Finite Element Mesh Symmetric Constraint Modification

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Solution Overview

Problem

Existing CAD and CAE systems lack efficient methods for modifying finite element mesh representations of 3D models to maintain symmetrical properties, especially when dealing with asymmetrical objects or subparts, which limits ergonomic design and simulation accuracy.

Innovation Solution

The method involves defining a symmetric constraint on a finite element mesh, identifying corresponding elements, and performing symmetric manipulations, such as vertex translations or edge modifications, using a local symmetric plane to maintain symmetry across the mesh, allowing for geometric differences and movement without breaking the symmetry constraint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If symmetrical modification is applied to the entire finite element mesh, then symmetry is maintained across the model, but flexibility to modify only specific subparts is reduced

Engineering Contradiction:
Improveflexibility to modify subpartsVSAvoidcomplexity of symmetry constraint management
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the finite element mesh into multiple zones with different symmetry constraint levels. Individual zones can be independently modified while maintaining symmetry only where required, allowing flexible subpart modification without being constrained by global symmetry requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local symmetry constraints where different regions of the mesh can have different symmetry properties. This allows specific subparts to be modified asymmetrically while other regions maintain symmetrical modification, providing localized control over symmetry enforcement.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the finite element mesh is modified to represent geometric differences, then design accuracy is improved, but maintaining symmetry constraints becomes more difficult

Engineering Contradiction:
Improvedesign accuracyVSAvoidease of maintaining symmetry
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent implements a dynamic symmetry constraint system that automatically adapts when geometric modifications are detected. The system identifies modified elements and dynamically adjusts symmetry constraints to accommodate geometric differences while maintaining symmetry where appropriate, making it easier to maintain symmetry during iterative design processes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs a feedback mechanism where the system continuously monitors the finite element mesh for modifications and automatically responds by adjusting symmetry constraints. When geometric differences are introduced, the system provides feedback to maintain symmetry constraints, reducing the manual effort required to preserve symmetry.

Inventive Principle:
Principle #23Feedback

3Reliability

If the finite element mesh is refined or moved, then simulation accuracy and design flexibility are improved, but symmetry constraints may be broken

Engineering Contradiction:
Improvesimulation accuracyVSAvoidstability of symmetry constraint
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary actions by pre-defining symmetry constraints and identifying corresponding elements before mesh refinement or movement operations. This allows the system to proactively maintain symmetry by preparing the constraint structure in advance, preventing symmetry breaking during subsequent mesh operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a self-service mechanism where the finite element mesh automatically maintains its own symmetry constraints during refinement and movement operations. The system independently identifies and corrects potential symmetry violations without requiring external intervention, ensuring both simulation accuracy and constraint stability.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3182378B1Modification of a constrained asymmetrical subdivision mesh
Publication Date: 2021.08.11 DASSAULT SYSTEMES SA
  • EP3182378B1 patent drawingFigure 1
  • EP3182378B1 patent drawingFigure 2
  • EP3182378B1 patent drawingFigure 3

AI summary

Embodiments provide methods and systems for modifying a finite element mesh representation of a three-dimensional model. A method according to an embodiment defines a symmetric constraint of a finite element mesh where the finite element mesh is a representation of a subject 3D model and the symmetric constraint comprises two asymmetric zones of the finite element mesh to be modified symmetrically. Next, corresponding finite elements between the two asymmetric zones are identified and a manipulation to at least one of the identified corresponding finite elements is performed. In response, the manipulation is performed symmetrically on a second or more of the identified corresponding finite elements where the second or more finite elements were identified as corresponding to the at least one finite element. In such an embodiment, performing the manipulation symmetrically results in the two asymmetric zones being modified symmetrically and represents a symmetrical modification in the subject 3D model.