Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Fatigue life prediction method for friction stir welded component based on small crack propagation

A fatigue life prediction and friction stir welding technology, which is applied in special data processing applications, instruments, electrical digital data processing, etc., can solve the problems of different small crack propagation laws and difficult life prediction, and achieve the effect of simple calculation methods

Active Publication Date: 2018-11-30
BEIJING UNIV OF TECH
View PDF3 Cites 27 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the different material parameters such as microstructure and properties in each area of ​​the friction stir welded joint, the small cracks initiated in different areas of the joint are affected by the microstructure and properties, and the propagation laws of small cracks are different, so it is difficult to use a unified formula life prediction

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Fatigue life prediction method for friction stir welded component based on small crack propagation
  • Fatigue life prediction method for friction stir welded component based on small crack propagation
  • Fatigue life prediction method for friction stir welded component based on small crack propagation

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0086] Example 1: Fatigue Life Prediction of 7075 Aluminum Alloy Friction Stir Welded Joint Based on Small Crack Growth

[0087] (1) Prepare 7075 aluminum alloy friction stir welding fatigue samples, carry out fatigue small crack growth replica tests with different stress loading and stress ratios of 0.1 and -0.3 in different areas of the joint, and use the secant method to calculate the small crack growth rate; (2) Use the New-Raju model to calculate the range of stress intensity factors for small cracks in welded joints; (3) Measure the c value in the depth direction and the a / 2 value in the width direction of the semi-arc-shaped fatigue crack propagation zone in the fracture morphology of different regions of the welded joint , the calculated average value of the crack depth-length ratio 2c / a is about 0.9; (4) Draw the curves of crack growth rate changing with the range of stress intensity factor under different stress ratios and different stress levels, as shown in image ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a fatigue life prediction method for a friction stir welded component based on small crack propagation, and belongs to the technical field of fatigue diagnosis and analysis ofmechanical structures. The method comprises the steps that a bone-shaped flat plate sample is prepared, fatigue small crack propagation replica tests under different stress loads and different stressratios are conducted on different areas of a joint, and a secant method is adopted for calculating the propagation rate of small cracks; a New-Raju model is adopted for calculating the stress intensity factor range of the small cracks of the joint; c values in the depth direction and a / 2 values in the vertical direction of semi-arc shapes of fatigue crack propagation zones in fracture shapes of different areas of the joint, and the depth-to-length ratio 2c / a of the cracks is calculated; a curve of the propagation rate of the cracks along with the change of the stress intensity factor range isdrawn; an effective stress intensity factor is calculated; a formula of the propagation rate of the small cracks is determined; an initial crack size a0 and a critical crack size ac are determined; the formula of the propagation rate of the small cracks is integrated to obtain the fatigue life of the welded component. By means of the scheme, the fatigue life of the friction stir welded component can be more easily and accurately predicted.

Description

technical field [0001] The invention relates to a method for predicting fatigue life, in particular to a method for predicting fatigue life of a friction stir welded component based on small crack propagation, and belongs to the technical field of fatigue diagnosis and analysis of mechanical structures. Background technique [0002] For friction stir welded components, the welded joint is the weakest part of the entire structure, and the main failure mode of welded components is fatigue fracture. Fatigue specimens undergo the process of crack initiation, small crack growth and long crack growth. Among them, the initiation and propagation stages of small cracks account for about 70% to 80% of the fatigue life. In most cases, the sample is damaged due to initial microscopic defects such as inclusions, hardened particles, and micro-holes inherent in the material itself, or due to collisions, nicks, and corrosion during processing. For friction stir welded joints, the initiati...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F2119/04G06F30/20
Inventor 孙国芹王崇文魏心海
Owner BEIJING UNIV OF TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products