Reliability degree predication method for composite material based on fatigue life distribution

A composite material, fatigue life technology, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve the problems of unsuitable composite material test data dispersion, large calculation amount, unfavorable engineering operation, etc., and achieve technical characteristics Simple, physically meaningful, and easy-to-use effects

Inactive Publication Date: 2014-05-07
HOHAI UNIV
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Problems solved by technology

The first two methods mentioned above have a large amount of calculation, which is not conducive to actual engineering operations; the third method uses the probability density distribution of the Mittag-Leffler distribution, and the cumulative distribution functio

Method used

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  • Reliability degree predication method for composite material based on fatigue life distribution
  • Reliability degree predication method for composite material based on fatigue life distribution
  • Reliability degree predication method for composite material based on fatigue life distribution

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Embodiment 1

[0061] (1) The present invention takes the unidirectional carbon / epoxy composite material as an example for axial pull-pull loading on the AMSLER10HFP1-478 high-frequency fatigue machine produced in Switzerland, and the sample size of the fatigue life data is 50 (see: the data comes from Document 2 Xu Renping. Research on fatigue life data of composite materials [J]. Material Development and Application, 9,18-21,1994).

[0062] (2) See figure 2 As shown, the cumulative distribution function of the Mittag-Leffler distribution is used to simulate the cumulative distribution of fatigue life of unidirectional carbon / epoxy composites. First, the value of the scale parameter σ of the Mittag-Leffler distribution is determined by fractional moment estimation, and then the value of the stability index α is estimated by the least square method, as shown in Table 1.

[0063] Table 1 Stability index α and scale parameter σ corresponding to Mittag-Leffler distribution

[0064] ...

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Abstract

The invention discloses a reliability degree predication method for composite material based on fatigue life distribution. According to the method, firstly, the fatigue life distribution of the composite material is depicted through Mittag-Leffler distribution, then in combination with a corrected Miner equivalent damage principle, accumulated damaged statistics distribution of the composite material is determined, and finally by the adoption of a Monte Carlo method, fatigue reliability degrees of the composite material under the different numbers of load circulation times are predicated. Parameters of the Mittag-Leffler distribution are less than parameters of a frequently-used three-parameter Weibull distribution, and the physical significance of the parameters is clear; the improved Miner equivalent damage principle considers influences on the sequence of loads exerted on the composite material and is simple in technical characteristic and convenient to use for engineering technicians. The reliability degree predication method can be used for predicating the fatigue reliability degrees of the composite material, is a reference for drawing up a repairing plan of composite material components and has important theoretical and engineering significance.

Description

technical field [0001] The invention belongs to the field of fatigue reliability of composite materials, and in particular relates to a method for predicting reliability of composite materials based on fatigue life distribution. Background technique [0002] At present, composite materials have been widely used in aerospace, biomedicine, building materials, electronic equipment and other fields. Composite materials are brittle materials with highly dispersed mechanical properties. Statistical values ​​corresponding to a certain reliability index of materials are usually used in engineering design. Therefore, it is necessary to clarify the statistical laws of material properties. [0003] In the existing methods for predicting the reliability of composite materials, the cumulative damage is usually taken as a random variable, and the fatigue life distribution of composite materials is used to determine the random distribution of cumulative damage. A large number of experimen...

Claims

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Application Information

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IPC IPC(8): G06F17/50
Inventor 陈文梁英杰
Owner HOHAI UNIV
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