  We theoretically study the effects of isotropic dissipation in a topological
mechanical system which is an analogue of Chern insulator in mechanical
vibrational lattice. The global gauge invariance is still conserved in this
system albeit it is destroyed by the dissipation in the quantum counterpart.
The chiral edge states in this system are therefore robust against strong
dissipation. The dissipation also causes a dispersion of damping for the
eigenstates. It will modify the equation of motion of a wave packet by an extra
effective force. After taking into account the Berry curvature in the wave
vector space, the trace of a free wave packet in the real space should be
curved, feinting to break the Newton's first law.
