Issue with HCP alloy during tensile process
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刘淼
Jun 16, 2025, 9:16:48 PMJun 16
to Prisms-CPFE-users
Hello everyone, I am trying to simulate the tensile process of Ti alloy using Prisms. Currently, the results match well in the elastic stage, but show abnormal linear increase after the yield limit. I am constantly adjusting the parameters through NSGA-iii optimization, but this problem persists. I am unable to determine whether the problem lies in the RVE or the boundary conditions. I would be very grateful for any suggestions for modification.
BC:# Heder lines = 2
# FaceID DoF FinalDisplacement
5 1 0
5 2 0
5 3 0
6 3 0.08
BC:# Heder lines = 2
# FaceID DoF FinalDisplacement
5 1 0
5 2 0
5 3 0
6 3 0.08
prmFile:
# Listing of Parameters
# ---------------------
####################################
# FE parameters
####################################
# Basis function interpolation order (1-linear)
set Order of finite elements = 1
# Quadrature point order n^3 (2->8 quadrature points)
set Order of quadrature = 2
####################################
# Domain parameters
####################################
# Number of physical dimensions for the simulation
set Number of dimensions = 3
# The size of the domain in the x direction.
set Domain size X = 1
# The size of the domain in the y direction.
set Domain size Y = 1
# The size of the domain in the z direction.
set Domain size Z = 1
####################################
# Mesh parameters
####################################
# The number of mesh subdivisions in the x direction.
set Subdivisions X = 64
# The number of mesh subdivisions in the y direction.
set Subdivisions Y = 64
# The number of mesh subdivisions in the z direction.
set Subdivisions Z = 64
# The number of initial refinements of the coarse mesh.
set Refine factor = 0
# Only written for serial runs and if number of elements < 10000
set Write Mesh To EPS = false
####################################
# Solver output parameters
####################################
# Flag to write output vtu and pvtu files
set Write Output = false
# Output Directory
# Need to create directory before using this. Will be corrected in future versions of the software
set Output Directory = results
# Skip Output Steps
set Skip Output Steps = 300
# Output Equivalent strain
set Output Equivalent strain = true
# Output Equivalent stress
set Output Equivalent stress = true
# Output Grain ID
set Output Grain ID = true
# Output Twin fractions
set Output Twin fractions = true
# Flag to write quadrature output
set Write Quadrature Output = true
# Skip Quadrature Output Steps
set Skip Quadrature Output Steps = 100
####################################
# Boundary condition information
####################################
#File name containing BC information
set Boundary condition filename = BCinfo.txt
#BC file number of header lines
set BC file number of header lines = 2
#Number of boundary conditions
set Number of boundary conditions = 4
####################################
# Solver parameters
####################################
#delta T for every increment
set Time increments = 0.001
#Total simulation time
set Total time = 8
# Maximum iterations for linear solver
set Maximum linear solver iterations = 100000
# Relative linear solver tolerance
set Relative linear solver tolerance = 1.0e-9
# Maximum no. of non-linear iterations
set Maximum non linear iterations = 4
########################################################################
####################################
# Flag to indicate if User Material Model is enabled
set Enable User Material Model = true
# Flag to indicate if User Material Model is enabled Phase 1
set Enable User Material Model 1 = true
# Number of User Material Constants in a Material model Phase 1
set Number of User Material Constants 1 = 12
# Number of User Material State Variables in a Material model Phase 1
set Number of User Material State Variables 1 = 76
