An Analysis and Experimental Study of the Rotor Blade with Composite Material Fiber Reinforced Plastics

2006 ◽  
Vol 306-308 ◽  
pp. 851-856
Author(s):  
C.Y. Son ◽  
H.I. Byun ◽  
K.H. Kim ◽  
J.K. Choi ◽  
J.Y. Shin
Keyword(s):  
Wind Turbines ◽  
Rotor Blade ◽  
Large Scale ◽  
Fem Analysis ◽  
Small Scale ◽  
Fiber Reinforced ◽  
Fatigue Load ◽  
Reinforced Plastics ◽  
Bending Load ◽  
Behavior Characteristic

In these days, large-scale wind turbines are being made of the Glass Fiber Reinforced Plastic (hereinafter F.R.P). Some reinforcement stiffeners such as carbon fiber and polyamide (Kevlar) are not economical for the wind turbine. In addition, the steel or aluminum alloy, featuring heavy weight and metallic fatigue load, is not suitable for global use, except very small-scale wind turbines. In this study, we manufactured a 10kW-grade small Rotor Blade with the F. R. P featuring high stiffness and good dynamic behavior characteristic, and carried out experiments for understanding the bending behavior characteristic of the fatigue load and bending load. And, we examined the experiment results through the Finite Element Method. We compared the experiment results and FEM analysis outputs using the commercial ANSYS FEM program.

Fiber-Reinforced Plastics with Locally Adapted Stiffness for Bio-Inspired Hingeless, Deployable Architectural Systems

2017 ◽  
Vol 742 ◽  
pp. 689-696 ◽  
Author(s):  
Larissa Born ◽  
Axel Körner ◽  
Gundula Schieber ◽  
Anna S. Westermeier ◽  
Simon Poppinga ◽  
...  
Keyword(s):  
Composite Material ◽  
Role Models ◽  
Design Principles ◽  
Biological Role ◽  
Small Scale ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics

This paper presents results of the investigation of two biological role models, the shield bug (Graphosomaitalicum) and the carnivorous Waterwheel plant (Aldrovandavesiculosa). The aim was to identify biological construction and movement principles as inspiration for technical, deployable systems. The subsequent processes of abstraction and simulation of the movement and the design principles are summarized, followed by results on the mechanical investigations on various combinations of fibers and matrices with regard to taking advantage of the anisotropy of fiber-reinforced plastics (FRPs). With the results gained, it was possible to implement defined flexible bending zones in stiff composite components using one composite material, and thereby to mimic the biological role models. First small-scale demonstrators for adaptive façade shading systems – Flectofold and Flexagon – are proving the functionality.

scholarly journals Surface toughening – An industrial approach to increase the robustness of pure adhesive joints with film adhesives

2020 ◽  
Vol 234 (13) ◽  
pp. 1980-1987
Author(s):  
MJ Schollerer ◽  
J Kosmann ◽  
D Holzhüter ◽  
C Bello-Larroche ◽  
C Hühne
Keyword(s):  
Large Scale ◽  
Adhesive Bonding ◽  
Bolted Joints ◽  
Small Scale ◽  
Bonded Joints ◽  
Fiber Reinforced ◽  
Load Path ◽  
Stress Concentrations ◽  
Manufacturing Defects ◽  
Wide Range

Bonding is known for its wide range of advantages over bolted joints when joining different materials together. However, the advantages e.g. of homogeneous load distribution can quickly be lost in case of overload. For this reason, the load occurring in the adhesive is reduced by constructive measures far below the yield stress of the adhesive, which leads to a conservative joint design. And to be on the safe side, a few “chicken rivets” are then placed again. This problem is particularly well known in aviation. Highly loaded components are structurally bonded by a combination of rivets and adhesive in order to underline the advantages of structural adhesive bonding with the safety of the well-known bolted joints. Known as fail-safe design, this concept is damage tolerant and more robust against manufacturing defects through a secured double load path.  Especially when joining fiber-reinforced composites, bolts weaken the adherends of the joint and only contribute to load transfer when the brittle adhesive fails. With the help of Surface Toughening, a boltless technique for reducing stress concentrations and arresting cracks in adhesive bonded joints is available. This work describes the industrial application of this technique. Starting with coupon tests and a small scale demonstrator to ensure the compatibility with industrial manufacturing processes, such as infusion and prepreg manufacturing, a large scale demonstrator of a 2 m carbon fiber reinforced plastic (CFRP) - HTP leading edge with hybrid laminar flow control is manufactured by the industrial partner AERnnova. Verifying a simple and cost-effective application of the technology, Surface Toughening enables robust bonded joints with a minimum impact on today's process of adhesive bonding.

