application method of a stress intensity factor in a weld zone, belonging to the technical field of welding. Background technique [0002] As a special connection method, welded structures are widely used in civil and military production design, etc., especially for the current lightweight requirements, high-strength materials are widely used. For welded joints, due to the role of the welding process, the properties of the material have changed greatly, and the conventional mechanical properties and fracture toughness of the joint local area have been greatly reduced. Welding defects are inevitable, especial...

Claims

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Application Information

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IPC IPC(8): G06F17/50
Inventor 杨建国王涛方洪渊刘雪松董志波方坤马子齐
Owner HARBIN INST OF TECH
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