Embedded type finite element model tri-D crack enlargement emulation method

A crack propagation and simulation method technology, applied in the field of structural damage tolerance analysis, can solve problems such as poor automation, high modeling difficulty, and lack of versatility, and achieve high automation, good versatility, and low modeling difficulty Effect

Inactive Publication Date: 2007-10-24
NORTHWESTERN POLYTECHNICAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the disadvantages of high modeling difficulty, poor automation, and lack of versatility in the prior art, the present invention provides a three-dimensional crack propagation simulation method based on embedded finite element modeling, which can automatically divide the cracked structure multiple times, It has strong versatility for general three-dimensional cracked structures and improves the efficiency of crack growth analysis

Method used

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  • Embedded type finite element model tri-D crack enlargement emulation method
  • Embedded type finite element model tri-D crack enlargement emulation method
  • Embedded type finite element model tri-D crack enlargement emulation method

Examples

Experimental program
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Effect test

Embodiment 1

[0036] Method Example 1: Simulation of crack propagation behavior on the surface of a flat plate.

[0037] It is difficult to measure the three-dimensional crack growth test trajectory of the component, and the three-dimensional crack growth trajectory test data is rarely reported. This example is one of the few examples where the crack growth test data can be found, so as to verify the effectiveness of the patented method.

[0038] With the present invention, the main steps of crack propagation analysis of a flat plate with initial cracks on the surface are as follows:

[0039] 1) Read in the structural solid model-hexahedron;

[0040] 2) Read in the coordinates of the structural crack front point series-the coordinates of several points on the semi-elliptic curve;

[0041] 3) Form the embedded cracked body as shown in Figure 1b and the non-cracked body as shown in Figure 1c;

[0042] 4) Carry out finite element meshing. The cracked body meshing is shown in Figures 3 and 5, and t...

Embodiment 2

[0048] Method Example 2: A simulation of the crack propagation behavior of the tongue and groove corner of a fan disk.

[0049] In the above example, the crack surface is in the symmetry plane of the structure, and the modeling is relatively easy, and the advantages of the present invention are not yet fully reflected. The structure near the crack surface in this embodiment has no symmetry, which can reflect the adaptability of the present invention to the asymmetric crack structure. Under the action of centrifugal force and blade tension, surface cracks or corner cracks are often induced in the tongue and groove of the fan disc.

[0050] Using the present invention, the main steps of the crack propagation analysis of the corner cracks at the exhaust end of the tongue and groove of a compressor disk are as follows:

[0051] 1) Read in the solid model of the structure-the solid model of the outer contour of the compressor;

[0052] 2) Read in the coordinates of the front point sequ...

Embodiment 3

[0060] Method Example 3: An example of the expansion behavior of embedded inclusions in the subsurface of a semi-infinite body.

[0061] The above two cases are surface crack problems. When the crack is on the subsurface of the object, the crack propagation process is affected by the interference of the object boundary, which makes the numerical simulation encounter new difficulties. Powdered superalloy has excellent characteristics and is considered to be the material of choice for aero-engine discs. Since inclusions or voids are inevitable during the preparation process, especially the existence of sub-surface inclusions, it will seriously affect the fatigue characteristics of the roulette. This example presents a process of subsurface crack propagation and evolution into surface cracks to illustrate the ability of the present invention to simulate such problems. Semi-infinite body subjected to uniform tensile or bending loads, with an initial radius a 0 The subsurface circular ...

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Abstract

The invention discloses a three-dimension crack expanded simulate method, based on embedded finite element modeling, which shows the non-continuity of structure based on structure solid model, while the crack expansion is realized by changing crack shape and position of solid continuously. The invention first builds a n embedded crack sub model of upper and lower crack surfaces, divides the whole crack structure into a non-crack body and a crack body, wherein, the crack body is composed of upper and lower six solid sub blocks, the crack surface is between the upper and lower faces of four sub blocks as the third, fourth, fifth and sixth, that the crack surface is contained in the crack body and the crack body is embedded in the non-crack body. The invention can avoid digit error in the crack expansion process, caused by unreasonably divided unit, to support the description of cut or hole-crack in projection.

Description

Technical field [0001] The invention relates to a structural damage tolerance analysis method. Background technique [0002] The design concept of structural damage tolerance can be simply described as follows: According to the known structure with a certain size of initial flaws or cracks, under a given load spectrum, how long the structure can work safely, determine the appropriate maintenance period to To ensure the safe operation of the structure, at the same time, it can make full use of the difference in crack initiation life of different structures to maximize the potential of the structure. In order to numerically analyze the damage tolerance capability of the structure, it is necessary to model and analyze the structure containing three-dimensional cracks several times, simulate the crack propagation process and trajectory, and determine the critical state of rapid growth of the crack according to the fracture toughness of the material-the cracked structure It can work s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/00G06F17/00
Inventor 陆山唐俊星
Owner NORTHWESTERN POLYTECHNICAL UNIV
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