Recent content by dinaharchery

Maybe my question was not properly worded. I just want to know how to apply a Neumann boundary on the first derivative (e.g., U'(x) = alpha) with a second-order ODE using finite differences - e.g. U''(x) = f(x) Is this even possible? Thanks again

I am new to differential equations, any help would be great. I have a ODE of the second order u''x = e^x over the domain [1, 1] where u'(0) = 0 is a Neumann boundary on the ODE. I am trying to approximate the solution using the finite differences method, I can do Dirichlet boundaries with...

Anyone? I just need some kind of hint in the direction to go for the application of boundary corrections at each time step. I am not an engineer but am trying to learn finite element for a program. Once again, thank you.

Well, I figured out the boundary "elimination" approach to the GLOBAL stiffness matrix as well as the vector Load/Heat-Rate:smile: (I finally got a book on FEM) The book has a section on transient heat conduction using a LUMPED capacity matrix - complete with algorithm. However, there is one...

Hello all, I am trying to create a simple finite element program in C++ and have been able to build and assemble the GLOBAL stiffness matrix as well as the load vector. I want to apply the boundary conditions using the elimination approach, can anyone tell me how to do this? I am sorry for...

I have been doing some research into the unsteady state heat for finite element analysis and have run across Gaussian quadrature. Can anyone explain how this relates to a time-marching algorithm for the FE solution to a simple 2-D (x and y) heat conductivity problem:confused:? Thanks.

The steady-state code uses a preconditioned conjugate gradient solver, so the solver itself is iterative. I would like to use the explicit euler time marching algorithm but I currently do not have a lumped capacity matrix.

Any idea at all? A simple 2-D unsteady state algorithm? Thanks again

Hello all, I am not an engineer but am trying to learn finite element analysis for solid materials - in particular heat conductivity for time dependent problems in 2-D for a single material. I am interested in the explicit Euler time marching, thus I believe I need a lumped capacity matrix...

Sorry about being so vague. The media is solid and there is only one. I am planning on using C++, no lumped mass matrix. I am looking for a Finite Element approach. Mainly I was looking for information on the theory, not necessarily an exact code since I would like to learn the process behind...

Hello, I am trying to understand one-dimensional unsteady state heat conduction for a program I am writing. The program will eventually be coded for two and three dimensional structures. Can anyone provide some basic background info./tutorial to understand the governing equation and...

Mapes, Yes, that is exactly what I did. I just wanted to be sure I was correct. Again, a million thanks for all your help.

Mapes, Once again, thank you. I derived the linear equation from the original T(x, y) = x + y and got T(x, y) = -9(100 - x) + 1000. This equation gives the same results as the equation you derived but I must have arrived at it in a different fashion. Please excuse my ignorance with...

Thanks Mapes. You have been very helpful, I really appreciate it.

The results make more sense, thank you:smile:. I just seems strange that the y coordinates have no influence on the final temperature at a given node. Can you provide any links to explain this kind of equation? I am really trying to learn this stuff.