Meshfree Simulation of Embedded Bi-Materials

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Solution Overview

Problem

Existing methods for numerically simulating structural behaviors of embedded bi-materials, such as fiber-reinforced composites, face challenges in generating matching meshes for finite element methods, especially in irregular geometries, leading to numerical instability and high computational costs.

Innovation Solution

The approach involves creating independent grid models for the base and immersed materials, determining interface nodes, and using meshfree nodes to simulate structural behaviors with two meshfree approximations, one based on the base material properties and the other on the differential properties between the immersed and base materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If matching meshes are used for FEM simulation of embedded bi-materials, then numerical stability is improved, but mesh generation complexity and user interaction increase substantially

Engineering Contradiction:
Improvenumerical stabilityVSAvoidmesh generation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The domain is segmented into two independent grid models: one for the base material and one for the immersed material. This segmentation allows each grid to be generated independently without requiring matching interfaces, thus reducing mesh generation complexity while maintaining numerical stability through the embedded formulation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an embedded formulation where the immersed material grid is embedded within the base material grid. This intermediary approach allows non-matching grids to coexist by treating the immersed material as an embedded entity, eliminating the need for conforming meshes while preserving numerical stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of time

If independent grids are used for embedded bi-materials, then mesh generation time is reduced, but interface constraint implementation becomes more difficult

Engineering Contradiction:
Improvemesh generation timeVSAvoidinterface constraint complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The embedded formulation acts as an intermediary mechanism that automatically handles interface constraints between independent grids. By formulating the immersed material as embedded within the base material, the method automatically enforces interface conditions without requiring manual constraint implementation, thus reducing both time and complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The independent grid system with embedded formulation is self-sufficient in handling interface constraints. The mathematical formulation inherently manages the interaction between grids without requiring additional user intervention or manual constraint application, making the process more efficient and less complex.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If Lagrange multipliers are used in mortar FEM, then mismatching meshes are handled, but numerical instability may occur due to violation of inf-sup condition

Engineering Contradiction:
Improvemesh mismatch handling capabilityVSAvoidnumerical stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts the problematic Lagrange multiplier formulation from the problem and replaces it with an embedded formulation. This extraction removes the source of numerical instability (inf-sup condition violations) while preserving the ability to handle mismatching meshes through the embedded grid approach.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The method uses a simpler, more robust formulation that does not rely on the complex Lagrange multiplier machinery. The embedded formulation provides a more stable and computationally efficient solution that avoids the numerical pitfalls of traditional mortar methods.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Measurement precision

If generalized FEM or extended FEM is used for embedded bi-materials, then simulation accuracy is improved, but computational cost increases significantly

Engineering Contradiction:
Improvesimulation accuracyVSAvoidcomputational cost
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent employs a computationally efficient embedded meshfree formulation that achieves accurate simulation results without the high computational costs associated with generalized FEM or extended FEM. The method uses standard meshfree shape functions with an embedded formulation, providing a cost-effective alternative that maintains accuracy.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The method changes the formulation parameters from complex enriched shape functions (used in XFEM/GFEM) to a simpler embedded meshfree formulation. This parameter change reduces computational complexity and cost while maintaining the ability to accurately simulate embedded bi-materials through the independent grid approach.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8768660B2Numerically simulating structural behaviors of embedded bi-materials using meshfree method
Publication Date: 2014.07.01 ANSYS INC
  • US8768660B2 patent drawing
  • US8768660B2 patent drawing
  • US8768660B2 patent drawing

AI summary

Methods and systems for numerically simulating structural behaviors of embedded bi-materials are disclosed. At least first and second grid models are created independently for an embedded bi-material that contains an immersed material embedded entirely within a base material. First group of meshfree nodes represents the entire domain (i.e., base plus immersed materials). Second group of meshfree nodes represents the immersed or embedded material, which includes all interface nodes and nodes located within a space bordered by the material interface. Numerical structural behaviors of the embedded bi-material are simulated using the first and second set of meshfree nodes with a meshfree method that combines two meshfree approximations. The first meshfree approximation covers the first set of meshfree nodes and is based on properties of the base material, while the second meshfree approximation covers the second set of meshfree nodes and is based on a differential between the immersed and base materials.