| Author | Message | ||
     Nir Pony (pony) New member Username: pony Post Number: 1 Registered: 04-2009 |
Hi all, I am trying to solve the set of coupled thermoplastic equations in 2D for a beam using version 5.1.0: {equation of motion} Dis: Mu* div(grad (Dis))+(Lambda+mu)*grad(div(Dis))+X=gama*grad(Temp)+rho*dt(dt(Dis) {Heat conduction eqation} Temp: div(grad (Temp))-1/aleph*dt(Temp)-etha*div(dt(Dis)=0 Where T is a scalar, and Dis is a 2D vector (x,y) IC: Temp=0 Dis=(0,y+0.1*x^2) dt(dis)=(0,0) The first approach was to break the equations along x and y. when I run it I got an error “memory protection fault”. The solution did not converge (the number of unknown). The second approached was to define Dis as a vector variable “dis = VECTOR (disx, disy) I got an error “illegal item encountered in input”. I get the same error when I run the example 'Vector Variables'(http://www.flexpde.com/help/index.html?vector_variables2.html) What will be the optimal approach to solve this problem? Why I get the error when using the vector example? How can I define initial condition (displacement) for a vector? Pleas guide me how to address this problem. Thank you, pony | ||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1243 Registered: 06-2003 |
1. VECTOR variables are a capability of FlexPDE version 6, and are not supported in version 5. You will need to declare each component as a separate variable and provide a scalar equation for each. The HELP system we show on our website is for version 6 (the current shipping version). For version 5 Help, see the Help system installed on your computer by the version 5 installation. 2. FlexPDE will not accept second derivatives in time. You will need to declare an additional variable for the first time derivatives. See "Samples | Time_Dependent | Stress | Vibrate.pde" for a similar use of second-order time derivatives. |