DEFORM-3D Keyword Documentation Part 6 ppt

A Material constant None n Strain rate sensitivity index None R Gas constant 8.3144E+03 N*mm/g-mole/K material flow stress n strain rate sensitivity index  H activation energy N-mm/

10.00 26.36 31.53 33.79

Table A.2 Flow stress of material 3 at T = 2000 F

Strain Strain Rate

Material Material number None

Ftype Function type None

= 4

 Material constant None

 H Activation energy None

A Material constant None

n Strain rate sensitivity index None

R Gas constant 8.3144E+03 (N-mm/g-mole/K)

material flow stress

n strain rate sensitivity index

 H activation energy (N-mm/mole) or (Btu/mole)

R gas constant

Tabs absolute temperature

This flow stress function is used primarily for aluminum alloys

Applicable simulation types: Isothermal Deformation

OPERAND DESCRIPTION DEFAULT

Material Material number None

Ftype Function type None

= 5

 H Activation energy None

A Material constant None

n Strain rate sensitivity index None

R Gas constant 8.3144E+03 (N*mm/g-mole/K)

material flow stress

n strain rate sensitivity index

 H activation energy (N-mm/mole) or (Btu/mole)

R gas constant

Tabs absolute temperature

This flow stress function is used primarily for aluminum alloys

Applicable simulation types: Isothermal Deformation

Non-Isothermal Deformation

RELATED TOPICS

Flow stress, Plastic object

FSTRES

fs = f(strain, atom, temp.)

FSTRES Material, Ftype

Nstrain, Natom, Ntemp

Stress(Nstrain, Nsrate, Ntemp)

OPERAND DESCRIPTION DEFAULT

Material Material number None

Ftype Function type None

= 7 log interpolation of strain

= 8 linear interpolation of strain

Nstrain Number of strain sampling points None

Natom Number of atom sampling points None

Ntemp Number of temperature sampling points None

Strain(i) Strain at ith sampling point None

Satom(j) Strain rate at jth sampling point None

Temp(k) Temperature at kth sampling point None

Stress(i, j, k) Flow stress at ith, jth, kth sampling point None (((Stress(i, j, k), i = 1, Nstrain), j = 1, Nsatom), k = 1, Ntemp)

FSTRES

(Generalized Johnson & Cook)

where:

FSTRES Material, Ftype

0, E, n, m,

Alpha, Beta, Eps0, Troom, Tmelt, Tb, k

OPERAND DESCRIPTION DEFAULT

Material Material number None

Ftype Flow stress type None

= 9 (Generalized Johnson & Cook, usually for machining)

0, E, n, m, Alpha, Beta, k, Tb Material parameters 0

Eps0 Reference strain rate 0

Troom, Tmelt Room temperature and melt temperature None

DEFINITION

FSTRES specifies the flow stress for a particular material

REMARKS

In above equations for FSTRES function Ftype =9 :

: material strain rate

: material flow stress

T : temperature

This flow stress function is used primarily for machining applications

Applicable simulation types: Isothermal Deformation

OPERAND DESCRIPTION DEFAULT

Material Material number None

Ftype Flow stress type None

REMARKS

In above equations for FSTRES function Ftype = 10 :

: material strain rate

: material flow stress

T : temperature

This flow stress function is used primarily for machining applications

Applicable simulation types: Isothermal Deformation

OPERAND DESCRIPTION DEFAULT

Material Material number None

Ftype Flow stress type None

FSTRES Material, Ftype

OPERAND DESCRIPTION DEFAULT

Material Material number None

Ftype Function type None

= -n n is the user subroutine number

Non-Isothermal Deformation

RELATED TOPICS

Flow stress, User subroutine, Plastic Object

GENCTC

GENCTC Tolerance

OPERAND DESCRIPTION DEFAULT

Tolerance Contact tolerance value 0.0001

GENDB

GENDB DbMode Dummy KeepPositiveStpNo

DbFilename

OPERAND DESCRIPTION DEFAULT

DbMode = 1 Generate old database

= 2 Generate new database

Dummy Dummy for historical reasons

KeepPositiveStpNo Whether to keep positive step # 0

=0: generate negative step # always

=1: keep positive step #

DbFilename Database file name to be generated

GEOERR

GEOERR Res, Ren

OPERAND DESCRIPTION DEFAULT

Res Relative error limit in tangential direction 1.0 E-06

Ren Relative error limit in normal direction 1.0 E-04

DEFINITION

GEOERR specifies the values of error limits in geometry handling

REMARKS

The DEFORM system calculates the overall geometry size, geosiz, and the

absolute error limits in tangential and normal directions are determined by

aes = geosiz * Res

aen = geosiz * Ren

Geometric lengths smaller that aes and aen are neglected

GRAIN

GRAIN Object, Nelm, Nvar, Default

Element(1), Pre_StrnR (1), Xrex(1), Avg_GS(1), Init_GS(1), RtnStrn(1), Dm_Time(1),

