research at welding equipment and engineering department speaker: andrey batranin, phd. student...

Research at Welding Equipment and Engineering Department

Speaker: Andrey Batranin, PhD. Student

Tomsk Polytechnic University

Non-destructive Testing Institute

http://svarka.tpu.ru

Speaker: Andrey Batranin email: [email protected]

Contents

• Modeling of Processing

• Our Methods to Solve the Problems

• Mathematical Definition of the Problems

• Applications of the Methods

• Conclusions

Modeling of Processing


We focus on modeling of different kinds of processing:

• Welding• Cutting• Surface treatment• Hardening• Dynamic (shock) fracture


Our Methods to Solve the Problems

Primarily we use Finite Difference Method.

Sometimes we use Variation-Difference Method and

Smoothed Particle Hydrodynamics (SPH) Method

Also we use state equations for complex materialssuch as mixtures and alloys.


Mathematical Definition of the Problem

С(Т) – heat capacity;(Т) – density; Т – temperature;(Т) – heat conductivity;Q(x,y,z,t) – heat power in a point.

)1(),,,()()()()( tzyxQTgradTdivt

TТTC

To solve problems of welding we use

Spatial Non-linear Dynamic Heat Transfer Equation



Initial and Boundary Conditions

Initial condition:

0)0,,,(

)2(),,()0,,,(

ТzyxT

zyxfzyxT

Common boundary condition:

Melting and crystallization by Stephan’s equation

)3(0

Тn

T

)4(_

1

k

kk

k

kkkk n

T

n

TVL


Surface heat sources

I – current, A;

U – voltage, V;

k – heat energy concentration coefficient, 1/m2;

r – distance between a point and the center of a heat spot, m.

TIG-welding )5( exp 2kr

kIUQуд

(6) exp2

02

0

r

rk

r

kIEQуд

Electron beam treatment

Е – accelerating voltage, V;

k – beam concentration coefficient, 1/m2

r0 – beam acting radius, m.



Thermophysical properties of materials

considerably depend on temperature.


We use the Conservation Laws of Mass, Energy and Linear Momentum in partial differential equations.

Additionally are used state equations for wide range of temperature and component concentration.

Thus the models takes into account the following items:

• Non-linearity of physical properties (thermal dependences)• Spatial geometry of a piece (3D form)• Inhomogeneity: porosity, inclusions• Phase transformations: melting, crystallization, etc.• Complexity of heating: moving sources, preheating, etc.



Applications: software

The “Model” Program


Problems were solved:

• Oxygen cutting• TIG-welding• Impulse TIG-welding

The “Meza” Program



The “Meza-cutting” Program



Problems were solved:

• Oxygen cutting• Electron beam treatment

of titanium alloys


Computing of stress and deformed states in welds


Problem was solved:

• Thermal-deformative process during and after welding in a weld joint

t = 0.1 sec t = 0.2 sec



Problem was solved:

• Plastic deformation in HAZ after welding

Computing of stress and deformed states in welds

The “Virtual Workspace” Program (MATLAB)



Trying to use:

• A modern software• HPC possibilities • Collaboration

Applications: developments


Furthermore the following researches are carrying out at our department:

• Stress computation of gradient materials• Composition optimizing of coats• Impulse control of arc welding• Resistance welding of thin-walled pieces

Conclusions

We model different technological processes:

• To determine behaviour of materials during and after a process

• To choose the optimal treatment among possible ones

• To obtain a material or surface or joint with properties we need

• To create a base for automation of processing


Thank you!

http://svarka.tpu.ru

research at welding equipment and engineering department speaker: andrey batranin, phd. student...

Documents

andrey batranin email

heat spot

heat sourcesi current

t heat power

1m2r0 beam

state equations

weldingelectron beam

deformed states