Is the damping matrix always diagonal when employing visco-hysteretic model to represent damping?

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Engr. Tufail

Mahdi Chehreghani No, the damping matrix is not always diagonal when employing a visco-hysteretic model to represent damping. In a visco-hysteretic model, the damping force is proportional to the velocity of the vibration, but it also depends on the history of the vibration. This means that the damping force can be different in different directions, and so the damping matrix will not be diagonal.

Natividad Garcia Troncoso

Mahdi Chehreghani No, the damping matrix is not always diagonal when employing a visco-hysteretic model to represent damping in a structural system. The damping matrix can take various forms, depending on the characteristics of the damping behaviour being modelled and the specific modelling approach being used. In a visco-hysteretic damping model, damping is often a combination of viscous (proportional) damping and hysteretic (inertial) damping. There are some damping matrices used in structural analysis like the Rayleigh damping which is a commonly used approach that combines mass-proportional damping and stiffness-proportional damping. The damping matrix (C) in Rayleigh damping takes the form: C = αM + βK.