Dm_StrnR(1), Dm_Temp(1), Pk_Strn(1), Elv_Md(1), Xrex_D(1), Xrex_M(1), Xrex_S(1),

Rex_GS_D(1), Rex_GS_M(1), Rex_GS_S(1)

Element(Nelm), Pre_StrnR(Nelm), Xrex(Nelm), Avg_GS(Nelm), Init_GS(Nelm), RtnStrn(Nelm),

Dm_Time(Nelm), Dm_StrnR(Nelm), Dm_Temp(Nelm), Pk_Strn(Nelm), Elv_Md (Nelm),

Xrex_D(Nelm), Xrex_M(Nelm), Xrex_S(Nelm), Rex_GS_D(Nelm), Rex_GS_M(Nelm), Rex_GS_S(Nelm)

Nvar Number of grain-related variables (16 currently) None

NOTE: (i) stands for the ith element below

Element(i) Element number

Pre_StrnR(i) Previous strain rate (used for determining

deformation status)

Xrex(i) Percentage of recrystallization

Avg_GS(i) Average grain size

Init_GS(i) Initial grain size

RtnStrn(i) Retained Strain

Dm_Time(i) Time span of deformation

Dm_StrnR(i) Average strain rate over deformation period

Dm_Temp(i) Average temperature over deformation period

Pk_Strn(i) Peak strain

ElvMd(i) grain evolution mode for the ith element

Xrex_D(i) Dynamic recrystallization percentage

Xrex_M(i) Meta-dynamic recrystallization percentage

Xrex_S(i) Static recrystallization percentage

Rex_GS_D(i) Grain size of dynamically recrystallized grains

Rex_GS_M(i) Grain size of meta-dynamically recrystallized grains

Rex_GS_S(i) Grain size of statically recrystallized grains

Keywords: GRNDAT

OPERAND DESCRIPTION DEFAULT

Mtl# Material Number None

Model# Model Number 1

= 1, current model

= -n, User’s routine

SRB_Flg Flag for Strain Rate Boundary between static and meta-dynamic

= 1, Computed with equation (1), material data functions of temperature

= 2, Computed with equation (1), material data functions of strain rate

SRB_Var(i) Temperature or strain rate of the ith sampling point for

PS_Flg Flag for Peak Strain p and Critical Strain c

= 1, Computed with equation (12-13), material data functions of temperature

= 2, Computed with equation (12-13), material data functions of strain rate

PS_Var(i) Temperature or strain rate of the ith sampling point for Peak Strain p and Critical Strain c

SRK_Flg Flag for Static Recrystallization Kinetics

= 1, Computed with equation (2-4), material data functions of temperature

= 2, Computed with equation (2-4), material data functions of strain rate

SRK_Var(i) Temperature or strain rate of the ith sampling point for Static Recrystallization Kinetics

SRGS_Flg Flag for Static Recrystallized Grain Size

= 1, Computed with equation (5-6), material data functions of temperature

= 2, Computed with equation (5-6), material data functions of strain rate

SRGS_Var(i) Temperature or strain rate of the ith sampling point for Statically Recrystallized Grain Size

MRK_Flg Flag Meta-dynamic Recrystallization Kinetics

= 1, Computed with equation (7-9), material data functions of temperature

= 2, Computed with equation (7-9), material data functions of strain rate

MRK_Var(i) Temperature or strain rate of the ith sampling point for Meta-dynamic Recrystallization

Kinetics

MRGS_Flg Flag for Meta-dynamic Recrystallized Grain Size

= 1, Computed with equation (10-11), material data functions of temperature

= 2, Computed with equation (10-11), material data functions of strain rate

MRGS_Var(i) Temperature or strain rate of the ith sampling point for Meta-dynamically Recrystallized

Grain Size

DRK_Flg Flag Dynamic Recrystallization Kinetics

= 1, Computed with equation (15-17), material data functions of temperature

= 2, Computed with equation (15-17), material data functions of strain rate

DRK_Var(i) Temperature or strain rate of the ith sampling point for Dynamic Recrystallization Kinetics

