Adaptive MNFFD Modeling for Topology-Consistent Thin-Walled Assemblies
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Solution Overview
Problem
Existing methods for modeling assembled thin-walled component structures face inefficiencies and inaccuracies due to complex assembly relationships, leading to difficulties in automating data exchange between CAD and CAE systems, poor geometric accuracy, and low optimization efficiency.
Innovation Solution
An adaptive geometric modeling method using multi-level NURBS-based free-form deformation (MNFFD) technique to establish implicit characterization relationships, enabling accurate geometric modeling, isogeometric analysis, and collaborative design of stiffened layouts, ensuring topological consistency and assembly relationships are maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If traditional B-Rep modeling based on NURBS is used for thin-walled structures, then geometric representation capability is improved, but modeling complexity increases due to tensor product structure limitations and requirement for boolean operations
Solution Approach 1:
The patent segments the complex thin-walled structure into multiple simpler components (plates, shells, ribs) that can be independently modeled and then assembled. This avoids the complexity of creating complex models through boolean operations while maintaining geometric accuracy through the assembly relationship definition.
Solution Approach 2:
The patent uses a hierarchical assembly structure where simpler components are nested or assembled to form complex structures. The assembly relationship is defined through embedding relationships between components, allowing complex geometries to be built from simpler nested parts rather than created monolithically.
2Extent of automation
If isogeometric analysis is applied to assembled thin-walled component structures, then integration of modeling and analysis is improved, but modeling accuracy deteriorates due to inability to create complete analytical models directly from CAD systems
Solution Approach 1:
The patent introduces an intermediary representation layer that bridges CAD modeling and CAE analysis. The assembly relationship definition serves as this intermediary, allowing data to be exchanged between CAD and CAE systems while maintaining both geometric accuracy and analysis capability. This mediator enables automated data exchange without sacrificing modeling precision.
3Productivity
If control points of NURBS curves and surfaces are used as design variables for optimization, then shape control efficiency is improved, but assembly relationship consistency deteriorates when control points are moved
Solution Approach 1:
The patent makes the assembly relationship dynamic rather than static. The embedding relationships between components are defined in a way that allows them to adapt when control points are moved. This dynamic definition ensures that assembly relationships are maintained automatically during optimization, eliminating the need for manual adjustment while preserving shape control efficiency.
4Manufacturing precision
If a large number of NURBS patches and trimming curves are used to generate complex models, then geometric accuracy is improved, but computational efficiency deteriorates due to increased model complexity
Solution Approach 1:
The patent segments complex geometries into simpler components with fewer NURBS patches. By modeling structures as assemblies of basic components (plates, shells, ribs) rather than single complex models, the number of NURBS patches and trimming curves is significantly reduced while maintaining geometric accuracy through proper assembly relationship definition.
Data Source
AI summary
An adaptive geometric modeling method for assembled thin-walled component structures oriented to integration of modeling, analysis and optimization, includes firstly, using a multi-level NURBS-based free-form deformation (MNFFD) technique to realize accurate geometric modeling of an assembled thin-walled component structure; secondly, establishing a modeling-analysis unified model suitable for isogeometric analysis of the assembled thin-walled component structure based on an MNFFD method; finally, establishing a modeling-analysis-design unified model suitable for collaborative design of a shape and a stiffened layout of the assembled thin-walled component structure based on the MNFFD method. The present invention fundamentally solves the modeling robustness problem of gaps and overlaps between thin-walled components due to the lack of accurate topological consistency in traditional modeling methods, provides a new tool for optimization design of engineering thin-walled structures. MNFFD is used, so that the geometric dimension reduction transformation from 3D design domain to 2D design domain can be realized.