在abaqus的用戶手冊(cè)里只說了:Abaqus/Explicit offers distortion control to prevent solid elements from inverting or distorting excessively for these cases. The constraint method used in Abaqus/Explicit prevents each node on an element from punching inward toward the center of the element past a point where the element would become non-convex. Constraints are enforced by using a penalty approach, and you can control the associated distortion length ratio.并沒給出具體的公式和方案，請(qǐng)問關(guān)于這里的罰函數(shù)法避免單元畸變有相關(guān)的參考文獻(xiàn)嗎