Detailed Analysis of the Wake Structure of a Straight-Blade H-Darrieus Wind Turbine by Means of Wind Tunnel Experiments and Computational Fluid Dynamics Simulations

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Alessandro Bianchini ◽  
Francesco Balduzzi ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari ◽  
Giacomo Persico ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Wind Turbines ◽  
Large Scale ◽  
Vertical Axis ◽  
Performance Estimation ◽  
Small Scale ◽  
Dynamics Simulations

Darrieus vertical axis wind turbines (VAWTs) have been recently identified as the most promising solution for new types of applications, such as small-scale installations in complex terrains or offshore large floating platforms. To improve their efficiencies further and make them competitive with those of conventional horizontal axis wind turbines, a more in depth understanding of the physical phenomena that govern the aerodynamics past a rotating Darrieus turbine is needed. Within this context, computational fluid dynamics (CFD) can play a fundamental role, since it represents the only model able to provide a detailed and comprehensive representation of the flow. Due to the complexity of similar simulations, however, the possibility of having reliable and detailed experimental data to be used as validation test cases is pivotal to tune the numerical tools. In this study, a two-dimensional (2D) unsteady Reynolds-averaged Navier–Stokes (U-RANS) computational model was applied to analyze the wake characteristics on the midplane of a small-size H-shaped Darrieus VAWT. The turbine was tested in a large-scale, open-jet wind tunnel, including both performance and wake measurements. Thanks to the availability of such a unique set of experimental data, systematic comparisons between simulations and experiments were carried out for analyzing the structure of the wake and correlating the main macrostructures of the flow to the local aerodynamic features of the airfoils in cycloidal motion. In general, good agreement on the turbine performance estimation was constantly appreciated.

scholarly journals Fabrication of Fiber Reinforced Plastics by Ultrasonic Welding

2018 ◽  
Vol 2 (3) ◽  
pp. 56
Author(s):  
Andreas Gomer ◽  
Wei Zou ◽  
Niels Grigat ◽  
Johannes Sackmann ◽  
Werner Schomburg
Keyword(s):  
Carbon Fiber ◽  
Large Scale ◽  
Raw Materials ◽  
Glass Fibers ◽  
Ultrasonic Welding ◽  
Scale Production ◽  
Fiber Reinforced ◽  
Cycle Times ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics

Ultrasonic fabrication of fiber reinforced plastics made from thermoplastic polymer films and carbon or glass fibers enables cycle times of a few seconds and requires investment costs of only some 10,000 €. Besides this, the raw materials can be stored at room temperature. A fiber content of 33 vol % and a tensile strength of approximately 1.2 GPa have been achieved by ultrasonic welding of nine layers of foils from polyamide, each 100 µm in thickness, and eight layers of carbon fibers, each 100 µm in thickness, in between. Besides unidirectional carbon fiber reinforced polymer composite (CFRP) samples, multi-directional CFRP plates, 116 mm, 64 mm and 1.2 mm in length, width and thickness respectively, were fabricated by processing three layers of carbon fiber canvas, each 300 µm in thickness, and eight layers of polyamide foils, each 100 µm in thickness. Furthermore, both the discontinuous and the continuous ultrasonic fabrication processes are described and the results are presented in this paper. Large-scale production still needs to be demonstrated.

scholarly journals Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions

2015 ◽  
Vol 373 (2035) ◽  
pp. 20140080 ◽  
Author(s):  
B. F. Xu ◽  
T. G. Wang ◽  
Y. Yuan ◽  
J. F. Cao
Keyword(s):  
Experimental Data ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Large Scale ◽  
Aerodynamic Performance ◽  
Small Scale ◽  
Floating Platform ◽  
Unsteady Aerodynamic ◽  
Blade Root ◽  
Platform Motions

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip.

