CN112347574A - Elastoplasticity damage failure prediction method for additive manufacturing metal material - Google Patents

Elastoplasticity damage failure prediction method for additive manufacturing metal material Download PDF

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CN112347574A
CN112347574A CN202011176362.8A CN202011176362A CN112347574A CN 112347574 A CN112347574 A CN 112347574A CN 202011176362 A CN202011176362 A CN 202011176362A CN 112347574 A CN112347574 A CN 112347574A
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张凯
刘建林
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China University of Petroleum East China
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Abstract

The invention discloses an elastoplasticity damage failure prediction method for an additive manufacturing metal material. According to the method, an elastic-plastic model considering anisotropy and asymmetric hardening is established, and is strongly coupled with a ductile damage behavior on the basis, so that the damage failure of the additive manufacturing metal material under different loading paths is predicted, an effective method for evaluating the mechanical properties of the additive manufacturing metal material and the component thereof is explored, and theoretical guidance and a basis for optimizing the machining process are provided for the product performance evaluation of the additive manufacturing parts. Respectively researching the complex mechanical behavior of the metal material manufactured by the additive, and further researching the relation between the complex plastic behavior and damage failure; the model realizes numerical calculation by compiling a VUMAT subprogram method, and simultaneously gives a specific scheme of parameter calibration; and predicting the occurrence of elastoplasticity behaviors and damage failure under different loading paths based on the calibrated parameters. The method disclosed by the invention is used for carrying out numerical simulation and damage failure prediction on the metal material manufactured by the additive manufacturing based on the fully-coupled elastoplasticity damage model, is a reliable and efficient calculation model and method, and has important scientific innovativeness and engineering application value in the establishment of a relevant model.

Description

Elastoplasticity damage failure prediction method for additive manufacturing metal material
Technical Field
The invention relates to the field of metal material processing, in particular to an elastoplasticity damage failure prediction method for an additive manufacturing metal material.
Background
Additive manufacturing is a novel manufacturing technology for rapid free forming of three-dimensional entities. Compared with the traditional manufacturing method, the additive manufacturing technology increases the degree of freedom of design, and can manufacture parts with complex geometric configurations and excellent performance, so that the additive manufacturing technology has a great amount of application in the industries of aerospace, mechanical manufacturing and the like. Due to the particularity of the manufacturing process of the metal parts manufactured by the additive manufacturing and the complexity of the service working conditions, damage, fracture and failure are easily caused in engineering application. At present, a reliable model and a reliable method for predicting the elastoplasticity behavior and the damage failure behavior of the additive manufacturing metal material are lacked, and the damage failure behavior of the additive manufacturing metal material is difficult to describe due to the complexity of the microstructure of the additive manufacturing metal material, the complexity of the stress state and the complexity of the geometric shape of an additive manufacturing component. Wherein, the extremely high cooling rate and various heat treatment processes in the processing process result in a very complex microstructure of the material, which shows strong anisotropic behavior, i.e. the value of the yield stress is not uniform in all directions; and simultaneously, the material also shows asymmetric hardening behavior in the plastic large deformation process, namely the evolution of stress-strain curves in stretching and compression is inconsistent. Therefore, the method has good engineering application prospect and innovation for establishing the elastoplasticity and damage full-coupling constitutive model based on the complex mechanical behavior of the metal material manufactured by the additive and predicting the elastoplasticity damage failure.
To date, predictions about the elastoplastic damage behavior of additive manufactured metal materials have been mainly based on both micro-crystalline plastic models and phenomenological macro models. The micro model can accurately simulate the evolution of the microstructure of the additive manufacturing metal material, but in the actual simulation calculation process, the rapid increase of the number of units causes low calculation efficiency and high simulation calculation cost. Because most of the additive manufacturing parts are complex configurations which cannot be manufactured by the traditional processing method, a microscopic model represented by a polycrystalline plastic model hardly meets the requirement of efficient calculation. The phenomenological macroscopic constitutive model is a constitutive relation established based on material macroscopic mechanical response, and generally determines material properties through a basic mechanical characterization experiment and utilizes a function to fit a curve of the macroscopic mechanical response. The equation form in the model is relatively simple, so that the calculation speed is high in numerical simulation, and the method is particularly favored in industrial production. However, the existing macroscopic model does not consider the complex mechanical behavior of the additive manufacturing metal material, and the elastoplasticity damage failure behavior of the additive manufacturing metal material cannot be accurately predicted. Therefore, the existing phenomenological macroscopic model and the existing microcosmic crystal plastic model have great limitations, and no accurate and quick method for predicting the elastoplasticity damage failure of the metal material manufactured by the additive has been available.
