Final_TJ-SAMPE-Poster-Rev_CX

• Non-metal materials: FRP, Foam, Resin, Wood • V-shaped notches

•Transversely shear stress-strain curve • Shear modulus, shear strength Objective

Bending-torsional load

Bending-torsional supported

National Lab of Wind Turbine Blade R&D Center, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190

• Material properties • Geometric structure • Load configuration

General Parameters

Bending/ Torsional Load

PRODUCE Local Strain Response

ANALYZE Nonlinear Deformation

Structure Design of Blades

INPROVE

CONTENT / OBJECTIVE

Law of Structure Properties

AFFECT

Patent NO.: 201410532785.7

TEST PLATFORM

• Test Sample Box Girder of wind turbine composite blade

• Support Simple support for bending loading

Torsional support for torsional loading • Load

Only one hydraulic cylinder for applied load Install a distributive beam to transfer bending load and torsional load.

Test Sample

Support

INNOVATION • Results applied more widely Suitable for various wind blades except their root and transition regions.

• More insights can be obtained The type and mechanism of nonlinear deformation. The relationship between the deformation and bending-torsional load. The effect of general parameters on structure performance.

• Simple and versatile (pure bending, pure torsion, bending+torsion )

Root region

Transition region Applicable region for test

• As size of wind turbine increases, the bend-twist coupling effect of blade is more significant. It is important to understand the bending and torsional behavior.

Structural test of wind blade box girder under bending-torsional loading is meaningful and promising.

BACKGROUND

• The shapes and materials of blade are complex, so it is difficult to establish general rules for structural property characteristics. • The Box Girder is the main load carrying element of a wind turbine blade.

Rotating inner pipe

Fixed outer pipe

Patent NO.: 201410752065.1

Patent NO.: 201410752062.8

Box girder

Root

Shear web

Trailing edge

Aft panel

Spar cap Leading Panel

Leading edge

Some new material and component testing technologies and equipment developed at IET-Wind are presented here.

• Rotor blades are one of the most critical components in wind turbine system, they are thin-walled composite structures with airfoil cross-sectional profiles. Aerodynamic and structural performance of rotor blades determines the overall performance of wind turbines. In order to improve their structural performance, the primary job is to understand the material and structural properties of blades.

• Typical construction of blades Leading panel & Aft panel: Sandwich constructions to provide aerodynamic profiles of blade cross section Spar cap: Composite laminates to carry primary bending moments Shear web: Sandwich constructions to support two spar caps and transfer shear forces

Box girder

• Transversely isotropic material • Thin-walled tubular shape

Test Sample

Ⅰ

Ⅱ

Ⅲ

Sample adhesion

Twisting force

Transversely pure shear

τ23

Approach

• Fixed the sample Clamping angle plate fixed for thin-plate sample Bonding plate fixed for thick-plate sample

Test Sample

Approach

Test Section

Sample

Strain rosette

Load

Clamping angle plate

Thin-plate Sample

Advantage • More uniform shear stress

distribution. • Reduce stress concentration. • Easy handling and assembly.

• Applied load Longitudinal Shear in test section.

• Sawtooth in blade leading edge Reduce Slippage Reduce material damage Improve strain measurement accuracy

• Multiple notch in blade trailing edge Adapt to the different dimensions of samples

Feature Rubber band

Sample

Extensometer fixture

ACKNOWLEDGEMENTS This study is partly financed by National Natural Science Foundation of China (NO.51405468) and Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

Thin-plate Sample

Clamping angle plate

Applicable Scope : Low-density porous materials

Patent NO.: 201420578940.4

Sawtooth leading edge

Notch trailing edge

Blade

TANG Jing, CHEN Xiao*

*chenxiao@iet.cn