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A creep buckling failure judgment criterion-based long-term service life prediction method for an organic glass pressure-bearing structure

A technology for plexiglass and service life, applied in computer-aided design, special data processing applications, instruments, etc., can solve problems such as inappropriate description of plexiglass creep behavior, incomplete creep buckling judgment criteria, etc., and achieve accurate prediction Effect

Inactive Publication Date: 2019-04-23
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] In view of the above deficiencies, the present invention provides a long-term service life prediction method for plexiglass pressure-bearing structures based on the creep buckling failure judgment criterion, which solves the inappropriate description of the creep behavior of plexiglass and the inappropriate creep buckling judgment criterion in the prior art. Comprehensive problem, this invention aims to consider the creep damage behavior of plexiglass under multiaxial stress state, and propose a creep buckling failure criterion, so as to more accurately predict the long-term service life of plexiglass thin-walled structures

Method used

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  • A creep buckling failure judgment criterion-based long-term service life prediction method for an organic glass pressure-bearing structure
  • A creep buckling failure judgment criterion-based long-term service life prediction method for an organic glass pressure-bearing structure
  • A creep buckling failure judgment criterion-based long-term service life prediction method for an organic glass pressure-bearing structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Example 1: Predict the long-term service life of a plexiglass spherical shell with an inner diameter of 10 m and a wall thickness of 34 mm.

[0051] Through the plexiglass uniaxial creep rupture experiment, the stress-strain curves under five stress levels (17.5MPa, 22MPa, 25MPa, 27.5MPa and 30MPa) were obtained; based on the results of the plexiglass creep experiment under uniaxial stress state, an organic The creep-damage constitutive equation of glass under multiaxial stress state, such as figure 2 Shown; The creep-damage constitutive equation under the described multiaxial stress state is the revised Liu-Murakami creep damage constitutive equation, as follows:

[0052]

[0053]

[0054] σ r =ασ I +(1-α)σ eq (3)

[0055] in, represents the creep strain rate, σ eq Indicates the von Mises equivalent stress, S ij represents the deviatoric stress, ω represents the creep damage variable, σ r represents the equivalent stress, σ I is the maximum principal st...

Embodiment 2

[0072] Example 2: Predict the minimum wall thickness of a plexiglass thin-walled spherical shell with an inner diameter of 10 m to meet the long-term service life of 20 years.

[0073] The finite element modeling method is the same as Example 1, the difference is that the spherical shell wall thickness t of the finite element model in Example 2 is selected from seven groups, which are 30mm, 34mm, 38mm, 40mm, 44mm, 48mm and 52mm.

[0074] Figure 5 It is the graph of the creep deformation at a certain point at the bottom of the plexiglass spherical shell with different wall thicknesses in Example 2 of the present invention. After the critical time, the creep deformation increases rapidly.

[0075] Image 6 It is the relationship diagram between the maximum stress and the corresponding long-term service life of plexiglass spherical shells with different wall thicknesses in Example 2 of the present invention. The long-term service life is obtained by the creep buckling failure ...

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Abstract

The invention discloses a creep buckling failure judgment criterion-based long-term service life prediction method for an organic glass pressure-bearing structure, which comprises the following stepsof obtaining stress-strain curve under different uniaxial stress levels through an organic glass uniaxial creep rupture experiment; based on the creep experiment result of the organic glass in the uniaxial stress state, carrying out the parameter fitting, obtaining the creep parameters in the multiaxial state, so that a creep-damage constitutive equation of the organic glass in the multiaxial stress state is established; based on the CREEP module of the finite element software ABAQUS, embedding the creep-damage constitutive equation into finite element analysis, judging whether the organic glass structure has creep buckling or not according to a creep buckling failure judgment criterion, and predicting the long-term service life of the structure. The invention aims to consider the creep damage behavior of the organic glass in a multi-axis stress state, and provides a creep buckling failure judgment criterion, thereby more accurately predicting the long-term service life of the organicglass thin-wall pressure-bearing structure.

Description

technical field [0001] The invention relates to the technical field of reliability engineering, in particular to a long-term service life prediction method of an organic glass pressure-bearing structure based on a creep buckling failure judgment criterion. Background technique [0002] Because of its good comprehensive mechanical properties and optical properties, plexiglass is widely used in the manufacture of pressure-bearing equipment, such as neutrino detectors [1] and so on. The neutrino detector is a thin-walled container that withstands external pressure. Due to detection requirements, the container is required to be able to operate stably for at least 20 years. [0003] For thin-walled structures subjected to external pressure, when the external pressure is greater than the buckling critical load, buckling deformation will occur and stability will be lost. In particular, plexiglass is a typical viscoelastic material, even at ambient temperature, creep and creep dama...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/23G06F2119/04G06F2119/06
Inventor 周凡蒋文春杜洋
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)