final_tj-sampe-poster-rev_cx
TRANSCRIPT
• 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*