Detailed Analysis of the Wake Structure of a Straight-Blade H-Darrieus Wind Turbine by Means of Wind Tunnel Experiments and CFD Simulations

2017 ◽  
Author(s):  
Alessandro Bianchini ◽  
Francesco Balduzzi ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari ◽  
Giacomo Persico ◽  
...  
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Wind Turbines ◽  
Large Scale ◽  
Vertical Axis ◽  
Performance Estimation ◽  
Small Scale ◽  
Horizontal Axis Wind Turbines ◽  
Floating Platforms ◽  
Physical Phenomena

Darrieus Vertical Axis Wind Turbines (VAWTs) have been recently identified as the most promising solution for new types of applications, such as small-scale installations in complex terrains or offshore large floating platforms. To improve their efficiencies further and make them competitive with those of conventional horizontal axis wind turbines, a more in depth understanding of the physical phenomena that govern the aerodynamics past a rotating Darrieus turbine is needed. Within this context, Computational Fluid Dynamics (CFD) can play a fundamental role, since it represents the only model able to provide a detailed and comprehensive representation of the flow. Due to the complexity of similar simulations, however, the possibility of having reliable and detailed experimental data to be used as validation test cases is pivotal to tune the numerical tools. In this study, a two-dimensional U-RANS computational model was applied to analyze the wake characteristics on the mid plane of a small-size H-shaped Darrieus VAWT. The turbine was tested in a large-scale, open-jet wind tunnel, including both performance and wake measurements. Thanks to the availability of such a unique set of experimental data, systematic comparisons between simulations and experiments were carried out analyzing the structure of the wake, and correlating the main macro-structures of the flow to the local aerodynamic features of the airfoils in cycloidal motion. In general, good agreement on the turbine performance estimation was constantly appreciated.

Developing a nested micromechanical model to predict the relaxation moduli of graphene nanoplatelets/carbon fiber reinforced hybrid nanocomposites

2020 ◽  
Vol 234 (3) ◽  
pp. 504-519
Author(s):  
Shan Li ◽  
Yan Cao ◽  
Junde Qi ◽  
Hongjun Liu ◽  
Rasoul Moheimani
Keyword(s):  
Carbon Fiber ◽  
Large Scale ◽  
Graphene Nanoplatelets ◽  
Hybrid Nanocomposites ◽  
Small Scale ◽  
Fiber Reinforced ◽  
Graphene Nanoplatelet ◽  
Relaxation Properties ◽  
Polymer Hybrid ◽  
Carbon Fiber Reinforced

A nested analytical method, a product of combining two micromechanical models is developed in this study. The proposed micromechanical method predicts the relaxation properties of polymer hybrid nanocomposites containing linearly visco-elastic matrix, transversely isotropic elastic carbon fibers, and graphene nanoplatelets. Calculations performed in this model are of two scales. The small scale, which is the domain of epoxy resin and graphene nanoplatelet interactions, and the large scale, which assumes the small scale as a homogenized isotropic matrix. In the large scale, the prescribed matrix is then reinforced by the unidirectional CFs. Each scale calculation gives the properties of the underlying material. Secant moduli and the field fluctuation techniques are adopted in this study. Resulting explicit formulae allows one to calculate the overall relaxation moduli of the graphene nanoplatelet/carbon fiber-reinforced polymer hybrid nanocomposites. By comparing the data obtained by experiments and the results extracted by the proposed micromechanical approach, the accuracy of the model becomes apparent. Addition of graphene nanoplatelets into the fibrous composites leads to an improvement in the relaxation properties of the hybrid nanocomposites. Also, the elastic properties of graphene nanoplatelet/carbon fiber-reinforced epoxy hybrid nanocomposites are reported. The role of graphene nanoplatelet agglomeration, frequently encountered in real engineering situations, in the mechanical response of unidirectional hybrid nanocomposites is examined. The effects of volume fraction of graphene nanoplatelets and CFs on the overall mechanical properties are investigated.