Disclosure of Invention
Aiming at various limitations of the prior art, the prediction method for the elastoplasticity damage behavior of the metal material manufactured by the additive solves the problem that the calculation speed and the calculation precision cannot be considered in the numerical calculation of the complex-configuration additive manufacturing part; according to the method, observation of a microscopic deformation mechanism and characterization of macroscopic mechanical behavior of the metal material manufactured by the additive are taken as a basis, an anisotropic yield criterion and an asymmetric hardening rule are comprehensively considered, an constitutive relation of stress and strain of the metal material manufactured by the additive is obtained based on a continuous medium damage mechanical theory under an irreversible thermodynamic framework, a constitutive model of elastic-plastic and ductile damage full coupling is further established, and meanwhile, the influence of a loading path on damage failure is taken into consideration in damage evolution by virtue of a Rode angle and a microcrack closing effect. The physical significance of the state variable of the established model is clear, the expression is unique, and the whole deformation process from the elastic-plastic stage to the damage failure of the metal material manufactured by the additive manufacturing can be described, so that the method has high accuracy.
In order to achieve the above object, the method for predicting elastoplasticity damage failure of an additive manufacturing metal material according to the present invention comprises the following specific steps:
s1, establishing an elastic-plastic model capable of describing the anisotropic and asymmetric hardening behaviors of the additive manufacturing metal material.
S2, on the basis of the elastic-plastic model, constructing a strong coupling relation between macroscopic elastic-plastic behaviors and ductility damage, and establishing a full-coupling elastic-plastic damage model of the material increase manufacturing metal material.
S3, predicting the elastoplasticity behavior and the damage failure behavior of the additive manufacturing metal material under different loading paths based on the fully coupled elastoplasticity damage model.
Further: the specific steps of S1 are described as follows:
s11, researching microstructure characteristics of the metal material after additive manufacturing, and researching macroscopic anisotropic behavior through a basic characterization experiment;
s12, introducing a third stress invariant to simultaneously describe the anisotropy of the yield stress in the tensile state and the compressive state on the basis of describing the orthotropic anisotropy based on the nonlinear yield criterion, and establishing a yield equation for describing the anisotropy of the yield stress;
s13, describing the mechanical behavior of the strengthening stage of the metal material by using isotropic hardening and follow-up hardening; introducing a rod angle coefficient into a parameter for controlling hardening, so that the hardening rate of the parameter during tensile and compressive loading is controlled, and an asymmetric hardening model is established;
further: the yield equation describing the yield stress anisotropy established in step S12 is:
Figure BDA0002748782050000031
in the above formula, f is yield criterion, σ is Cauchy stress, X represents stress of follow-up hardening, σyTo yield stress, R is the stress of isotropic hardening, | | σ -X | | fumeJ2Is the yield stress expressed by the second stress invariant, | | σ -X | | purpleJ3Yield stress expressed as a third stress invariant.
Further: the calculation formula for describing the follow-up hardening and the isotropic hardening stress in the step S13 is as follows:
Figure BDA0002748782050000032
R＝Qr，
in the above formula, C is a parameter for controlling the follow-up hardening, α is a strain for the follow-up hardening, Q is a parameter for controlling the isotropic hardening, and r is a strain for the isotropic hardening.
To describe asymmetric hardening, the respective introduction of the respective roeder angle coefficients in Q and C
Figure BDA0002748782050000033
The expression is as follows:
Figure BDA0002748782050000034
Figure BDA0002748782050000035
in the formula, Q1And Q2For the isotropic hardening parameter, C1And C2Tan h is a hyperbolic tangent function for the follow-up hardening parameter.
The elasto-plastic models describing the anisotropic and asymmetric hardening behavior of the additive manufactured metallic material described in S1 include a yield model describing yield stress anisotropy, a calculation model describing follow-up hardening and isotropic hardening stress, and an asymmetric hardening model.
