2015 12-02-optiwind-Detailed structural simulations of wind turbine blades: a way to improve our understanding (Mathijs Peeters, UGent)

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