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A Particle Filter Algorithm Based Crack Fracture Prediction Method for NdFeB Magnets

A particle filter algorithm, particle filter technology, applied in the direction of prediction, calculation, manufacturing computing systems, etc., can solve the problems of low fracture toughness, low accuracy of prediction results, and inability to describe the formation process of short cracks well, and achieve application The effect of wide range and stable signal source

Active Publication Date: 2022-05-17
NANCHANG HANGKONG UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the particularity of the NdFeB magnet material, which has low fracture toughness, the use of damage mechanics methods cannot describe the formation process of short cracks in the initial stage of NdFeB magnet crack growth, resulting in the prediction results during the crack growth process. less accurate
[0005] Moreover, model-based simulation methods often need to pre-determine some test conditions. For example, the commonly used fatigue crack growth prediction based on the Paris formula, the calculation of the stress field intensity factor amplitude △k parameter is usually through numerical analysis and numerical simulation. Through this Although the prediction results obtained by this method take into account the basic laws of crack growth to a certain extent, they are still based on theoretical or empirical historical experimental data, and the variable parameters are very conservative, which cannot take into account the parameters of NdFeB materials. , the tortuosity change of the actual crack growth path and other uncertain factors
These factors all limit the accuracy and effectiveness of crack propagation fracture prediction
Traditional research methods and model simulations have been unable to accurately predict the evolution process of crack propagation and fracture of NdFeB magnets

Method used

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  • A Particle Filter Algorithm Based Crack Fracture Prediction Method for NdFeB Magnets
  • A Particle Filter Algorithm Based Crack Fracture Prediction Method for NdFeB Magnets
  • A Particle Filter Algorithm Based Crack Fracture Prediction Method for NdFeB Magnets

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Experimental program
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Effect test

Embodiment 1

[0065] In the geomagnetic field environment, a certain degree of external stress will cause the magnetization tendency of the component, resulting in lattice distortion of the material, and the magnetic energy change E caused by the change of the atomic magnetic moment in the step S4 σ Expressed as:

[0066]

[0067] where σ is expressed as stress, θ 1 , θ 2 , θ 3 Respectively represent the angle between the magnetization direction and the crystal axis, λ [100] , lambda [111] Indicates the magnetostriction coefficient of different crystal phases of the material, assuming that the magnetostriction of the material is isotropic, then there is λ [100] =λ [111] =λ σ , then formula (1) can be simplified as:

[0068]

[0069] In the formula, λ σ is the magnetostriction coefficient of the material under the action of stress σ, and θ is the angle between the stress direction and the magnetization direction. In the fatigue test, θ=0, the formula (2) is further simplified a...

Embodiment 2

[0075] The magnetostriction coefficient λ under the action of the elastic stage stress σ in the step S4 σ Expressed as:

[0076]

[0077] Among them, λ m is the saturation magnetostriction coefficient, B m is the saturation magnetic induction, and the values ​​of both are related to the properties of the material.

Embodiment 3

[0079] The relative permeability μ in the step S4 σ The obtaining steps are:

[0080] Bring formula (5) into formula (4), and simplify:

[0081]

[0082] Among them, μ is the initial relative magnetic permeability of the material when no external force is applied, λ m is the saturation magnetostriction coefficient, B m is the saturation magnetic induction intensity, both of which are related to the properties of the material. The stress-permeability model is improved by adding the state equation noise λ and ψ to eliminate the influence of uncertain factors such as local load changes and internal discontinuities of the material. :

[0083]

[0084] Among them, λ represents the effect of relative permeability change caused by internal factors of the material when external stress is applied (such as the discontinuity of the internal structure of the material), ψ represents the uncertainty effect caused by the local load change caused by crack initiation, and Δk represent...

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Abstract

The invention discloses a method for predicting cracks and fractures of NdFeB magnets based on a particle filter algorithm, and relates to the technical field of fatigue cracks and fracture predictions of metal materials. The magnetic induction intensity vector of NdFeB magnets is introduced into a particle filter prediction model and used as The state parameters in the constructed particle filter model are used to continuously monitor the crack growth information of NdFeB magnets. The magnetic signal state vector proposed by it can not only accurately predict the state change of the magnet when the crack expands, but also monitor the fluctuation of the magnetic induction intensity signal of the magnet with the fatigue load applied by the outside when the magnet is not broken.

Description

technical field [0001] The invention relates to the technical field of metal material fatigue crack fracture prediction, in particular to a particle filter algorithm-based NdFeB magnet crack fracture prediction method. Background technique [0002] As one of the most common forms of damage in workpieces, fatigue cracks will adversely affect the performance of workpieces. As an important metal functional material, NdFeB permanent magnet material has a series of advantages such as high magnetic energy product, high remanence and high coercive force. With its excellent magnetic properties and excellent function conversion, it is widely used in fans, motors and It is widely used in the manufacture of core functional devices in high-tech industries such as the new energy industry. However, the sintering process commonly used today makes the prepared NdFeB magnet prone to uneven density and porosity in the internal structure of the cooling process. At the same time, the local tem...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F30/25G06F30/17G06Q10/04G06Q50/04G06F111/10G06F119/04G06F119/14
CPCG06F30/25G06F30/17G06Q10/04G06Q50/04G06F2119/04G06F2119/14G06F2111/10Y02P90/30
Inventor 程东方严毅琪殷金泉邓强程强强于润桥孙鹏宇黄伟荣王勇博刘扬
Owner NANCHANG HANGKONG UNIVERSITY
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