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CN-121997673-A - Aluminum alloy multiaxial fatigue life prediction method based on non-proportional loading effect

CN121997673ACN 121997673 ACN121997673 ACN 121997673ACN-121997673-A

Abstract

The embodiment of the application relates to the fields of mechanical engineering and material science, in particular to an aluminum alloy multiaxial fatigue life prediction method based on a non-proportional loading effect. The method comprises the steps of carrying out uniaxial tensile mechanical test processing on an aluminum alloy to generate stress strain data, determining a candidate plane set based on the stress strain data, determining a stress tensor and a strain tensor corresponding to each candidate plane in the candidate plane set based on the stress strain data to obtain a stress tensor set and a strain tensor set, determining a critical plane based on the stress tensor set, the strain tensor set and the candidate plane set, determining a damage parameter based on a damage model and the critical plane, and predicting the fatigue life of the multiaxial load based on the damage parameter and a Manson-Coffin equation. The embodiment can realize the accurate prediction of the fatigue life of the aluminum alloy cross beam of the vulcanizing machine.

Inventors

  • LIU XIAOANG
  • Kang Qizhe

Assignees

  • 河北工业大学

Dates

Publication Date
20260508
Application Date
20260225

Claims (10)

  1. 1. The aluminum alloy multiaxial fatigue life prediction method based on the non-proportional loading effect is characterized by comprising the following steps of: carrying out uniaxial tensile mechanical test treatment on the aluminum alloy to generate stress strain data; Determining a candidate plane set based on the stress-strain data; Based on the stress-strain data, determining a stress tensor and a strain tensor corresponding to each candidate plane in the candidate plane set, and obtaining a stress tensor set and a strain tensor set; Determining a critical plane based on the set of stress tensors, the set of strain tensors, and the set of candidate planes; determining damage parameters based on the damage model and the critical plane; and predicting the fatigue life of the multiaxial load based on the damage parameters and the Manson-Coffin equation.
  2. 2. The method for predicting multiaxial fatigue life of aluminum alloys based on non-proportional loading effect according to claim 1, wherein the stress tensor corresponding to each candidate plane in the set of candidate planes is: , Wherein, the The time is represented by the time period of the day, The stress tensor is represented by the number of stress tensors, 、 、 、 、 、 Normal and tangential stress components in the x, y and z coordinate directions are respectively represented; the strain tensor corresponding to each candidate plane in the set of candidate planes is: , Wherein, the The strain tensor is represented by a graph of the strain tensor, 、 、 、 、 、 The normal and tangential strain components in the x, y, z coordinate directions are shown, respectively.
  3. 3. The method for predicting multiaxial fatigue life of an aluminum alloy based on non-proportional loading effects of claim 1 wherein the critical plane comprises a shear strain range, a shear stress range, a normal strain range, and a normal stress range, wherein, The shear strain range is: , Wherein, the The number of the sequence is indicated, The number of the sequence is indicated, Indicates the serial number, and , A range of shear strain is indicated and, Represent the first The shear strain component in the xy direction of the step is analyzed, Represent the first The shear strain component in the xy direction of the step is analyzed, Represent the first The shear strain component in the step xz direction is analyzed, Represent the first The shear strain component in the step xz direction is analyzed, The shear stress range is: , Wherein, the Representing the number of sub-steps in each loading cycle, A range of shear stresses is indicated, Represent the first The shear stress component of the step is analyzed, Represent the first The shear stress component of the step is analyzed, The normal strain range is: , Wherein, the Representing the maximum positive strain range at the critical plane, Represent the first The normal strain component of the analyzing step is, Represent the first The normal strain component of the analyzing step is, The normal stress range is: , Wherein, the Represents the normal stress range, Represent the first The normal stress component of the analyzing step is, Represent the first The normal stress component of the step is analyzed.
  4. 4. The method for predicting multiaxial fatigue life of aluminum alloy based on non-proportional loading effect of claim 1 wherein the damage model is: , Wherein, the The parameters of the damage are indicated, Indicating the material constant(s) that are present, Representing the maximum positive stress on the critical plane, Indicating the yield strength of the material, Representing the maximum shear strain range in the critical plane.
  5. 5. The method for predicting multiaxial fatigue life of aluminum alloys based on non-proportional loading effects according to claim 4, wherein the material constants in the damage model are determined by fitting uniaxial and torsional fatigue data as shown in the following equation: , Wherein, the Represents the modulus of elasticity in shear fatigue strength, Represents the ductile coefficient of shear fatigue strength, Represents the young's modulus, Indicating the fatigue life of the article, The shear fatigue elasticity index is indicated as such, Represents the shear fatigue ductility index of the steel sheet, Representing the elastic poisson's ratio, Representing the poisson's ratio of plasticity, The tensile fatigue strength coefficient is indicated as the coefficient of tensile fatigue, Represents the young's modulus, The fatigue strength index is indicated as being indicative of the fatigue strength, The coefficient of fatigue ductility is indicated, Indicating the fatigue ductility index.
  6. 6. The method for predicting multiaxial fatigue life of aluminum alloy based on non-proportional loading effect according to claim 1, wherein predicting multiaxial load fatigue life based on the damage parameter and Manson-Coffin equation comprises: based on the damage parameters and the Manson-Coffin equation, predicting the fatigue life of the multiaxial load by the following formula: , Wherein, the Represents the modulus of elasticity in shear fatigue strength, Represents the ductile coefficient of shear fatigue strength, Represents the young's modulus, Indicating the fatigue life of the article, The shear fatigue elasticity index is indicated as such, And represents the shear fatigue ductility index.
  7. 7. The method for predicting multiaxial fatigue life of an aluminum alloy based on the non-proportional loading effect of claim 1, further comprising: performing fatigue life test treatment on the aluminum alloy under proportional and non-proportional multiaxial load conditions to generate experimental life; Based on the experimental lifetime and the fatigue lifetime, a prediction error is determined by the following formula: , Wherein, the The prediction error is represented by a prediction error, The experimental life is represented; The normal distribution error corresponding to the fatigue life is determined by the following formula: , Wherein, the Indicating that the error of the normal distribution is present, The standard deviation of the error is indicated, Represents the absolute error of the average value, , Representing the number of samples to be taken, Represent the first Prediction error of individual samples.
  8. 8. An aluminum alloy multiaxial fatigue life prediction device based on a non-proportional loading effect is characterized by comprising: The testing unit is configured to perform uniaxial tensile mechanical testing treatment on the aluminum alloy to generate stress strain data; A first determination unit configured to determine a candidate plane set based on the stress-strain data; A second determining unit configured to determine a stress tensor and a strain tensor corresponding to each candidate plane in the candidate plane sets based on the stress-strain data, resulting in a stress tensor set and a strain tensor set; A third determining unit configured to determine a critical plane based on the set of stress tensors, the set of strain tensors, and the set of candidate planes; A fourth determination unit configured to determine a damage parameter based on the damage model and the critical plane; And the prediction unit is configured to predict the fatigue life of the multiaxial load based on the damage parameter and a Manson-Coffin equation.
  9. 9. A computer device comprising a processor, a memory, and a computer program stored on the memory and executable by the processor, wherein the computer program when executed by the processor implements the steps of the method according to any of claims 1-7.
  10. 10. A computer readable storage medium, characterized in that the computer readable storage medium has stored thereon a computer program, wherein the computer program, when being executed by a processor, realizes the steps of the method according to any of claims 1-7.