Further: the specific steps of S2 are described as follows:
s21, slowing down the accumulation rate of the damage in the compression state by introducing a micro-crack closing effect, so as to describe different damage behaviors of the material in the stretching and compression states;
s22, on the basis of introducing the micro-crack closing effect, introducing the influence of a Rode angle coefficient in the damage evolution, and establishing a damage accumulation rate model based on a loading path;
s23, based on the principle of total energy equivalence, establishing a full coupling relation between damage and stress strain and hardening, so that the damage influences the elastoplasticity behavior, and establishing a full coupling elastoplasticity damage model.
Further: the calculation formula of the micro-crack closure effect introduced in the step S21 is as follows:
Figure BDA0002748782050000041
where eta represents the stress triaxiality, hvIs a parameter for adjusting eta, tanh is a hyperbolic tangent function, hcThe value range is from 0 to 1, h c0 indicates that the microcracks are all closed, when the effect of slowing the rate of accumulation of damage in the compressed state is greatest, hcWith 1, there is no micro-crack closure effect and no slowing down of the rate of accumulation of damage in the compression path.
Further: the loading path-based damage accumulation rate model in step S22 is:
Figure BDA0002748782050000042
in the above formula, the first and second carbon atoms are,
Figure BDA0002748782050000043
in order to increase the rate of accumulation of damage,
Figure BDA0002748782050000044
is a plastic multiplier, Y represents the damage energy release rate, h is a micro-crack closure effect parameter, k, SsAnd StAre parameters of the lesion.
Further: the model of the full coupling relationship in step S23 is:
cauchy stress and damage coupling: σ ═ 1-hd λetr(εe)1+2μe(1-hd)εe，
Follow-up hardening coupled with damage:
Figure BDA0002748782050000045
isotropic hardening coupled with damage: r ═ 1-hd) Qr,
yield equation of coupling damage:
Figure BDA0002748782050000046
in the above formula, (. epsilon.)eσ) represents elastic strain and cauchy stress, (α, X) represents strain and stress of follow-up hardening, (R, R) represents strain and stress of isotropic hardening, d is a factor representing damage, and the value ranges from 0 to 1; when d is 0, the damage is not damaged, and when d is 1, the material is completely damaged and fails.
Further: the specific steps of S3 are described as follows:
s31, solving the established model through a numerical algorithm of backspacing mapping, and compiling a VUMAT user subprogram;
s32, determining a parameter calibration experimental scheme, and calibrating material parameters in the fully-coupled elastoplastic damage model;
and S33, carrying out finite element numerical simulation of the additive manufacturing metal material under different loading paths.
In the step S31, the calculation of the finite element displacement field adopts a dynamic display algorithm; and the internal state variables adopt a complete implicit constitutive integral process to establish a basic numerical algorithm framework of elastic prediction-shaping correction, and updated generalized stress and the like are kept on the yield surface through a return algorithm. And calculating nonlinear increments of all state variables (Cauchy stress, isotropic hardening, follow-up hardening, damage and the like) in the elastic-plastic damage model through a Newton-Raphson algorithm, wherein when a yield equation is less than zero, the elastic trial stress is positioned in a yield plane, the strain increment is full elasticity and does not generate new plastic deformation, and the value of the damage in the nth step is the final damage value. Otherwise, the generalized stress and internal variables need to be updated through a plasticity correction process.
In step S32, the elastic parameter, the anisotropic parameter, the hardening parameter, and the damage parameter are calibrated step by step.
In the step S33, numerical simulations of elastic-plastic behavior and damage failure in the tensile, compressive and shear paths are mainly performed, and the yield surface, stress-strain curves of different loading paths, damage accumulation, and failure strain traces of the additive manufacturing metal material are predicted and compared with other classical models.
