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

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...

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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 function of the Mittag-Leffler distribution needs to be used to predict fatigue reliability; the fourth This method only uses the mean and standard deviation of turbine material test data, and is not suitable for describing the dispersion of composite material test data;

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