What is the types of non conservative loads? distributed loads, concentrated loads, concentrated moments. what is the effect of non conservative load in solving finite element problems?
Should the stiffness matrix be symmetric for conservative loads and non-symmetric for non-conservative ones in nonlinear analysis?
The forces which purely depends of position are always conservative. Following forces are always non-conservative and can never be conservative:
- force depend on infinitesimally small displacement (hysteretic damping),
- velocity dependent forces (fluid/viscous damping)
- force depends explicitly on time (time dependent excitation force)
One can add any other category of forces in the above list.
It doesn't make any difference regarding the symmetry of stiffness matrix !
If I understand the question correctly, I would say any force that deals with energy dissipation is non-conservative. From high school physics, friction, and from mechanical vibrations, viscous damping, are two examples of non-conservative forces, because they dissipate energy over time and cause the moving object to come to rest. On the other hand, forces that deal with potential and kinetic energies only are conservative. That is because the summation of these energies remain constant (total energy is conserved) over time. I hope I understood the question correctly and that the answer helps!
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