The invention has the beneficial effects that: the method establishes a full-coupling elastoplasticity damage constitutive model, and develops an iterative algorithm to carry out numerical calculation on the metal material manufactured by the additive manufacturing. The initial anisotropy and the asymmetric hardening behavior are considered in the established model, the damage failure of the additive manufacturing metal material under different loading paths is predicted on the basis, an effective method for predicting the mechanical property of the additive manufacturing metal material is explored, and theoretical guidance and a basis for optimizing the machining process are provided for the product performance evaluation of the additive manufacturing parts. Respectively researching the complex mechanical behavior of the metal material manufactured by the additive, further researching the relation between the complex plastic behavior and the damage failure, providing a parameter calibration scheme, and predicting the elastoplastic behavior and the damage failure under different loading paths based on the calibrated parameters. The method disclosed by the invention is used for conducting numerical simulation and damage failure prediction on the metal material manufactured by the additive manufacturing based on the fully-coupled elastoplasticity damage model, is a reliable and efficient calculation model and prediction method, and has important scientific innovativeness and engineering application value in the establishment of related models.
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FIG. 1 is a flow chart of the present invention;
FIG. 2 is a schematic diagram of a sample from an additive manufacturing metal material characterization experiment in this example;
FIG. 3 is a flow chart of parameter calibration in the present embodiment;
FIG. 4 is a comparison of the predicted yield surface and experimental values for this example;
FIG. 5 is a graph of stress-strain curves in tension and compression for an additive manufactured metallic material as predicted in this example;
FIG. 6 is a graph of cumulative amount of damage as a function of plastic strain under tensile and compressive loading paths;
fig. 7 shows the predicted failure strain traces under different loading paths in this embodiment.
Detailed Description
The present invention is described in further detail below with reference to embodiments of the drawings so that those skilled in the art can understand the entire contents of the present invention.
Example 1:
the method for predicting the elastoplasticity damage failure of the additive manufacturing metal material comprises the following steps:
s1, establishing an elastic-plastic model capable of describing the anisotropic and asymmetric hardening behaviors of the additive manufacturing metal material.
Further: the specific steps of S1 are described as follows:
s11, researching microstructure characteristics of the metal material after additive manufacturing, and researching macroscopic anisotropic behavior through a basic characterization experiment; as shown in fig. 2, when the samples are selected, the samples are respectively sampled according to the horizontal direction and the vertical direction of the additive building direction.
S12, introducing a third stress invariant to simultaneously describe the anisotropy of the yield stress in the tensile state and the compressive state on the basis of describing the orthotropic anisotropy based on the nonlinear yield criterion, and establishing a yield equation for describing the anisotropy of the yield stress;
Figure BDA0002748782050000061
in the above formula, f is yield criterion, σ is Cauchy stress, X represents stress of follow-up hardening, σyTo yield stress, R is the stress of isotropic hardening, | | σ -X | | fumeJ2Is the yield stress expressed by the second stress invariant, | | σ -X | | purpleJ3Yield stress expressed as a third stress invariant.
S13, describing the mechanical behavior of the strengthening stage of the metal material by using isotropic hardening and follow-up hardening; introducing a rod angle coefficient into a parameter for controlling hardening, so that the hardening rate of the parameter during tensile and compressive loading is controlled, and an asymmetric hardening model is established; the calculation formula for describing the follow-up hardening and the isotropic hardening stress is as follows:
Figure BDA0002748782050000062
R＝Qr，
in the above formula, C is a parameter for controlling the follow-up hardening, α is a strain for the follow-up hardening, Q is a parameter for controlling the isotropic hardening, and r is a strain for the isotropic hardening.
To describe asymmetric hardening, the introduction of the respective roeder angle coefficients in Q and C
Figure BDA0002748782050000071
The expression is as follows:
Figure BDA0002748782050000072
Figure BDA0002748782050000073
in the above formula, Q1And Q2For the isotropic hardening parameter, C1And C2Tan h is a hyperbolic tangent function for the follow-up hardening parameter.
When in use
Figure BDA0002748782050000074
When the load is applied, the parameter Q is Q for controlling the isotropic hardening1+Q2Controlling the parameter C ═ C of follow-up hardening1+C2The stress value of the isotropic hardening and the follow-up hardening is R ═ (Q)1+Q2) r and
Figure BDA0002748782050000075
when in use
Figure BDA0002748782050000076
When the strain is applied, the strain indicates the state of strain, and the constant curing parameter Q is controlled to be Q1Controlling the parameter C ═ C of follow-up hardening1Stress value of isotropic hardening and follow-up hardening is R ═ Q1r and
Figure BDA0002748782050000077
it can be seen that by this method it is achieved that the hardening takes different stress values in tension and compression, thereby achieving asymmetryAn accurate description of the hardening.
