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Hot Forming Introduction

2014.6.16

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Thermal thick shells for the tools (TSHELL=1)

Thermal gravity loading simulation

Thermal press hardening simulation

Default friction coefficient for hot forming (0.46)

Initial temperatures for both blanks and tools

Support of *DEFINE_TABLE_3D for *MAT_106/*MAT_244

Thermal time step for hot forming

New features

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Basic unit system

All the units will be converted to basic unit [ton, mm , s, N] in the input deck.

Unit in the GUI

Commonly used unit is provided in the GUI, user does not need to convertthem to the basic unit system manually in the hot forming setup.

Unit system

!"## $%&'() *+,% -./0% 1/%##2/% 3./4 ./ 6&%/'7 8%+(7 69"#:0

,.;292#

!"# $$ % & '() & $$ !"#+$$,- '()

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Hot forming process

./)01!2 3")41#5 6"! 7"/$1#5 (/8%% 9)/48#1#5

Full processes of hot forming in eta/Dynaform 5.9.2

Thestagesofgravity loading andpress hardening areoptional.

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Thermal thick shells for the tools

Thermal thick shells

*CONTROL_SHELLTSHELL=1

*CONTROL_CONTACTITHOFF=1

The heat transfer from blank to the tools is proportional to the temperaturegradient of the contact partners.

The thermal thick shells give us higher accuracy for longer contact times.This is necessary for the gravity phase and slow tool velocity.

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Thermal thick shells for the tools

Thermal thick shells

The artificial thickness can be calculated from the thermal effusivity

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Thermal gravity loading simulation

Since the blank material is very soft at high temperatures, the bending

of the blank during the insertion might be significant. This could affect

the initial blank position before the press hardening process.

The material properties change significantly with the temperature.

During the insertion of the hot blank into the press, some areas of theblank get in contact with the tools, some do not. In those areas where

contact occurs, the temperature of the blank decreases significantly dueto the cooling of the tools. Thus, the initial temperature distribution in the

blank before the forming stage is NOT uniform.

Thermal gravity loading

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FrictionSince there is no lubricant in hot forming, the friction is very high, the

default friction coefficient is 0.46. The user can change this if necessary.

Thermal friction

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Supports *DEFINE_TABLE_3D for stress/strain

Support of *DEFINE_TABLE_3D

Temperature

Strain rate

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Thermal time stepThermal time step is higher than the mechanical time step with dynamic

explicit time integration:

Thermal time step

TMAX = !"#$$% '(%$)*#+,

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Hot Formingis a separate module.

GUI of hot forming

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The tools of gravity/hardening arereferred to as the tools of forming.

GUI of hot forming

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Blank material definition: Structural

Thermal

Blank sheet material definition

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Select the material type anddefine the parameters of the

material.

Structural material

MAT106*MAT_ELASTIC_VISCOPLASTIC_THERMAL

MAT244*MAT_UHS_STEEL

Thermal material

1. *MAT_THERMAL_ISOTROPIC

2. *MAT_THERMAL_ORTHOTROPIC

3. *MAT_THERMAL_ISOTROPIC_TD

4.

*MAT_THERMAL_ORTHOTROPIC_TD5.

*MAT_THERMAL_ISOTROPIC_PHASE

_CHANGE

6. *MAT_THERMAL_ISOTROPIC_TD_LC

Blank sheet material definition

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Select the material type anddefine the parameters of the

material.

Structural material

MAT20 *MAT_RIGID

Tool structural material is definedautomatically.

Thermal material

1. *MAT_THERMAL_ISOTROPIC

2.

*MAT_THERMAL_ORTHOTROPIC

3.

*MAT_THERMAL_ISOTROPIC_TD

4. *MAT_THERMAL_ORTHOTROPIC_TD

5.

*MAT_THERMAL_ISOTROPIC_PHASE_CHANGE

6.

*MAT_THERMAL_ISOTROPIC_TD_LC

Tool material definition

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Setup the contact parameters foreach tool.

Contact parameters

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Setup the initial temperature foreach tool.

Used for all tools All tools have

the same initial temperature.

Initial temperature for tools

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The initial temperature of theblank is defined in the boundary

of the 1ststage.

The temperature information file

*.new_temp_ic.inc will be

included.

User can select Celsius(C)or

Kelvin(K) as the unit of

temperature.

Boundary condition

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User can modify the default parameters for hot forming in default config.

Configuration for hot forming