Description

Aluminum alloy multiaxial fatigue life prediction method based on non-proportional loading effect Technical Field The embodiment of the application relates to the fields of mechanical engineering and material science, in particular to an aluminum alloy multiaxial fatigue life prediction method based on a non-proportional loading effect. Background In modern mechanical equipment and heavy industrial equipment, critical load bearing members are often in service in complex alternating load environments for long periods of time. Due to the existence of geometric discontinuities such as holes, chamfers, connection interfaces, etc., localized areas of the structure tend to exhibit significant multiaxial stress strain states. A large number of engineering failure cases indicate that multiaxial fatigue, particularly non-proportional multiaxial fatigue, is one of the main causes of premature failure of metallic structures. In the existing engineering, the multiaxial fatigue life prediction method mainly comprises an equivalent stress method, an equal effect transformation method, an energy method and a multiaxial fatigue model based on a critical plane method. The critical plane method is developed according to the observation of experimental phenomena of crack nucleation and expansion in the loading process, has good multiaxial fatigue life assessment capability and definite physical significance, and is widely applied. In order to improve the prediction accuracy under the non-proportional loading condition, various improved models based on a critical plane method, such as a SWT (stabilized wavelet transform) model, a FS (feature selection) model, a MSWT (multi-scale wavelet transform) model and the like, are proposed. The models introduce the influence of positive stress or shearing energy on fatigue damage to a certain extent, but the problems of more model parameters, high engineering calibration cost, insufficient prediction stability under specific materials and load paths and the like still exist. Particularly, for typical engineering materials such as 7050 series high-strength aluminum alloy and the like, under the action of complex non-proportional load, the model is still difficult to simultaneously consider prediction precision and engineering applicability. Therefore, it is necessary to develop a novel multi-axis fatigue life prediction method which can reasonably represent the additional hardening effect under the non-proportional loading condition, has clear model form and definite physical meaning of parameters, and is easy to popularize and apply in engineering. Disclosure of Invention The summary of the application is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. The summary of the application is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Some embodiments of the present application provide methods, apparatus, computer devices, and computer-readable storage media for predicting multi-axial fatigue life of aluminum alloys based on non-proportional loading effects, solving one or more of the technical problems mentioned in the background section above. In a first aspect, some embodiments of the application provide a method for predicting multiaxial fatigue life of an aluminum alloy based on a non-proportional loading effect, the method comprising performing uniaxial tensile mechanical test processing on the aluminum alloy to generate stress strain data, determining a candidate plane set based on the stress strain data, determining a stress tensor and a strain tensor corresponding to each candidate plane in the candidate plane set based on the stress strain data, obtaining a stress tensor set and a strain tensor set, determining a critical plane based on the stress tensor set, the strain tensor set and the candidate plane set, determining a damage parameter based on a damage model and the critical plane, and predicting fatigue life of multiaxial load based on the damage parameter and a Manson-Coffin equation. In a second aspect, some embodiments of the present application provide an aluminum alloy multiaxial fatigue life prediction apparatus based on a non-proportional loading effect, the apparatus including a test unit configured to perform uniaxial tensile mechanical test processing on an aluminum alloy to generate stress strain data, a first determination unit configured to determine a candidate plane set based on the stress strain data, a second determination unit configured to determine a stress tensor and a strain tensor corresponding to each candidate plane in the candidate plane set based on the stress strain data, to obtain a stress tensor set and a strain tensor set, a third determination unit configured to determine a critical plane based on the stress tensor set, the strain tensor set