Further: the specific steps of S2 are described as follows:
s21, slowing down the accumulation rate of the damage in the compression state by introducing a micro-crack closing effect, so as to describe different damage behaviors of the material in the stretching and compression states;
further: the calculation formula of the micro-crack closure effect introduced in the step S21 is as follows:
Figure BDA0002748782050000078
where eta represents the stress triaxiality, hvIs a parameter that adjusts η, and tanh is a hyperbolic tangent function.
Under the condition of uniaxial tension load, the stress triaxial degree eta is 1/3, and a large parameter h is taken and putv10, h 1 indicates no microcrack closure effect; under the shearing load, the stress triaxial degree eta is equal to 0, and the amplification parameter h is also takenv＝10，
Figure BDA0002748782050000079
Under the unidirectional compression load, the stress triaxial degree eta is-1/3, and the amplification parameter h is also takenv＝10，h＝hc，hcThe value range is from 0 to 1, h c0 indicates that the microcracks are all closed, when the effect of slowing the rate of accumulation of damage in the compressed state is greatest, hcWith 1, there is no micro-crack closure effect and no slowing down of the rate of accumulation of damage in the compression path.
S22, introducing the influence of a Rode angle coefficient in the damage evolution on the basis of introducing the micro-crack closing effect, and establishing a damage evolution rate model based on a loading path;
further: the calculation formula of the damage accumulation rate in step S22 is:
Figure BDA0002748782050000081
in the above formula, the first and second carbon atoms are,
Figure BDA0002748782050000082
in order to increase the rate of accumulation of damage,
Figure BDA0002748782050000083
is a plastic multiplier, Y represents the damage energy release rate, h is a micro-crack closure effect parameter, k, SsAnd StAre parameters of the lesion.
When in use
Figure BDA0002748782050000084
Time, representing the loading state of the tension, the rate of damage accumulation
Figure BDA0002748782050000085
When in use
Figure BDA0002748782050000086
Time, representing the loading state of the shear, the rate of damage accumulation
Figure BDA0002748782050000087
Respectively to the damage parameter SsAnd StDifferent values are taken, so that the precise description of the damage under the stretching and shearing loading paths can be realized.
S23, based on the principle of total energy equivalence, establishing a full coupling relation between damage and stress strain and hardening, so that the damage influences the elastoplasticity behavior, and establishing a full coupling elastoplasticity damage model.
Further: the expression of the full coupling relationship in step S23 is:
cauchy stress and damage coupling: σ ═ 1-hd λetr(εe)1+2μe(1-hd)εe，
Follow-up hardening coupled with damage:
Figure BDA0002748782050000088
isotropic hardening coupled with damage: r ═ 1-hd) Qr,
yield equation of coupling damage:
Figure BDA0002748782050000089
in the above formula, λeAnd mueIs Lame constant, (. epsilon.) (eσ) represents elastic strain and cauchy stress, (α, X) represents strain and stress of follow-up hardening, (R, R) represents strain and stress of isotropic hardening, d is a factor representing damage, and the value ranges from 0 to 1; when d-0 is indicative of no damage, and when d-1 is indicative of complete failure of the material.
S3, predicting the elastoplasticity behavior and the damage failure behavior of the additive manufacturing metal material under different loading paths based on the fully coupled elastoplasticity damage model.
Further: the specific steps of S3 are described as follows:
s31, solving the established model through a proper numerical algorithm, wherein the finite element displacement overall field is calculated by adopting a dynamic display algorithm; and the local state variables adopt a complete implicit constitutive integral process, a basic numerical algorithm framework of elastic prediction-shaping correction is established, and updated generalized stress and the like are kept on the yielding surface through a return algorithm. Calculating nonlinear increments of all state variables (Cauchy stress, isotropic hardening, follow-up hardening, damage and the like) in the elastoplastic damage model by a Newton-Raphson algorithm, wherein the specific calculation process comprises the following steps:
in the elastic prediction, the plastic increment of strain delta epsilon p0, then calculating the test stress
Figure BDA0002748782050000091
The value of the test stress is brought into the yield equation when the yield equation
Figure BDA0002748782050000092
And the elastic test stress is positioned in the yield plane, the strain increment is full elasticity and does not generate new plastic deformation, and the value of the damage in the nth step is the final damage value. Otherwise, the generalized stress and internal variables need to be updated through a plasticity correction process.
