Although　the　potential　contact　force　proposed　by　Munjiza　overcomes　the　difficulties　inherent　in　the　traditional　discrete　element　methods,　the　physical　meaning　of　the　potential　is　not　clear　and　the　contact　force　derived　from　the　original　potential　function　is　strongly　dependent　on　the　mesh　configuration.　In　this　study,　we　redefine　a　potential　function　and　propose　a　new　contact　force　calculation　method　based　on　a　unified　standard.　Moreover,　the　new　potential　function　retains　all　the　advantages　of　the　original　potential　function　but　has　less　mesh　dependency.　Copyright　(C)　2016　John　Wiley　&　Sons,　Ltd.