Implicit FEA Contact Penetration Control
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Solution Overview
Problem
Implicit finite element analysis (FEA) struggles with accurately simulating non-linear structure responses due to excessive contact penetration, leading to distorted mesh models and unrealistic simulation results, as existing penalty methods are ineffective in controlling contact forces in implicit FEA.
Innovation Solution
A method is introduced to limit contact penetration by calculating a contact penetration parameter (CPP) based on approximate nodal contact distances and no-contact nodal displacements, using three assumptions for calculations, and applying this parameter to the implicit FEA solver to find a minimum energy imbalance location, thereby restricting contact penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If penalty method is used to simulate structural contact in implicit FEA, then contact forces can be applied to maintain contact, but the FEA mesh model becomes distorted due to large fictitious compensating forces resulting from large contact penetrations
Solution Approach 1:
The patent applies preliminary action by calculating the contact penetration parameter (CPP) before the main FEA iteration process. The CPP is computed based on approximate nodal contact distances and no-contact nodal displacements from the previous iteration, and this pre-calculated parameter is then used to constrain contact penetration during the iterative solution process, preventing large fictitious forces from distorting the mesh model
Solution Approach 2:
The patent changes the parameter approach by introducing a contact penetration parameter (CPP) that is calculated as a ratio of approximate nodal contact distances to no-contact nodal displacements. This CPP parameter is then used to scale and control contact forces during the FEA iteration, transforming the uncontrolled penalty method into a controlled parameter-based contact force application that prevents mesh distortion
2Productivity
If large time step size is used in implicit FEA to reduce computational time, then simulation efficiency improves, but contact penetration between time steps increases causing simulation inaccuracies
Solution Approach 1:
The patent implements feedback by calculating the contact penetration parameter (CPP) using information from the previous iteration (approximate nodal contact distances and no-contact nodal displacements), and then using this feedback to constrain contact penetration in the current iteration. This iterative feedback mechanism allows the use of larger time steps while maintaining contact accuracy through continuous adjustment of contact forces based on penetration detection
Data Source
AI summary
Systems and methods of limiting contact penetration in numerical simulation of non-linear structure response using implicit finite element analysis are described. According to one aspect, a finite element analysis (FEA) model of a structure is defined as a number of nodes and elements based on geometry and material properties of the structure. A time-marching analysis of the FEA model is then performed. The time-marching analysis results contain a number of solutions of non-linear structure response at respective time steps. Solution at each time step requires at least one iteration to compute. Non-linear structure response is determined in the following manner: 1) determining a search direction; 2) calculating a contact penetration parameter in the search direction; and 3) finding a minimum energy imbalance location along the search direction as a solution which is further restricted by the CPP such that contact penetration of the structure is substantially limited.