Well, I m working on structural health monitoring of the mechanical systems, as a part of the research, I m working on the problem called cantilever beam. As a case of, I modeled cantilever beam to my requirements. however mass and stiffness matrix of the continuous beam is obtained using ANSYS. But, the problem is I need damping matrix to be obtained without using ANSYS. can someone explain me theoretical formulation and methodology to define the damping matrix using stiffness and mass matrix?
Thanks and regards
Dheeraj
Use Rayleigh Damping.
http://www.orcina.com/SoftwareProducts/OrcaFlex/Documentation/Help/Content/html/RayleighDamping,Guidance.htm
Hi
There are many ways to compute a classical damping matrix from mass and stiffness matrices. A Rayleigh damping matrix is proportional to the mass and stiffness matrices:
C=a*M+b*K
where a and b are related to damping ratios and frequencies.
Best regards
Hi
I advice you to see these documents. You will find what you need.
Best regards
http://www.iitk.ac.in/nicee/wcee/article/14_14-0243.PDF
http://www.orcina.com/SoftwareProducts/OrcaFlex/Documentation/Help/Content/html/RayleighDamping,Guidance.htm
http://people.duke.edu/~hpgavin/cee541/ComplexModes.pdf
damping it is a physical parameters and it is depended on your model that you may adopted. in a cantilever beam if there is no external damping, there are many researches dealing with the addition of internal damping which its called structural damping.
Hi
According to Ahmed Guerine's asnwer, to find "a" and "b" coefficients you need to pre-multiply and post-multiply mode shape matrix to decouple the equation then you can solve the first two equations with two unknowns (a and b).
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