Nonlinear Newton-Raphson Iterative Method in Steel Frame Analysis

[yaw2kk]

Dear all,

I'm trying to write a Nonlinear solution for a frame using Newton Raphson Method and I think I've done everything I need to do as required by the method but my load-dispacement curve is still a straight line.

I'm using Mathcad to do this.

When I use a Simple Load Incremental Approach, i.e. by excluding the iterative process I get a good representation of Load-Deflection curve. When I try include the iterative process however, in order to get the loads to converge before moving to the next load step my Load-Deflection representation is then a straight line.

Can anyone help me please?

Further details can be provided on request.

Kind Regards,

Ken

 

[desertfox]

Hi yaw2kk

Can you post the details of your question upload your calculations that you have done so far.

desertfox

 

[JStephen]

My first thought is that if the frame itself behaves basically in a linear fashion, then your load-deflection curve would be a straight line, even if the solution method used allowed non-linear behaviour. IE, maybe you did it all right?