Hello, everyone,

These days, I am studying the Fortran. I want to know which complier is good for fortran. My computer system is 64 bit Win7 system. I want to use fortran to do some numerical calculation about the structure dynamics.

Thank you for your sugestion.

Hi, please help me on the simulation on the orthotropic material in ABAQUS. I have the parameters for the material density=1584;
Ex=127.9e9
Ey=10.27e9
muxy=0.22;
muyx=0.0177;
Gxy=7.312e9;How can i use the orthotropic or engineering constant to simulate the material. I want to calculate frequency for orthotropic plates.

Thank you for your concern.

When use matlab or mathematica integrate this y = int(cos(m*pi*x/a)*cos(n*pi*x/a)/(x+a0)^2,x,0,a); (m,n=0,1,2,3,4,5...)

There is some explicit integral. I try to solve this problem. But the result is complex.

Is there some effective way to solve this problem.  

Thanks! 

Dear All,
These days I am do some research on vibration of circular plates (out-of-plane and in-plane). In the reference, the displacement in radial direction can be expressed with Bessel polynomial. I want to use the Rayleigh-Ritz method to solve these problems. The strain energy and kinetic energy can obtain with integral. If there is the bessel function, how to calculate the integral. Also I want to consider some spring in the boundary to change the boundary conditions.
Or there are some other method to do? Express the displacement in the radial direction with trigonometric function?
Hope all can give me some advice on it.
Thanks.

Hi, everyone, Is there some methd for the coordinate transform from circle to square.

Thank you for your suggestion.

Ask help for one paper in the inter noise conference 2011

Title: Application of virtual mode synthesis method for ship compartment impact noise

Page: 147-156

Thank you very much.

if M is your mass matrix and K is the stiffness matrix, use
[phi w2]=eig(K,M);
  phi contains the eigenvectors (each column is a modeshape)
 w2 is a diagonal matrix, each diagonal entry contains wn(i)^2
 (i.e. the i'th natural frequency squared).

Then how to draw the mode shape with eigenvectors?

 Thank you.