Location effects on bend-twist coupling modes characteristic of the laminate plates

In this paper, the effects of coupling location on the properties of bending-twist modes are proposed. The static test and modal analysis of the composite plates are investigated. Initial coupling effects are first obtained from the static test of the plates. The frequencies, nodal lines, and the mode shapes are then studied experimentally and numerically. A new method is proposed to quantitatively describe the bending-twist coupling performance of laminates using modal assurance criterion. The results show that the coupling location in the middle coupled plates show good coupling effects at lower order vibrations. These results also show that the effect of coupling stiffness. The conclusions can be considered as a reference to analyze the coupling phenomenon of large composite wind turbine blades.

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Static test of the embedded fiber Bragg gratings composite wind turbine blades

10.1117/12.880617 ◽

2011 ◽

Cited By ~ 1

Author(s):

Zhichun Zhang ◽

Zhong Huang ◽

Yanjiu Liu ◽

Jinsong Leng

Keyword(s):

Wind Turbine ◽

Turbine Blades ◽

Fiber Bragg Gratings ◽

Bragg Gratings ◽

Wind Turbine Blades ◽

Static Test

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Modal Analysis of Wind Turbine Blades Based on ANSYS Modeling

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.790.655 ◽

2013 ◽

Vol 790 ◽

pp. 655-658

Author(s):

Chi Chen ◽

Min Wang ◽

Long Zou

Keyword(s):

Wind Turbine ◽

Modal Analysis ◽

Detailed Analysis ◽

Dynamic Characteristics ◽

Natural Vibration ◽

Turbine Blades ◽

Mode Shapes ◽

Wind Turbine Blades ◽

Horizontal Axis Wind Turbine ◽

Basic Parameters

The modal analysis is an approximate method to study the dynamic characteristics of the structure, the modal is the natural vibration characteristics of the structure, each modal has a specific natural frequency, damping ratios and mode shapes. This thesis will take 1.2MW horizontal axis wind turbine blade for example, and use parametric language APDL of ANSYS for directly modeling, then set the basic parameters of the material, mesh and discuss modal analysis, lastly conduct a detailed analysis of the results.

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Acoustic Emission Monitoring of Small Wind Turbine Blades

ASME 2002 Wind Energy Symposium ◽

10.1115/wind2002-63 ◽

2002 ◽

Cited By ~ 3

Author(s):

P. A. Joosse ◽

M. J. Blanch ◽

A. G. Dutton ◽

D. A. Kouroussis ◽

T. P. Philippidis ◽

...

Keyword(s):

Acoustic Emission ◽

Wind Turbine ◽

Fibre Composite ◽

Turbine Blades ◽

Wind Turbine Blades ◽

Static Test ◽

Damage Propagation ◽

Test Methodology ◽

Certification Procedure ◽

Damage Processes

Wind turbine blade certification tests, comprising a static test, a fatigue test, and finally a residual strength test, often involve sudden audible cracking sounds from somewhere within the blade, without the operators being able to locate the noise source, or to determine whether damage (minor or major) has occurred. A current EC-funded research project is looking at the possibility of using acoustic emission (AE) monitoring during testing of fibre composite blades to detect such events and assess the blade condition. AE can both locate and characterise damage processes in blades, starting with non-audible signals occurring due to damage propagation at relatively low loads. The test methodology is discussed in the context of the blade certification procedure and results are presented from a series of static and fatigue blade tests to failure in the laboratory. Inferences are drawn about small differences in the manufacture of the nominally identical blades and conclusions are presented for the application of the methodology.

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GA-BP Neural Network-Based Strain Prediction in Full-Scale Static Testing of Wind Turbine Blades

Energies ◽

10.3390/en12061026 ◽

2019 ◽

Vol 12 (6) ◽

pp. 1026 ◽

Cited By ~ 8

Author(s):

Zheng Liu ◽

Xin Liu ◽

Kan Wang ◽

Zhongwei Liang ◽

José A.F.O. Correia ◽

...