Ultrasonic-Impregnation for Fiber-Reinforced Thermoplastic Prepreg Production

2017 ◽  
Vol 742 ◽  
pp. 17-24
Author(s):  
Steve Sockol ◽  
Christoph Doerffel ◽  
Juliane Mehnert ◽  
Gerd Zwinzscher ◽  
Steffen Rein ◽  
...  
Keyword(s):  
Large Scale ◽  
Matrix Material ◽  
Scale Up ◽  
Small Scale ◽  
Hydraulic Pressure ◽  
Scale Production ◽  
Fiber Reinforced ◽  
Technological Parameters ◽  
Ultrasonic Technology ◽  
High Processing

Fiber-reinforced thermoplastics have a high potential for big scale light weight process applications due to low processing times and recyclability. Further advantages are the low emissions during the manufacturing process and beneficial handling and storing properties of the semi finished materials. Thermoplastic composites are made of reinforcement fibers and a thermoplastic polymer matrix by applying two essential sub processes: (1) melting of the matrix-material and (2) impregnating the textile component with molten matrix-material. At present state of art both sub-processes are applied by using double-belt-presses, characterized by high processing temperatures and high processing forces. Therefore, a large amount of energy is needed to create the necessarily high compaction forces and temperatures with hydraulic cylinders and electric heating. Convection, infrared-radiation and the cooling (dynamic) of tempered machine parts leads to a significant dissipation of energy. Especially the process for generating the hydraulic pressure has a low level of efficiency. Therefore, in respect to economic and ecologic reasons, novel energy-efficient impregnation processes need to be investigated and developed. The represented novel impregnation process is based on ultrasonic technology. A stack of polymer film (outer layers) and a textile ply (inner layer) is formed and the energy is applied with an ultrasonic sonotrode. The efficient, fast and strongly concentrated energy application into the thermoplastic films allows the development of novel and highly flexible machine concepts. These can be used for development of small scale up to large scale production processes. The ultrasonic-technology allows a continuous impregnation of the textile component with molten matrix-material. A custom-designed prototype was developed. First material samples were produced and the technological parameters studied. A characterization of the experimental results, material samples, prototype machine and process is the focus of this paper.

Investigation of the recycling of continuous fiber-reinforced thermoplastics

2018 ◽  
Vol 32 (3) ◽  
pp. 342-356 ◽  
Author(s):  
Bing Liu ◽  
Peng Zhu ◽  
Anchang Xu ◽  
Limin Bao
Keyword(s):  
Large Scale ◽  
Small Scale ◽  
Specimen Thickness ◽  
Limited Information ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
Recycling Technology ◽  
Reinforced Thermoplastics ◽  
Simple Technology ◽  
Fiber Reinforced Thermoplastics

There is limited information on the recycling of continuous fiber-reinforced thermoplastics (FRTPs). Furthermore, existing research has been conducted in laboratories on a very small scale. In this article, we propose an effective and simple technology for recycling of FRTPs, which can be conducted on a large scale. To accelerate the rate of resin dissolution, prepared FRTPs were cut into small pieces. The obtained pieces were used to manufacture recycled chopped fabric tape-reinforced thermoplastics (R-CTTs). The feasibility of the recycling technology was confirmed by comparing the mechanical properties of the composites made from virgin materials (virgin chopped fabric tape-reinforced thermoplastics (V-CTTs)) and recycled materials. There was a significant improvement of the tensile properties with the increase of the specimen thickness. The strength of the materials was more sensitive to the length of the chopped tape than the modulus. Fibers in both V-CTT and R-CTT were well connected with the resins, as confirmed by scanning electron microscopy.

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