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Introduction
2
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Variable-kinematics shell model
- Reduce model size by
selective refinements.
- Minimal user inputs.
Goals: Methodology:
- Variable-kinematics models.
- Variable-order cohesive
segment method.
Variable-kinematics shell model: Application to delamination - - PowerPoint PPT Presentation
Variable-kinematics shell model: Application to delamination - - PowerPoint PPT Presentation
Variable-kinematics shell model: Application to delamination analysis Aewis Hii, Luiz Kawashita, Alberto Pirrera ACCIS CDT Conference 2019 2 Introduction Methodology: Variable-kinematics models. Variable-order cohesive segment
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SLIDE 3
Variable-kinematics shell model
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Variable-kinematics shell model
3
In-plane order (n) Through-thickness order (m)
Model order N,M
… … … …
Based on the Unified Formulation. Independently defined/refined in- plane and thickness kinematics.
`Tune-able’ model kinematics
SLIDE 4
Analysis-specific model kinematics
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Variable-kinematics shell model
4
Twisted composite shell with variable thickness
For iterative design analyses
Modal analysis 3D Stresses
Parametric study for model kinematics
Large deformation analysis
Variable-kinematics model
- Model settings for
iterative analyses.
- Accurate stresses for
higher-order variants.
5 × 10 elements 10 × 20 elements 20 × 30 elements
3D stress analyses Stiffness analyses
In-plane displacement field Through-thickness displacement field
. . . . . .
𝜏33 𝜏12 𝜏23 3D-FEM
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Variable-order cohesive segment method
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Variable-kinematics shell model
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No pre-defined crack path
Damaged state Elastic
2 × Nth order 2Nth order Nth order
𝐯𝑞 = 𝐯𝑢 𝜖𝐯𝑞 𝜖𝐲 ≠ 𝜖𝐯𝑢 𝜖𝐲
Features:
- Complex crackfront geometry.
- Low model size due to adaptive refinement.
- Large element size.
Oscillation-free crack initiation and ‘partial cracking’ Kinematics blending/mapping
SLIDE 6
Model size Simulation time Model size comparison
Application to delamination analysis
6
Displacement Force
Full model Adaptive model
Relaxing mesh size requirements
Regular elements Transition elements Padding elements Delamination
‘Peeling’ of a laminate with pre-crack Elements are split `on-the-fly’ Curved crack front with rectangle mesh
1st order element 3rd order element Experiment Analytical
Pure Mode I: Double Cantilever Beam
Adaptive model for complex crackfront
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Variable-kinematics shell model
Structural response
Full model Adaptive model
SLIDE 7
Acknowledgements
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Variable-kinematics shell model
7
The authors would like to acknowledge Rolls-Royce plc for their support of this research through the Composites University Technology Centre at the University of Bristol, UK
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