Mixed uncertainty structure fatigue life analysis method based on chaotic polynomial expansion

A technology of fatigue life analysis and chaotic polynomials, applied in geometric CAD, computer-aided design, calculation, etc., can solve the problems of large number of required samples and long time consumption

Pending Publication Date: 2020-03-31
BEIHANG UNIV
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Problems solved by technology

[0006] The technical problem to be solved by the present invention is: to overcome the shortcomings of the existing uncertain structural fatigue life analysis methods that require a large number of samples and consume a long time, and provide a structural fatigue life prediction method that considers mixed uncertainties

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  • Mixed uncertainty structure fatigue life analysis method based on chaotic polynomial expansion
  • Mixed uncertainty structure fatigue life analysis method based on chaotic polynomial expansion
  • Mixed uncertainty structure fatigue life analysis method based on chaotic polynomial expansion

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Embodiment Construction

[0064] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0065] Such as Figure 7 As shown, the present invention proposes a method for analyzing the fatigue life of a mixed uncertainty structure based on chaotic polynomial expansion, including the following steps:

[0066] Step (1) to figure 1 The flat plate structure with a hole in the center shown is the analysis object, it bears the cyclic tension and compression load with the average stress of 0, the elastic modulus of the material is E=200GPa, and the Poisson’s ratio is an interval parameter v∈[0.20,0.40], according to The sample points generated by the LHS method are as follows:

[0067] ν (1) =0.20, ν (2) =0.25, ν (3) =0.30, ν (4) =0.35, ν (5) =0.40 (21)

[0068] Convert the above sample points into the following standard interval parameters:

[0069] n (1) =-1, η (2) =-0.5, η (3) =0, η (4) =0.5, η (5) =1 (22)

[0070] Step (2...

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Abstract

The invention discloses a mixed uncertainty structure fatigue life analysis method based on chaotic polynomial expansion. In the method, firstly, a structural fatigue life is expanded into a chaotic polynomial series form based on a Hermite polynomial, a random variable is contained in the Hermite polynomial, and an interval variable is contained in a polynomial coefficient; wherein the coefficient in the polynomial can be solved by using a sample method and a least square method, the sample point of the random variable is solved by using a sparse Clenshaw-Curtis point collocation method, andthe sample point of the interval variable is solved by using a Latin hypercube method. After the polynomial coefficient is determined, the response surface model of the structural fatigue life is constructed, and the mean value and variance of the structural fatigue life can be calculated on the basis. According to the method, under the condition that the precision of the calculation result is guaranteed, the number of samples required for analyzing the fatigue life of the hybrid uncertainty structure is reduced, the analysis efficiency is improved, and a new thought is provided for structuralfatigue reliability design.

Description

technical field [0001] The invention relates to the field of structural fatigue life prediction, in particular to a method for analyzing the fatigue life of a mixed uncertainty structure based on chaotic polynomial expansion. Background technique [0002] In actual engineering, structures are often subjected to constantly changing dynamic loads. Although the stress level of these dynamic loads is lower than the yield limit and strength limit of the structure, the structure will suffer fatigue damage under the repeated action of these dynamic loads. At the same time, most engineering structures inevitably have internal defects in the process of production, processing and manufacturing. Under the action of alternating dynamic loads, these defects will lead to stress concentration and crack initiation, and the cracks will gradually expand and lead to structural fracture and damage. Threats to structural security. For aircraft structures, such alternating loads are widely prese...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F30/17G06F119/04
Inventor 邱志平张泽晟王磊马铭夏海军姜南祝博
Owner BEIHANG UNIV
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