Flexural Fatigue of Unbalanced Glass-Carbon Hybrid Composites

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Kevin B. Cox ◽  
Nils-Petter Vedvik ◽  
Andreas T. Echtermeyer
Keyword(s):  
Failure Modes ◽  
Hybrid Composites ◽  
Turbine Blades ◽  
Matrix Cracking ◽  
Shear Stresses ◽  
Interlaminar Stresses ◽  
Wind Turbine Blades ◽  
Flexural Fatigue ◽  
Glass Carbon ◽  
Interlaminar Shear

Unbalanced composite layups with bend-twist coupling show potential for aeroelastic tailoring in wind turbine blades. Before these materials can be implemented, their responses to long term cyclic loading must be considered. This paper studies the fatigue characteristics of an unbalanced glass-carbon hybrid laminate with a [45glass/−45glass/24carbon/24carbon]s layup. Flexural fatigue was performed at 7 different load magnitudes up to 1 × 106 cycles to characterize the failure modes and fatigue life of the composite. Stiffness degradation occurred on the tension side due to matrix cracking and small regions of delamination on the glass plies, whereas the failure mechanism of the laminate was by delamination between the glass and carbon. S-N curves were generated from experimental results and static finite element analyses (FEA) based on interlaminar shear stresses and were compared with laminates from previous literature. It was determined that the interlaminar stresses were influenced more so by the lower stiffness of the unbalanced layup than by the induced torsional deflections: leading to the conclusion that bend-twist coupling had little influence on flexural fatigue of glass-carbon hybrid composites.

Use of composite materials and hybrid composites in wind turbine blades

2021 ◽  
Author(s):  
Sri Sai P. Reddy ◽  
Rohan. Suresh ◽  
Hanamantraygouda. M.B. ◽  
B.P. Shivakumar
Keyword(s):  
Composite Materials ◽  
Wind Turbine ◽  
Hybrid Composites ◽  
Turbine Blades ◽  
Wind Turbine Blades

scholarly journals Falling Weight Impact Damage Characterisation of Flax and Flax Basalt Vinyl Ester Hybrid Composites

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 806 ◽  
Author(s):  
Hom Nath Dhakal ◽  
Elwan Le Méner ◽  
Marc Feldner ◽  
Chulin Jiang ◽  
Zhongyi Zhang
Keyword(s):  
Vinyl Ester ◽  
Failure Modes ◽  
Hybrid Composites ◽  
Impact Damage ◽  
Matrix Cracking ◽  
Damage Mechanisms ◽  
Pull Out ◽  
Weight Impact ◽  
Falling Weight ◽  
The Impact

Understanding the damage mechanisms of composite materials requires detailed mapping of the failure behaviour using reliable techniques. This research focuses on an evaluation of the low-velocity falling weight impact damage behaviour of flax-basalt/vinyl ester (VE) hybrid composites. Incident impact energies under three different energy levels (50, 60, and 70 Joules) were employed to cause complete perforation in order to characterise different impact damage parameters, such as energy absorption characteristics, and damage modes and mechanisms. In addition, the water absorption behaviour of flax and flax basalt hybrid composites and its effects on the impact damage performance were also investigated. All the samples subjected to different incident energies were characterised using non-destructive techniques, such as scanning electron microscopy (SEM) and X-ray computed micro-tomography (πCT), to assess the damage mechanisms of studied flax/VE and flax/basalt/VE hybrid composites. The experimental results showed that the basalt hybrid system had a high impact energy and peak load compared to the flax/VE composite without hybridisation, indicating that a hybrid approach is a promising strategy for enhancing the toughness properties of natural fibre composites. The πCT and SEM images revealed that the failure modes observed for flax and flax basalt hybrid composites were a combination of matrix cracking, delamination, fibre breakage, and fibre pull out.

Investigation on Interlaminar Shear Stresses in Laminated Composite Plates under Thermal and Mechanical Loading

2014 ◽  
Vol 592-594 ◽  
pp. 451-455
Author(s):  
Nagaraj Murugesan ◽  
Vasudevan Rajamohan
Keyword(s):  
Finite Element ◽  
Thermal Environment ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Plates ◽  
Shear Stresses ◽  
Laminated Composite Plates ◽  
Interlaminar Stresses ◽  
Composite Laminated Plates ◽  
Interlaminar Shear

In this study the combined effect of thermal environment and mechanical loadings on the interlaminar shear stresses of both moderately thin and thick composite laminated plates are numerically analyzed. The finite element modeling of laminated composite plates and analysis of interlaminar stresses are performed using the commercially available software package MSC NASTRAN/PATRAN. The validity of the present finite element analysis is demonstrated by comparing the interlaminar stresses developed due to mechanical loadings derived using the present FEM with those of available literature. Various parametric studies are also performed to investigate the effect of thermal environment on interlaminar stresses generated in asymmetric cross-ply composite laminated plates of different length to thickness ratios (L/H) and boundary conditions with identical mechanical loadings. It is observed that the elevated thermal environment under identical mechanical loading lead to higher interlaminar shear stresses varying with length to depth ratio and boundary conditions in asymmetric cross-ply laminated composite plates.

scholarly journals Deformation properties of self-adapting wind turbine blades numerical approach and optimization

2019 ◽  
Vol 23 (4) ◽  
pp. 2397-2402
Author(s):  
Xiao Chen ◽  
Li Qiu ◽  
Qiang Cen
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Turbine Blades ◽  
Numerical Approach ◽  
Wind Turbine Blades ◽  
Wind Speeds ◽  
Mechanics Model ◽  
Deformation Properties ◽  
Glass Carbon ◽  
Flexible Deformation

