由于钻头上的牙齿在油气井中是连续破碎岩石的，而传统破碎比功仅能评价牙齿单次加载的破岩效率，不能评价和预测牙齿二次加载及连续加载的破岩效果。基于ANSYS自定义损伤本构的二次开发，建立了试验和仿真的二次破碎比功和总破碎比功模型。选用单齿单次压入破岩工况，结合试验和理论计算验证了损伤本构模型和数值仿真方法的正确性，最后利用二次开发的损伤本构模型对单齿一次、二次和连续总的破碎比功进行了分析。结果表明，基于损伤本构的破碎比功评价模型能够准确地预测二次破碎及连续破碎的效果，且随着载荷增加破碎比功缓慢下降，与单齿一次破碎比相比，在同一处的二次破碎及连续两次破碎的破碎比功将分别减小约80%和60%。

The teeth of the bit break rock continuously when drilling in oil or gas well. However, the primitive crushing work ratio is used to evaluate single rock crushing effect, thus it is unsuitable to estimate and predict the second rock crushing and continuous breaking effects. Based on a second development of damage constitutive model in ANSYS software, the new models of crushing work ratio are developed. The applicability of the developed damage constitutive model and numerical simulation is verified by experiments and theoretical calculation under the condition of single rock crushing. Then the model is employed to analyze the single, the second and the total crushing work ratios. It is found that the evaluation model is efficient to predict the rock breaking effects of the second and total breaking by using the new crushing work ratio which decreases slowly with the increase of load. Moreover, the work ratios of the second crushing and the total crushing is reduced to approximately 80% and 60%, respectively, in comparison with the first crushing work ratio.