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Mathijs Peeters and Wim Van Paepegem
OptiWind WP4 blades: Detailed structural simulations of wind turbine blades: a way to improve our
understanding
Presentation outline
Mathijs Peeters and Wim Van Paepegem
In-house BladeMesher tool
Motivation and purpose
Comparison with other tools
Industrial relevance
Ongoing investigations
overview
BladeMesher motivation: industry assumes a structured layout
Mathijs Peeters and Wim Van Paepegem
Blade design • Fast tools • Many iterations • Design by standards (GL, IEC)
Final design phase • Full blade FEM • Eigen frequencies • Deflection • Buckling • IFF • FF
very high preprocessing time
Assumption: layout is structured
Drawbacks: • Approximations • Lack of flexibility
BladeMesher purpose: creating high fidelity blade models by allowing an unstructured layout
Airfoil stations B-spline/thickness interpol loft
Key locations - extrusion Mesh
Element material oriënt Complete FEM
Element sets
Mathijs Peeters and Wim Van Paepegem
Assumption: layout is UNstructured
Material layers added between key-lines Not on specific panels
Mathijs Peeters and Wim Van Paepegem
Elements : linear Shell elements
- Top – mid- bottom Solid-shell (AKA continuum shell) elements
- Transverse shear and bending -> multi elements in thickness (skin-core-skin) - Limitation: difference in normal at the nodes - refined mesh at LE
Solid elements
- layered solid elements are not possible (only brick available) - regular solid formulation possible (homogenize material in the element) - Limitation: aspect ratio
BladeMesher features: possible output requests
Mathijs Peeters and Wim Van Paepegem
Other tools make assumptions on the blade layout Other tools are not equipped to find key locations, are not stand alone but rely on specific preprocessors
NuMAD BMT
Contact with industry: Gamesa, LM Wind Power, DNV GL, ORE-catapult, CTC, Suzlon, Bladena
BladeMesher: comparison with other tools
BladeMesher: comparison with other tools
Mathijs Peeters and Wim Van Paepegem
BladeMesher: trailing edge modelling
Transition from circular root to airfoil
Trailing edge offset vectors
Different faces for adhesive
smooth transition from root to tip
BladeMesher: comparison with other tools
Mathijs Peeters and Wim Van Paepegem
BladeMesher: core chamfering
Sectio
keylines
Interpolation of the material thickness • Along key-lines • Between key-positions Chamfering in both chord and span-wise direction
BladeMesher features: support for/from external tools
Mathijs Peeters and Wim Van Paepegem
Export tools: To Abaqus CAE • Generates script that makes full shell model To Gmsh • Generates geo-file for the adhesive bonds • Generates geo-file that makes blade shell mesh
Export function Abaqus/CAE
Export shell mesh Gmsh
Export adhesive bonds Gmsh
BladeMesher validation: simulation of certification tests for actual blade
Already 3 actual blades modeled
Validation ? Static certification tests for actual blade (4 different load cases)
Mathijs Peeters and Wim Van Paepegem
Positive edge-wise
Positive flat-wise Negative edge-wise
Negative flat-wise
Mathijs Peeters and Wim Van Paepegem
BladeMesher: continuum modelling investigations
TE-adhesive
Shear webs
Adhesive between shells and webs
• Influence of chamfers on buckling • Influence of a detailed TE
Mathijs Peeters and Wim Van Paepegem
WP4: Blades
[email protected] [email protected]
Ghent University - Mechanics of Materials and Structures