Keyword(s):

Wind Turbine ◽

Turbine Blades ◽

Back Propagation ◽

Health Assessment ◽

Prediction Method ◽

Full Scale ◽

Wind Turbine Blades ◽

Static Test ◽

Static Testing ◽

Input Variables

This paper proposes a strain prediction method for wind turbine blades using genetic algorithm back propagation neural networks (GA-BPNNs) with applied loads, loading positions, and displacement as inputs, and the study can be used to provide more data for the wind turbine blades’ health assessment and life prediction. Among all parameters to be tested in full-scale static testing of wind turbine blades, strain is very important. The correlation between the blade strain and the applied loads, loading position, displacement, etc., is non-linear, and the number of input variables is too much, thus the calculation and prediction of the blade strain are very complex and difficult. Moreover, the number of measuring points on the blade is limited, so the full-scale blade static test cannot usually provide enough data and information for the improvement of the blade design. As a result of these concerns, this paper studies strain prediction methods for full-scale blade static testing by introducing GA-BPNN. The accuracy and usability of the GA-BPNN prediction model was verified by the comparison with BPNN model and the FEA results. The results show that BPNN can be effectively used to predict the strain of unmeasured points of wind turbine blades.

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Analysis of Modal Parameters Using a Statistical Approach for Condition Monitoring of the Wind Turbine Blade

Applied Sciences ◽

10.3390/app10175878 ◽

2020 ◽

Vol 10 (17) ◽

pp. 5878 ◽

Cited By ~ 2

Author(s):

Lukasz Dolinski ◽

Marek Krawczuk

Keyword(s):

Wind Turbine ◽

Turbine Blades ◽

Primary Objective ◽

Rotor Blades ◽

Mode Shapes ◽

Wind Turbine Blades ◽

Horizontal Axis Wind Turbine ◽

Bending Vibrations ◽

Low Frequencies ◽

Composite Blade

The primary objective of the presented paper is the numerical and experimental investigation related to developing a useful diagnostic method, which can be used for determining the site and size of damage in laminated shells of wind turbine blades. The described detection technique is based on the analysis of low frequencies bending vibrations mode shapes of rotor blades. The authors used the commonly applied statistics methods that have been adapted to detect edges of damage, including the normalized determination coefficient fit, which is a measure of the absolute fit between two curves. The research was conducted for a scaled-down blade of a three-bladed horizontal-axis wind turbine with 36 m diameter rotor. The study was divided into two parts. The first stage included numerical calculations using the finite element method, which were supplemented in the second stage by measurements under laboratory conditions of the specially manufactured composite blade. The forms of natural vibrations for intact and damaged blade were determined using Laser Doppler Scanning Vibrometry. The results of the presented research confirm the effectiveness of the modal analysis combined with statistic calculation in damage detection. The method points out the location of relatively small damage.

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Experimental and Numerical Comparison of Impact Behavior between Thermoplastic and Thermoset Composite for Wind Turbine Blades

Materials ◽

10.3390/ma14216377 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6377

Author(s):

Thiago Henrique Lara Pinto ◽

Waseem Gul ◽

Libardo Andrés González Torres ◽

Carlos Alberto Cimini ◽

Sung Kyu Ha

Keyword(s):

Wind Turbine ◽

Structural Integrity ◽

Turbine Blades ◽

Composite Plates ◽

Low Velocity Impact ◽

Impact Behavior ◽

Numerical Comparison ◽

Wind Turbine Blades ◽

Hybrid Fibers ◽

Thermoset Resin

Damage generated due to low velocity impact in composite plates was evaluated focusing on the design and structural integrity of wind turbine blades. Impact properties of composite plates manufactured with thermoplastic and thermoset resins for different energy levels were measured and compared. Specimens were fabricated using VARTM (vacuum assisted resin transfer molding), using both matrix systems in conjunction with carbon, glass and carbon/glass hybrid fibers in the NCF (non-crimp fabric) architecture. Resin systems used were ELIUM 188O (thermoplastic) from Arkema Co., Ltd. and a standard epoxy reference, EPR-L20 from Hexion Co., Ltd. (thermoset). Auxiliary numerical finite element analyses were performed to better understand the tests physics. These models were then compared with the experimental results to verify their predictive capacity, given the intrinsic limitations due to their simplicity. Based in the presented results, it is possible to observe that ELIUM is capable to replace a conventional thermoset matrix. The thermoplastic panels presented similar results compared to its thermoset counterparts, with even a trend of less impact damage. Additionally, for both thermoplastic and thermoset resin systems, glass layups showed the lowest levels of damage while carbon panels presented the highest damage levels. Hybrid laminates can be applied as a compromise solution.

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