Compiling a VUMAT user subprogram in the whole numerical algorithm process through a Fortran compiler, and embedding the VUMAT user subprogram into ABAQUS for finite element structure analysis;
s32, determining a parameter calibration experimental scheme, and calibrating material parameters in the fully-coupled elastoplastic damage model. As shown in fig. 3, the elastic parameters, the anisotropic parameters, the hardening parameters and the damage parameters are calibrated step by step, the elastic parameters are directly measured from the slope of the elastic stage of the unidirectional stretching, the anisotropic parameters require yield stress in different directions, the hardening parameters need to be fitted with an AB-segment curve during the unidirectional stretching, the damage parameters need to be calibrated by being fitted with a CD-segment of a stress-strain curve, and the specifically calibrated parameter values are shown in table 1.
TABLE 1 calibration of model parameters
Figure BDA0002748782050000093
S33, elastic-plastic behavior and damage failure prediction of the additive manufacturing metal material under different loading paths are carried out.
The yield stress and the strain to failure of the additive manufacturing metal material according to the present embodiment are shown in table 2. And performing numerical simulation on the elastoplasticity damage behaviors under different loading paths based on the model parameters marked in the S32, mainly verifying the elastoplasticity behaviors and damage failure under different loading paths, and verifying the conformity degree of the experimental result and the simulation prediction result. Fig. 4 is a comparison between a yield surface predicted by the model and an experimental value, and it can be seen that the model of this embodiment accurately predicts the yield stress of the additive manufacturing metal material in the horizontal building tensile direction, the yield stress in the vertical direction, and the yield stress in the compressive loading, whereas the classic misses yield equation can only predict the yield stress in the horizontal tensile direction, so that the model of this embodiment can accurately predict the anisotropic behavior of the yield stress of the additive manufacturing metal material. As shown in fig. 3, stress-strain curves of an additive manufacturing metal material during stretching and compressing are greatly different, a result of predicting a microcrack closure effect is not considered to be greatly different from a compressive failure strain measured by an experiment, a result of predicting asymmetric hardening is not considered to be matched with a compressive stress-strain curve, only the model provided by the embodiment can accurately predict mechanical properties such as yield stress and strength limit during stretching and compressing, and the model is well consistent with the experiment result, so that the model provided by the embodiment can accurately simulate the asymmetric hardening behavior of the additive manufacturing metal material during stretching and compressing. As can be seen from the accumulated process of damage along with plastic strain shown in fig. 6, the different evolution rates of the damage of the additive manufacturing metal material in the tensile and compressive states can be accurately described, and the predicted tensile and compressive failure strains are in good agreement with the experimental values. As shown in fig. 7, the method established in this embodiment can accurately predict the failure strain values of the additive manufacturing metal material under different loading paths, and the classical model predicts the same failure strain under tension, compression and shear, so that only one loading path can be followed, and the failure strain trajectory predicted by the model in this embodiment can realize accurate prediction of different failure strains under tension, compression and shear.
TABLE 1 mechanical Properties of certain additive manufacturing Metal materials
Figure BDA0002748782050000101
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.

Claims (3)

1. An elastoplasticity damage failure prediction method for an additive manufacturing metal material is characterized by comprising the following steps:
s1, establishing an elastic-plastic model capable of describing the anisotropic and asymmetric hardening behaviors of the additive manufacturing metal material;
s2, on the basis of the elastic-plastic model, constructing a strong coupling relation between macroscopic elastic-plastic behaviors and ductility damage, and establishing a full-coupling elastic-plastic damage model of the material increase manufacturing metal material;
s3, predicting the elastoplasticity behavior and the damage failure behavior of the additive manufacturing metal material under different loading paths based on the fully coupled elastoplasticity damage model.
