Energy dissipation of each dissipation mechanism in [erg] against filling factor φ. The solid lines show the result in the case without the normal damping and the dashed lines in the case of k_n = 0.01 and The results in the case of k_n = 10 are not plotted because they are the same as those in the case of k_n = 0.01 and indistinguishable. The dissipation mechanisms are normal damping, rolling, sliding, and twisting. The dissipation energy by sliding motion is less than 10^-9 erg.