# Material Constants in a Material model Phase 1
set User Material Constants 1 = 1.0e-3, 0.026, 1.0e-4, 1.0e-4, 100, 100, 100040, 67450, 12720, 15970, 40,30
# Material State Variables in a Material model Phase 1
set User Material State Variables Initial Values 1 =0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
####################################
# Elasticity parameters
####################################
# Elastic Stiffness Matrix -Voigt Notation (MPa)
set Elastic Stiffness row 1 = 162.4e3, 92e3, 92e3, 0, 0, 0
# Elastic Stiffness Matrix -Voigt Notation (MPa)
set Elastic Stiffness row 2 = 92e3, 162.4e3, 92e3, 0, 0, 0
# Elastic Stiffness Matrix -Voigt Notation (MPa)
set Elastic Stiffness row 3 = 92e3, 92e3, 162.4e3, 0, 0, 0
# Elastic Stiffness Matrix -Voigt Notation (MPa)
set Elastic Stiffness row 4 = 0, 0, 0, 49.7e3, 0, 0
# Elastic Stiffness Matrix -Voigt Notation (MPa)
set Elastic Stiffness row 5 = 0, 0, 0, 0, 49.7e3, 0
# Elastic Stiffness Matrix -Voigt Notation (MPa)
set Elastic Stiffness row 6 = 0, 0, 0, 0, 0, 49.7e3
####################################
# Slip parameters
####################################
# Number of Slip Systems
set Number of Slip Systems = 18
# Latent Hardening Ratio
set Latent Hardening Ratio filename = LatentHardeningRatio.txt
# RSS of the slip sytems
set Initial Slip Resistance = 320,320,320, 410,410,410, 1040,1040,1040,1040,1040,1040, 1040,1040,1040,1040,1040,1040
# Heardening moduli of slip systems
set Initial Hardening Modulus = 460,460,460, 460,460,460, 460,460,460,460,460,460, 460,460,460,460,460,460
# Power law coefficient
set Power Law Exponent = 1.49,1.49,1.49, 1.49,1.49,1.49, 1.49,1.49,1.49,1.49,1.49,1.49, 1.49,1.49,1.49,1.49,1.49,1.49
# Saturation stress
set Saturation Stress = 1100,1100,1100, 1100,1100,1100, 1100,1100,1100,1100,1100,1100, 1100,1100,1100,1100,1100,1100
# Slip Directions File
set Slip Directions File = slipDirections.txt
# Slip Normals File
set Slip Normals File = slipNormals.txt
####################################
# Twin parameters
####################################
#Flag to indicate if cyclic loading is enabled
set Twinning enabled = true
# Number of Twin Systems
set Number of Twin Systems = 6
# Initial CRSS of the twin sytems
set Initial Slip Resistance Twin = 860,860,860,860,860,860
# Hardening moduli of twin systems
set Initial Hardening Modulus Twin = 860,860,860,860,860,860
# Power law exponents of twin systems
set Power Law Exponent Twin = 2.64,2.64,2.64,2.64,2.64,2.64
# Saturation stress of twin systems
set Saturation Stress Twin = 1100,1100,1100,1100,1100,1100
# Twin growth saturation factor (<(1-twinThresholdFraction))
set Twin Saturation Factor = 0.3
# Threshold fraction of characteristic twin shear (<1)
set Twin Threshold Fraction = 0.4
# Twin Directions File
set Twin Directions File = twinDirections.txt
# Twin Normals File
set Twin Normals File = twinNormals.txt
# characteristic twin shear
set Characteristic Twin Shear = 0.18
####################################
# Constitutive model parameters
####################################
# Stress tolerance for the yield surface (MPa)
set Stress Tolerance = 1.0e-9
# Maximum no. of active slip search iterations
set Max Slip Search Iterations = 1
# Maximum no. of iterations to achieve non-linear convergence
set Max Solver Iterations = 1
####################################
# Input microstructure
####################################
# Number of voxels in x direction
set Voxels in X direction = 32
# Number of voxels in y direction
set Voxels in Y direction = 32
# Number of voxels in z direction
set Voxels in Z direction = 32
# Grain ID file name
set Grain ID file name = grainID.txt
# Number of header Lines in grain ID file
set Header Lines GrainID File = 20
# Grain orientations file name
set Orientations file name = orientations.txt
刘淼
Jun 16, 2025, 9:54:48 PMJun 16
to Prisms-CPFE-users
And this is the simulated result without using the user materials constant, some cases are reasonable. All simulation using the same RVE and BCs.
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