All wind-driven generators need to be equipped with brakes to ensure operational control and safety. Many methods are available to avoid over-speed of the blower. This paper establishes a mechanics model to investigate each point on turbine blades, which are such designed that they would change shape in high winds to reduce the frontal area through adaptive and flexible deformation. In this way, high wind speeds will cause deformation of the blades and decrease of the rotational speed, as a result the turbine slows down. A numerical analysis of the fluid in the fan housing and a force analysis of the blades are performed, and numerical results are used to design the non-uniform arrangement of the hybrid glass/carbon fiber. A wind tunnel experiment is performed on the new blade design. The experimental results show that the new blade achieves an improvement in its mechanical properties and is able to adaptively adjust the torque. During the operation of the wind-driven generator, the new blade could effectively broaden the operational range of wind speeds, thereby improving the power generation when the wind speed is low. A generator without a brake stalls when the wind speed exceeds 13 m/s. After the adoption of the self-adaptive blade made up of the uniform-section complex textile material, the power set shows reduction of noise, avoidance of blade runaway, improvement of the efficiency of the power generation, decrease of cost and enhancement of blade consistency.

scholarly journals State-of-the-art models for mechanical performance of carbon-glass hybrid composites in wind turbine blades

2020 ◽  
Vol 942 ◽  
pp. 012005
Author(s):  
Yentl Swolfs ◽  
Babak Fazlali ◽  
Arsen Melnikov ◽  
Francisco Mesquita ◽  
Vincent Feyen ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Mechanical Performance ◽  
State Of The Art ◽  
Hybrid Composites ◽  
Turbine Blades ◽  
Wind Turbine Blades

scholarly journals A Global-Local Damage Assessment Methodology for Impact Damage on Offshore Wind Turbine Blades During Lifting Operations

2018 ◽  
Author(s):  
Amrit Shankar Verma ◽  
Philipp Ulrich Haselbach ◽  
Nils Petter Vedvik ◽  
Zhen Gao
Keyword(s):  
Wind Turbine ◽  
Residual Strength ◽  
Damage Assessment ◽  
Failure Modes ◽  
Impact Damage ◽  
Turbine Blades ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Assessment Methodology ◽  
Wind Turbine Blades

Lifting the latest generation offshore wind turbines using floating crane vessels is extremely challenging. This comes with an elevated risk of blades impacting the tower or surrounding structures due to excessive crane tip motions from wave induced vessel motions. The wind turbine blades are primarily made of composite materials and thus are extremely vulnerable to impact loads causing complex damages and failure modes. One of the most critical damage type for wind turbine blades is delamination because delaminations cannot always be visually detected but can cause significant strength and stiffness reductions. An explicit structural response based approach was proposed in the previous work which is used to derive response based operational limits for single blade lifting operation using floating vessels considering probability of contact/impact and damages in the blade. An assessment of such impact induced damages on the blade was mentioned which includes modelling and predicting damages in the blade for different contact scenarios representing lifting operations in different sea states along with post impact residual strength estimation. This would require an efficient damage assessment methodology which can be utilized in practice with acceptable accuracy along with a reasonable computational cost. In this work, a simplified global-local based damage assessment methodology is presented. The paper focusses on ’shell-to-solid submodelling’ based impact damage prediction along with a brief outline of ’shell-solid coupling’ based residual strength study. The paper further presents the submodelling technique for impact investigations on DTU 10 MW blade section for a case when a projectile impacts the leading edge. Intraply damage mode based on Hashin failure criteria and Puck’s action plane theory was utilized as VUMAT in Abaqus-Explicit along with surface based cohesive behavior to model the inter-laminar failure mode. Finally, the damages and failure modes in the blade including impact induced delaminations are reported.

Effect of Hybridization on Flexural Performance of Unidirectional and Bidirectional Composite Laminates under Ambient Temperature

2021 ◽  
Vol 56 ◽  
pp. 16-33
Author(s):  
Getahun Aklilu ◽  
Sarp Adali ◽  
Glen Bright
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Carbon Fibre ◽  
Composite Laminates ◽  
Hybrid Composites ◽  
Flexural Modulus ◽  
Turbine Blades ◽  
Carbon Fibres ◽  
Wind Turbine Blades ◽  
Flexural Performance

Abstract. Fibre Reinforced Plastic (FRP) materials are widely used in several key engineering applications such as ships, aircraft, wind turbine blades, helicopter blade, automobiles, and other transportation vehicles because of their mechanical properties and tailoring capabilities.Carbon and glass fibres are the most popular fibre reinforcements used for composite components. In the present study, two different stacking sequences, (0 degrees) and (0/90 degrees), are selected to study effect of fibre hybridization on flexural performance using three-point bending tests. Materials used are E-glass and T-300 carbon fibres in an epoxy matrix and the laminates were produced by resin transfer moulding methods. Fracture surfaces of composite laminates were examined using a scanning electron microscope. The results showed that the flexural strength, modulus and strain at failure of unidirectional and bidirectional composite laminates were strongly influenced by stacking sequences, fibre orientation and the hybrid ratio of the fibres. A higher flexural modulus was achieved when carbon fibres were placed on the compressive side. Hybrid specimens showed higher flexural strength and modulus by 21.08% and 145.39%, respectively, compared to the pure glass fibre reinforced laminates. On the other hand, flexural strength and modulus of hybrid specimen were less by 6.50% and 8.20%, respectively, as compared to carbon fibre reinforced specimens. Stacking sequences and hybrid ratio of glass/carbon fibre reinforced specimens were investigated with a view towards improving the mechanical properties of hybrid composites.

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