An Improved Discontinuous Deformation Analysis to Solve Numerical Creep Problem in Shear Direction

Discontinuous deformation analysis (DDA) has been widely accepted recently for both static and dynamic problems. When studying block sliding cases, an unphysical phenomenon numerical creep (an additional small and finite sliding displacement in each step) yet may be observed. The accumulated creep displacement brings error to the stability and runout distance analysis. Therefore, a modification for DDA is proposed to overcome this numerical creep. The contact evolving in a sliding block case is first investigated and the cause to the numerical creep is deliberately illustrated. Then a modified open-close iteration (OCI) process is proposed to avoid such unphysical phenomenon, in which a new shear force evaluation method is introduced for the locked contacts that transformed from sliding state. Subsequently, the improved DDA with the modified OCI is checked by several block sliding examples under gravity and time-dependent dynamic forces. The comparing results suggest that the simulating accuracy of DDA is significantly improved.

Automated summary

Discontinuous Deformation Analysis (DDA) has been widely used for static and dynamic problems. In this study, a modified iterative process called open-close iteration (OCI) is proposed to overcome numerical creep phenomenon in block sliding cases. The reasons for the numerical creep, which is an additional sliding displacement, are investigated. The improved DDA with modified OCI is tested on several block sliding examples and shows significantly improved simulating accuracy.