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Fatigue life analyzing method based on Paris formula

A technology of fatigue life analysis and formulas, applied in special data processing applications, instruments, electrical digital data processing, etc.

Inactive Publication Date: 2011-07-20
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] In order to overcome the complexity of existing technologies in engineering applications and the need to measure a large number of material constants, the present invention proposes a full-life analysis method based on crack growth data and fatigue life curves with stress ratio R=0, which can be used With the existing material constants, the structural fatigue life analysis of structures under constant amplitude load and random load spectrum reduces the cost and time of material constant testing, and provides a feasible method for fatigue life analysis of actual structures

Method used

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  • Fatigue life analyzing method based on Paris formula
  • Fatigue life analyzing method based on Paris formula
  • Fatigue life analyzing method based on Paris formula

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Embodiment Construction

[0055] Method implementation case: take the fatigue life calculation of flat standard fatigue specimen as an example to carry out the whole life calculation.

[0056] The analysis selects the material LY12CZ aluminum alloy thin plate smooth sample to carry out the whole life analysis, the sample is as follows figure 1 As shown, the dimension unit is mm, the thickness is t=2.5mm, and w=15mm.

[0057] Step 1: Refer to the "Handbook of Mechanical Properties of Metal Materials for Aircraft Structures" to obtain the static data of the structure, as shown in Table 1;

[0058] Step 2: Consult the "Handbook of Mechanical Properties of Metal Materials for Aircraft Structures" to obtain the Paris crack growth constant and SN curve data with R=0, the data are shown in Table 2;

[0059] Table 1 Static parameters of LY12CZ material

[0060]

[0061] Table 2 Fatigue and fracture parameters of LY12CZ material

[0062]

[0063] Step 3: Refer to the "Stress Intensity Factor Handbook" to...

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Abstract

The invention discloses a fatigue life analyzing method based on a Paris formula, comprising the following steps of: acquiring the mechanical property data and a fatigue SN (Serial Number) curve of materials as well as the Paris material constants of the materials when stress ratio R=0 and a stress intensity factor curve of a suture, and then calculating the influence factors of a crack length; and carrying out crack propagation life integral calculation from an initial crack length to a critical crack length by adopting a fatigue life-cycle calculation formula based on the Paris so as to obtain and output a final structure fatigue life-cycle. In the invention, only the basic common material constants are needed, therefore, the test measurement of a large quantity of material constants is prevented; and the prevention of the test measurement of the large quantity of material constants is very important for the structure life-cycle analysis of engineering application.

Description

technical field [0001] The invention relates to a method for analyzing the whole life of structural fatigue. Background technique [0002] Mechanical mechanisms are usually subjected to alternating loads during use, and fatigue damage is a major form of structural damage. In the fatigue life analysis, the fatigue cumulative damage theory is usually used for the prediction of the crack formation life, and the fracture mechanics theory is used for the prediction of the crack growth life. Since the life given by these two theories cannot be well connected, it is not convenient to analyze the fatigue life of the component, and the fatigue damage of the material itself is a process of continuous change, so a unified theory is used to calculate the fatigue life distribution of the structure It is feasible, and some progress has been made in applying the theory of fracture mechanics to fatigue life analysis and establishing a life calculation model suitable for the whole process o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F19/00
Inventor 殷之平谢伟黄其青傅祥炯
Owner NORTHWESTERN POLYTECHNICAL UNIV
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