PARAM, CHKM0
Bulk Data Entry OptiStruct calculates the ratio of $\raisebox{1ex}{${m}_{0}$}\!\left/ \!\raisebox{1ex}{${m}_{0}^{\mathrm{log}}$}\right.$ and prints a WARNING if the frequency interval may not be fine enough for accurate Fatigue Damage calculation.
Parameter  Values  Description 

CHKM0  <YES, NO> 
Where,

Comments
 If $\raisebox{1ex}{${m}_{0}$}\!\left/ \!\raisebox{1ex}{${m}_{0}^{\mathrm{log}}$}\right.<0.95$ , a WARNING message is issued indicating that the frequency interval does not seem fine enough for calculation of accurate moments. This implies that the frequency interval may not be fine enough for accurate Fatigue Damage calculation. A way to improve this is to increase number of frequencies defined on the FREQi entries appropriately.
 If the frequency interval is fine enough, you can expect ${m}_{0}$ and ${m}_{0}^{\mathrm{log}}$ to be close to each other. If ${m}_{0}^{\mathrm{log}}$ is greater than or equal to 95% of ${m}_{0}$ , the ${m}_{0}$ value can become stable with regard to number of frequencies. If the ${m}_{0}$ value is stable, the subsequent Fatigue Damage values are also stable.