A variety of approaches have been proposed to determine the onset of jamming (unjamming) transition for granular medium. However, these approaches all have their own limitations. In this study, the applicability of the existing approaches in identifying the jamming (unjamming) transition instant is evaluated based on the discrete element method simulations on both frictionless and frictional specimens subjected to different loading protocols which lead to isotropic jamming, shear jamming and shear unjamming. A new approach based on Hill’s criterion of failure is proposed, which defines the transition of second order work from positive to negative as the onset of jamming (unjamming) transition. The jamming (unjamming) transition instant determined from the new approach is compared with those determined from some classic approaches. It is found that the second order work-based approach not only locates the critical solid fraction in the jamming diagram consistent with other approaches, but is also able to identify the onset of jamming (unjamming) transition for loading protocols that are difficult to be assessed by the existing approaches. This more robust approach is useful for the study of jamming phenomena under a broader types of loading protocols, and can be further employed to derive the jamming diagram of real materials.

已经提出了多种方法来确定粒状介质的堵塞（未堵塞）转变的开始。但是，这些方法都有其自身的局限性。在这项研究中，基于离散元素方法模拟，对在不同加载方案下导致各向同性堵塞，剪力堵塞和剪力堵塞的无摩擦和摩擦样本进行评估，评估了现有方法在识别堵塞（未堵塞）过渡瞬间时的适用性。 。提出了一种基于希尔失败准则的新方法，该方法将二阶功从正向负转变定义为干扰（非干扰）转变的开始。将新方法确定的干扰（取消干扰）过渡瞬间与某些经典方法确定的干扰瞬间进行比较。发现基于二阶工作的方法不仅可以在干扰图中找到与其他方法一致的关键固体部分，而且还可以识别难以评估的加载协议的干扰（未干扰）转变的开始通过现有方法。这种更鲁棒的方法对于研究更广泛类型的加载协议下的堵塞现象很有用，并且可以进一步用于得出真实材料的堵塞图。