Further: the specific steps of S1 are described as follows:
s11, researching microstructure characteristics of the metal material after additive manufacturing, and researching macroscopic anisotropic behavior through a basic characterization experiment;
s12, introducing a third stress invariant to simultaneously describe the anisotropy of the yield stress in the tensile state and the compressive state on the basis of describing the orthotropic anisotropy based on the nonlinear yield criterion, and establishing a yield equation for describing the anisotropy of the yield stress;
s13, describing the mechanical behavior of the strengthening stage of the metal material by using isotropic hardening and follow-up hardening; a Rode angle coefficient is introduced into the parameters for controlling the hardening, so that the Rode angle coefficient controls the hardening rate under the tension and compression loading, and an asymmetric hardening model is established.
Further: the specific steps of S2 are described as follows:
s21, slowing down the accumulation rate of the damage in the compression state by introducing a micro-crack closing effect, so as to describe different damage behaviors of the material in the stretching and compression states;
s22, on the basis of introducing the micro-crack closing effect, introducing the influence of a Rode angle coefficient in the damage evolution, and establishing a damage accumulation rate model based on a loading path;
s23, based on the principle of total energy equivalence, establishing a full coupling relation between damage and stress strain and hardening, so that the damage influences the elastoplasticity behavior, and establishing a full coupling elastoplasticity damage model. Further: the specific steps of S3 are described as follows:
s31, solving the established model through a numerical algorithm of backspacing mapping, and compiling a VUMAT user subprogram;
s32, determining a parameter calibration experimental scheme, and calibrating material parameters in the fully-coupled elastoplastic damage model;
and S33, carrying out finite element numerical simulation of the additive manufacturing metal material under different loading paths.
In the step S31, the calculation of the finite element displacement field adopts a dynamic display algorithm; and the internal state variables adopt a complete implicit constitutive integral process to establish a basic numerical algorithm framework of elastic prediction-shaping correction, and updated generalized stress and the like are kept on the yield surface through a return algorithm. Calculating nonlinear increments of all Kouchy stresses, isotropic hardening, follow-up hardening and damages in an elastic-plastic damage model through a Newton-Raphson algorithm, wherein when a yield equation is less than zero, an elastic trial stress is positioned in a yield surface, the strain increment is full elasticity and does not generate new plastic deformation, the value of the damage in the nth step is a final damage value, and otherwise, a generalized stress and an internal variable need to be updated through a plastic correction process;
in the step S32, calibrating the elastic parameter, the anisotropic parameter, the hardening parameter and the damage parameter step by step;
in the step S33, numerical simulations of elastic-plastic behavior and damage failure under the tensile, compressive and shear paths are developed, and the yield surface, stress-strain curves of different loading paths, damage accumulation and failure strain trajectory of the additive manufacturing metal material are predicted.
2. The method of claim 1, wherein the method comprises predicting the elasto-plastic damage failure of the additive manufactured metallic material
The yield model describing the yield stress anisotropy established in step S12 is:
Figure FDA0002748782040000021
in the above formula, f is yield criterion, σ is Cauchy stress, X represents stress of follow-up hardening, σyTo yield stress, R is the stress of isotropic hardening, | | σ -X | | fumeJ2Is the yield stress expressed by the second stress invariant, | | σ -X | | purpleJ3Yield stress expressed as a third stress invariant;
the calculation model describing the follow-up hardening and the isotropic hardening stress in the step S13 is:
Figure FDA0002748782040000022
R＝Qr，
in the formula, C is a parameter for controlling follow-up hardening, alpha is strain of follow-up hardening, Q is a parameter for controlling isotropic hardening, and r is strain of isotropic hardening;
to describe asymmetric hardening, the respective introduction of the respective roeder angle coefficients in Q and C
Figure FDA0002748782040000023
The asymmetric hardening model is established as follows:
Figure FDA0002748782040000024
Figure FDA0002748782040000025
in the formula, Q1And Q2For the isotropic hardening parameter, C1And C2Tan h is a hyperbolic tangent function for the follow-up hardening parameter.