DRGS_Flg Flag for Dynamic Recrystallized Grain Size

= 1, Computed with equation (18-19), material data functions of temperature

= 2, Computed with equation (18-19), material data functions of strain rate

DRGS_Var(i) Temperature or strain rate of the ith sampling point for Dynamically Recrystallized Grain

Size

GG_Flg Flag for Grain Growth

= 1, Computed with equation (20), material data functions of temperature

= 2, Computed with equation (20), material data functions of strain rate

GG_Var(i) Temperature or strain rate of the ith sampling point for Grain Growth

TempNR Recrystallization stop temperature

NP1 – 9 Number of sampling points for corresponding material data set

a 1 – 10 (i) Material data

b 1 – 2 (i) Material data

c 1 – 8 (i) Material data

n 1 – 8 (i) Material data

m 1 – 8 (i) Material data

Q 1 – 8 (i) Material data

d (i), md (i), s (i) Material data

k d (i), k md (i), k s (i) Material data

 Inter-pass strain lost coefficient

TempNR Cut-off temperature (below which grain model is not computed)

DEFINITION

GRNDAT specifies the grain evolution data, including static, meta-dynamic, dynamic recrystallization

and grain growth for a material

REMARKS

The grain size evolution models are specified as following

Static Recrystallization Model

1) Activation Criteria

When strain rate is less than , static recrystallization occurs after deformation

(1)Kinetics

The model for recrystallization kinetics is based on the modified Avrami equation

(2)

where t 0.5 is an empirical time constant for 50% recrystallization:

(3)Grain Size

The recrystallized grain size is expressed as a function of initial grain size, strain, strain rate, and temperature

The recrystallized grain size is expressed as a function of initial grain size, strain, strain rate, and temperature

(13)Kinetics

The Avrami equation is used to describe the relation between the dynamically recrystallized fraction X

and the effective strain

(15)where 0.5 denotes the strain for 50% recrystallization:

(16)Grain Size

The recrystallized grain size is expressed as a function of initial grain size, strain, strain rate, and temperature

Retained Strain and Grain Size

When there are multiple deformation processes, strain may be reduced during the interpass period due

to recovery, the following equation is used to compute the retained strain at the beginning of the subsequent deformation

(21)The mixture law was employed to calculate the recrystallized grain size for uncompleted recrystallization,

d 0 Initial grain size

d rex Recrystallized grain size

t 0.5 Time for 50% recrystallization

Z Zener Holloman parameter

HDNEST

HDNEST Obj, Type, Unit, Temph, Templ

OPERAND DESCRIPTION DEFAULT

Obj Object number NONE

Type kind of hardness estimation NONE

=0 no estimate

=1 using Jominy Curve (for quenching process)

=2 using volume fractions of each phase

=3 using only cooling time

-n – user routine n

Temph referenced high temperature

Templ referenced low temperature

DEFINITION

HDNEST specifies the hardness for a material

SYSTEM UNITS: USER DEFINED

REMARKS

HDNEST specifies the estimation method of hardness

For Type=1 (Using Jominy Curve), the user must specify the high and low reference temperatures under which the Jominy curve is valid The hardness is estimated using both

the cooling time and Jominy data The data is specified in the keywords HDNTIM and JOMINY

For Type=2, the weighted average of hardness of each phase (defined in HDNPHA) is

used to estimate the hardness

He = hardness of element

Vfi= volume fraction of phase in element

Hi= Hardness of phase

For Type=3 only the cooling versus distance curve is used for the estimation of hardness General Guidelines for selecting the hardness estimation method

If the user does not want to spend the time with entering vast amounts of data it is

recommended that the user selects estimation method type 2, volume fraction The disadvantage in using this method is that it may not be as accurate as using the Jominy estimation

Note: The cooling time is only valid in a given temperature range

Applicable Simulation Modules: Microstructure

Applicable Simulation Modes: Transformation

Applicable Object Types: ALL except rigid

HDNOBJ

DEFINITION

HDNOBJ stores the hardness value and cooling time for each element The manner on which values

are used for the estimation of hardness depends on the keyword HDNEST If hardness calculations

are not performed, both the hardness values and cooling times will be written as zero values

REMARKS

Applicable Simulation Modules: Microstructure

Applicable Simulation Modes: Transformation

Applicable Object Types: ALL