| Author | Message | ||
     Ejaz Qureshi (qureshimeq) New member Username: qureshimeq Post Number: 1 Registered: 12-2008 |
Hello Friends, I am very much worried whether FPDE can solve a coupled three dimensional thermo-mechanical Arc welding simulation with following complexities. 1. Moving guassian distributed heat source. 2. Phase transformation. 3. Addition of Filler metal. If anyone working on this type of problem, please guide me. I am new to Flex PDE. | ||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1191 Registered: 06-2003 |
We have not done exactly this problem, but it should be possible. 1. See "Samples|Time_Dependent|Heatflow|Float_zone.pde" for moving heat source and "Samples|Steady_State|Stress|Elasticity.pde" For coupled thermo-mechanical equations. 2. See "Samples|Time_Dependent|Chemistry|Melting.pde" for phase change simulation. 3. Adding material may require a moving mesh problem. See the examples in the "Samples|Moving_Mesh" folder. | ||
| Ejaz Qureshi (qureshimeq) New member Username: qureshimeq Post Number: 2 Registered: 12-2008 |
Respected Sir, As i have mentioned, i am a new user of FEM and FPDE. Can u please develop a basic model (Linear Welding in Plate with guassian distributed moving heat source) for me so that i may continue my future research. Please incorporate elasto-plastic thermo-mechanics and filler metal deposition with phase change so that it will help me in future work in Flex PDE. I hope you will help me. Regards QURESHI | ||
| Marek Nelson (mgnelson) Moderator Username: mgnelson Post Number: 96 Registered: 07-2007 |
We cannot be responsible for designing your model. FlexPDE is a versatile product that can be used in many fields of study. As such, we cannot be experts in all possible fields. Nor do we have the man power to build models for all our customers. We are happy to answer questions about how to use FlexPDE. | ||
| gcb (gcb) New member Username: gcb Post Number: 2 Registered: 12-2008 |
Hello Friends, I am a new user of FlexPDE,I have a problem about the coupled of temperature field and fluid field in weld pool.The temperature can`t to achieve the melting point.Can you solve this problem? And I want there is no fluid field where the temperature below the temperature of the melting point.How can I complete it?Can you help me? TITLE 'weld pool' { the problem identification } COORDINATES cartesian2 { coordinate system, 1D,2D,3D, etc } VARIABLES { system variables } u(threshold=0.01) v(threshold=0.01) temp(threshold=1) p(threshold=1e-8) { choose your own names } ! SELECT { method controls } DEFINITIONS { parameter definitions } ro=6900 !Density g=9.8 !Acceleration due to gravity lamuda=if (temp<=1798)then if(temp<=1768)then if(temp<=1082)then if(temp<=851)then 60.719-0.027857*temp else 78.542-0.0488*temp else 15.192+0.0097*temp else 349.99-0.1797*temp else 349.99-0.1797*1798 !Thermal conductivity miu=if (temp<=1973)then if(temp<=1873)then if(temp<=1853)then if(temp<=1823)then 1e9 else (119-0.061*temp)*1e-3 else (10.603-0.025*temp)*1e-3 else (36.236-0.0162*temp)*1e-3 else 1e-6 !Viscosity cp=if (temp<=1379)then if(temp<=1100)then if(temp<=1023)then if(temp<=973)then 513.76-0.335*temp+6.89e-4*temp^2 else -10539+11.7*temp else 11873-10.2*temp else 644 else 354.34+0.21*temp !Heat capacity av=1e-4 !Expansion coefficient ac=80 !Heat transfer coefficient os=5.67e-8 !Stefan-Boltzmann v0=2e-3 !velocity long=0.1 wide=0.01 yita=0.65 !Arc thermal efficiency op=2e-3 i=300 !Current u0=30 !voltage gama=-0.35e-3 !Temperature coefficient of surface tension oj=(1.4875+0.00123*i)*1e-3 mium=4*pi*1e-7 !Vacuum permeability r=sqrt(x-v0*t)^2 penalty = 10000*miu/wide^2 n=if(temp<=1789)then 1 else 0 source=3*yita*i*u0/(pi*op^2)*exp(-3*(r^2)/(op^2)) Fx=-mium*i^2/(4*pi^2*oj^2*r)*exp(-r^2/(2*oj^2))*(1-exp(-r^2/(2*oj^2)))*(1-y/wide )^2*x/r !Volume force in X Fy= mium*i^2/(4*pi^2*wide*r^2)*(1-exp(-r^2/(2*oj^2)))*(1-y/wide)-ro*g*av*(temp-298) !Volume force in Y INITIAL VALUES temp=298 u=0 v=0 p=0 EQUATIONS { PDE's, one for each variable } u:ro*(dt(u)+u*dx(u)+v*dy(u))=Fx-dx(p)+miu*(dxx(u)+dyy(u)) v:ro*(dt(v)+u*dx(v)+v*dy(v))=Fy-dy(p)+miu*(dxx(v)+dyy(v)) temp:ro*cp*(dt(temp)+(n-1)*u*dx(temp)+(n-1)*v*dy(temp))=lamuda*(dxx(temp)+dyy(te mp)) p: del2(p) = penalty*(dx(u)+dy(v)) !CONSTRAINTS{ Integral constraints } BOUNDARIES { The domain definition } REGION 1 { For each material region } START(0,0) { Walk the domain boundary } natural(temp) =-source/lamuda natural(u)=-gama*dx(temp)/miu value(v)=0 line TO (long,0) value(u)=0 value(v)=0 line TO (long,wide) natural(temp) =-ac*(temp-298)/lamuda value(u)=0 value(v)=0 line TO(0,wide) value(u)=0 value(v)=0 line TO CLOSE time 0 to 10 by 0.01 { if time dependent } MONITORS { show progress } for t=0 by 0.01 to endtime grid(x,y) contour(temp) contour(u) contour(v) vector(u,v) PLOTS { save result displays } for t=0 by 0.01 to endtime contour(temp) contour(u) contour(v) vector(u,v) END I hope you will help me. | ||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1198 Registered: 06-2003 |
Be sure that all the values defined by IF..THEN are continuous across the switch points. Discontinuous parameters can cause slow running and/or oscillation. The sudden timestep crash in this problem indicates a discontinuous switch in material parameters. Perhaps this would work better if you constructed a TABLE of values, rather than a cascade of IF..THEN's. |