3. The method of predicting elasto-plastic damage failure of an additive manufactured metallic material according to claim 1, wherein the computational model of the micro-crack closure effect introduced in step S21 is:
Figure FDA0002748782040000031
where eta represents the stress triaxiality, hvIs a parameter for adjusting eta, tanh is a hyperbolic tangent function, hcThe value range is from 0 to 1, hc0 indicates that the microcracks are all closed, when the effect of slowing the rate of accumulation of damage in the compressed state is greatest, hcWith 1, there is no micro-crack closure effect and no slowing down of the rate of accumulation of damage in the compression path.
Further: the damage accumulation rate model based on the loading path in step S22 is:
Figure FDA0002748782040000032
in the above formula, the first and second carbon atoms are,
Figure FDA0002748782040000033
in order to increase the rate of accumulation of damage,
Figure FDA0002748782040000034
is a plastic multiplier, Y represents the damage energy release rate, h is a micro-crack closure effect parameter, k, SsAnd StAre parameters of the lesion.
Further: the model of the full coupling relationship in step S23 is:
cauchy stress and damage coupling: σ ═ 1-hd λetr(εe)1+2μe(1-hd)εe，
Follow-up hardening coupled with damage:
Figure FDA0002748782040000035
isotropic hardening coupled with damage: r ═ 1-hd) Qr,
yield equation of coupling damage:
Figure FDA0002748782040000036
in the above formula, (. epsilon.)eσ) represents elastic strain and cauchy stress, (α, X) represents strain and stress of follow-up hardening, (R, R) represents strain and stress of isotropic hardening, d is a factor representing damage, and the value ranges from 0 to 1; when d is 0, the damage is not damaged, and when d is 1, the material is completely damaged and fails.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114201897A (en) * 2021-12-06 2022-03-18 上海交通大学 Metal sheet edge cracking prediction considering blanking history
CN114692318A (en) * 2022-06-01 2022-07-01 中国飞机强度研究所 Grid type fuel tank structure damage resistance assessment method for airplane impact dynamics test
CN114912314A (en) * 2022-04-21 2022-08-16 中国科学院武汉岩土力学研究所 Implicit self-adaptive stress integral calculation method for rock-soil medium elastic-plastic constitutive relation

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109492277A (en) * 2018-10-25 2019-03-19 哈尔滨工程大学 A method of estimation metal increasing material manufacturing ultrasonic implement treatment acts on layer depth
CN111709176A (en) * 2020-07-27 2020-09-25 上海圣之尧智能科技有限公司 Finite element simulation method and system considering plasticity and damage constitutive relation
US20200331102A1 (en) * 2017-09-08 2020-10-22 University Public Corporation Osaka Method and Apparatus for Analyzing Additively Manufactured Object, and Method and Apparatus for Additively Manufacturing an Object

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200331102A1 (en) * 2017-09-08 2020-10-22 University Public Corporation Osaka Method and Apparatus for Analyzing Additively Manufactured Object, and Method and Apparatus for Additively Manufacturing an Object
CN109492277A (en) * 2018-10-25 2019-03-19 哈尔滨工程大学 A method of estimation metal increasing material manufacturing ultrasonic implement treatment acts on layer depth
CN111709176A (en) * 2020-07-27 2020-09-25 上海圣之尧智能科技有限公司 Finite element simulation method and system considering plasticity and damage constitutive relation

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
KAI ZHANG .ETC: "Effect of yield surface distortion on the failure prediction of Mg alloy sheets", 《SPRINGER》 *
杨海峰: "表征镁合金各向异性屈服行为和应变率影响的本构模型研究", 《北京交通大学学位论文》 *
黄西成 等: "金属材料在复杂的塑性变形下损伤积累与破坏", 《中国工程物理研究院科技年报》 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114201897A (en) * 2021-12-06 2022-03-18 上海交通大学 Metal sheet edge cracking prediction considering blanking history
CN114912314A (en) * 2022-04-21 2022-08-16 中国科学院武汉岩土力学研究所 Implicit self-adaptive stress integral calculation method for rock-soil medium elastic-plastic constitutive relation
CN114912314B (en) * 2022-04-21 2024-04-02 中国科学院武汉岩土力学研究所 Implicit self-adaptive stress integral calculation method for elastoplastic constitutive relation of rock-soil medium
CN114692318A (en) * 2022-06-01 2022-07-01 中国飞机强度研究所 Grid type fuel tank structure damage resistance assessment method for airplane impact dynamics test

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