Integration of Design and Analysis Models

Transcription

1 Integration of Design and Analysis Models Matthijs Sypkens Smit Delft University of Technology An introduction to a new NWO-sponsored project

2 Outline of the Presentation 1 Introduction 2 Meshing 3 Analysis Models 4 Protoyping

3 What are we talking about? Key terms in product development CAD, CAM & CAE Computer-aided engineering aka analysis: Stress and strain Heat propagation Injection molding... and more

4 What are we talking about? Key terms in product development CAD, CAM & CAE Computer-aided engineering aka analysis: Stress and strain Heat propagation Injection molding... and more

5 What are we talking about? Key terms in product development CAD, CAM & CAE Computer-aided engineering aka analysis: Stress and strain Heat propagation Injection molding... and more

6 What are we talking about? Key terms in product development CAD, CAM & CAE Computer-aided engineering aka analysis: Stress and strain Heat propagation Injection molding... and more

7 A closer look at how CAD and CAE relate The CAD-CAE product development cycle: CAD model Design done Results Geometry repair & model idealization FE Analysis Mesh generation Not fully optimized: No uniform data model Human intervention necessary Computational expensive steps fully repeated

8 How can the development cycle be shortened? Three ways to improve: 1 Increased modeling efficiency 2 Automation of human-performed tasks 3 Increased computational efficiency Condition: High level of integration between steps Feature modeling has offered improvements, but potential benefits in CAE have not really been investigated.

9 Closer integration with CAE Observation: The CAE step should be regarded as an aspect of design not as a separate process In such an approach the CAE subprocess would: Have access to higher level data than pure geometric Maintain consistency between models: Through the cycle: design analysis mesh In parallel: multiple analysis models Have analysis results coupled to the design process The research project studies the realization of these goals.

10 Meshing research questions Standard meshing practice: Current BRep as only geometry source Mesh-sizing explicitly input by engineer Research: Have features control the meshing process Maintain the mesh using knowledge from parametric feature modification

11 Using features for meshing Key idea Allow engineer to interact in natural (high level) terms with data Challenges: Define analysis features. Related concepts: Boundary conditions for analysis Maximum stress/strain specification Mesh-size requirement Automatic feature conversion Handle overlapping features

12 Reusing the mesh: local remeshing Challenges: Maintain link between elements and (feature)geometry NB: Elements are not restricted to feature boundaries! Determine which elements remain the same, move, change shape, disappear and where elements need to be added Ex.

13 Reusing the mesh: local remeshing (2) More challenges: Maintain quality of whole mesh: Boundary sensitive Conforming to mesh-sizing requirements High-quality elements Use less time than a complete remesh Basic idea to work from: Use a cellular model as basis for tracking reparametrization A cellular model: slot 1, slot 2 slot 1 slot 2 slot 2 slot 1

14 Analysis models Reminder: Analysis models are abstractions from the geometric model often (partially) reduced in dimension Common practice: Analysis models are derived from a design model or made from scratch No coupling Each analysis model is treated separate from others

15 Analysis models and multiple-view design Research goal: Integration of analysis models into the multiple-view feature model: Propagation between design and analysis models Propagation between multiple analysis models Challenges: Choose abstractions automatically Keep models consistent: Reduced feature sets Dimensionally reduced features Define a useful modeling approach

16 Engineering challenges Spiff and open source meshing tools can be used as basis. Spiff: Large and complex code The cellular model might not be sufficient to support analysis models Existing meshing tools: Quality elements require non-trivial code Separate tools for surface and volume meshing Limited to planar input or geometry kernels other than ACIS Not designed with local remeshing in mind

17 Engineering challenges Spiff and open source meshing tools can be used as basis. Spiff: Large and complex code The cellular model might not be sufficient to support analysis models Existing meshing tools: Quality elements require non-trivial code Separate tools for surface and volume meshing Limited to planar input or geometry kernels other than ACIS The End Not designed with local remeshing in mind

18 Elements are not restricted to feature boundaries back