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A Method for Fatigue Crack Growth Rate Estimation and Life Prediction

A technology for fatigue crack growth and life prediction, applied in calculation, special data processing applications, instruments, etc., can solve problems such as complex models or methods, and achieve the effects of easy understanding and acceptance, reasonable and credible results, and convenient calculation

Inactive Publication Date: 2018-03-09
BEIHANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, it needs to be emphasized that compared with the Paris fatigue crack growth formula, these modified or developed models or methods are too complex and require designers to be familiar with precise fatigue fracture knowledge

Method used

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  • A Method for Fatigue Crack Growth Rate Estimation and Life Prediction
  • A Method for Fatigue Crack Growth Rate Estimation and Life Prediction
  • A Method for Fatigue Crack Growth Rate Estimation and Life Prediction

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Embodiment

[0111] In order to understand more fully the characteristics of the invention and its applicability to engineering practice, the present invention aims at such as Figure 2-4 The fatigue crack growth rate estimation and life prediction of the 2024-T3 aluminum alloy rectangular plate with unilateral cracks under uniform load are performed. The length of the aluminum alloy rectangular plate is S=120mm, and W=30mm. Breaking strength The shape factor F is 1.07, and the constant parameters C and m of the metal material are 3.868 and 0.377e-10, respectively. Nominal value of initial crack length a 0 is 5mm, the initial disturbance comes from the resolution of the measurement device.

[0112] The time-crack length (t-a) curve of fatigue crack growth can be obtained by using the Paris formula without considering the initial disturbance and the stress intensity factor obtained by the large-scale finite element general-purpose software ANSYS; among them, the large-scale finite eleme...

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Abstract

The invention discloses a method capable of carrying out fatigue crack propagation rate estimation and life prediction. The method comprises the following steps: (1) carrying out a fatigue crack test, and recoding data including crack length, time and the like; (2) processing the data to estimate a propagation rate corresponding to the crack length; (3) taking a Paris formula as a least-squares fit line to determine metal material parameters; (4) establishing a crack propagation perturbation series model to obtain a control equation and a boundary condition; (5) selecting a perturbation parameter asymptotic expansion control equation to form a perturbation parameter asymptotic sequence; (6) combining like terms to obtain differential equations under different powers to determine a coefficient to be determined, and carrying out iterative solving on the differential equations to obtain boundary conditions during next calculation; and (7) utilizing a calculation result to finish crack propagation rate estimation, judging whether the crack length exceeds a critical crack or not, jumping to (5) if the crack length exceeds the critical crack, and finishing fatigue life prediction if the crack length exceeds the critical crack. The method can effectively estimate the crack propagation rate and predict the fatigue life, and improves calculation precision.

Description

technical field [0001] The present invention relates to research on fatigue crack growth rate estimation and life prediction techniques, in particular to perturbation series characterization considering initial perturbation of crack length in fatigue crack growth model and crack growth rate estimation and life expectancy based on perturbation series method Prediction, in order to improve the calculation accuracy of crack growth rate estimation and life prediction, and ensure the correctness and validity of calculation results. Background technique [0002] Fatigue and fracture are the most common causes of component failure in engineering, and have attracted widespread attention in the fields of mechanics, aviation, and ships. Researchers in universities and research institutes mostly focus on the properties of cracked structures, including fatigue crack growth, residual strength and residual life. After fatigue cracks appear in the structure, its remaining life under alter...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/50
CPCG06F30/23
Inventor 邱志平陈潇王晓军王磊李云龙苏欢
Owner BEIHANG UNIV
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