Design Of Composite Blades Research Articles

Design, Manufacture and Testing of an Open-Source Benchmark Composite Hydrokinetic Turbine Blade

In a trend towards clean energy alternatives, recent years have seen great strides in the marine energy space. This has resulted in a pressing need for the design, development, and validation of novel energy harvesting technologies such as hydrokinetic devices, which capture kinetic energy from waves, tides, and currents. However, these devices span numerous concepts and designs that often lack solid benchmark research that can be freely referenced. This work focuses on the design process of an open-source composite hydrokinetic turbine blade for a three-bladed marine turbine rotor assembly with a diameter of 2.5 m. The proposed blade consists of two structural composite skins that are bonded with an adhesive and filled with a foam core. This study will explore and contrast the efficiency and resolution of low-fidelity rapid design methodologies and comprehensive high-fidelity approaches for the blade design, modeling, and analysis efforts, a key objective in this research. Blade hydrodynamic loads were modeled and applied to finite-element blade models to study deformations and potential failure. Ongoing efforts will result in blade manufacture and structural testing at the National Renewable Energy Laboratory. In future work, multiple blades will be deployed at the Living Bridge site at the University of New Hampshire and will be compared to rigid aluminum blades of the same geometry, developed by Sandia National Laboratories. Ultimately, this research will lay foundational groundwork for researchers and manufacturers, establishing a baseline composite blade design that will serve as a benchmark in the development of future hydrokinetic turbine blades.

Bird impact response and damage mechanism of 3D orthogonal woven composite aeroengine blades

Various gelatin simulated bird projectiles were used to impact two key positions of three-dimensional (3D) orthogonal woven composite stator blades used in aeroengines: the center and leading edge at the blade back. The effects of impact velocity, projectile weight, and impact position on the macro damage mode were determined. Numerical simulations were conducted using the constitutive model developed in our previous work (Liu et al. 2023). The numerical simulation results were in good agreement with the experimental results. Combined test results, micro-CT and SEM observation and the numerical simulation results, the internal damage mechanism of the blade was explored. Four types of damage modes were seen under bird strike: edge damage on the narrow blade root, cracks on both sides of the narrow blade root, damage in the impact area, and complete fracture. Furthermore, the impact energy thresholds for visible damage and fracture were obtained for different bird weights and impact locations, which is of great significance to the anti-bird-strike design of composite blades.

Similarity design method for dynamic characteristics of rotating composite blades in thermal environment

A similarity method for rotating composite blades in thermal environment is developed for the problems of difficulty, time consumption, high cost, and risk in the dynamic test under a high-temperature environment. Within this study, a set of scaling laws are derived for thin-walled composite plates based on their dynamic models and the applicability of the scaling laws is demonstrated in the similitude design of composite blades. The present dynamic model takes into account thermal stress and centrifugal stiffening effect. Analytical calculations show that the scaled models at relatively low temperatures can well reproduce the dynamic characteristics of their corresponding prototypes at high temperatures when taking into account the scaling of temperature change and rotational speed.

Design optimization and numerical verification of adaptive composite blades for hydro-turbine

In this paper, an adaptive composite blade is designed based on the composite mechanics and bending torsion coupling theory, and the blade structure is optimized by a multi-parameter and multi-objective optimization method. Furthermore, the dynamic interaction between the flow and structure domain during the bend-twist coupling process was also studied by the two-way fluid-structure coupling method to verify the hydrodynamic performance and structural performance of the optimized blade. The results show that the multi-parameter and multi-objective optimization method is suitable for the design of composite blades. The optimized blade has better hydrodynamic performance and structural performance, manifesting a higher energy utilization and less concentrated stress.

The preliminary design of a scaled Composite UHBR Fan for a wind tunnel test campaign

The ambition of the CA3ViAR project is to design an open test case fan that experiences instability mechanisms, which are representative for ultra-high bypass ratio (UHBR) fans of civil aircrafts, and to perform a comprehensive experimental investigation to measure aerodynamic, aeroelastic and aeroacoustic performance in a wide range of operational conditions. Experimental tests will be performed in the Propulsion-Test-Facility (PTF) of the Institute of Jet Propulsion and Turbomachinery (IFAS) of Technische Universität Braunschweig, Germany. The final objective of the project is to provide an open test case for the entire research community, with geometries, numerical and experimental results to establish a new reference for composite UHBR fan design. This will support the development of new methods and tools for the development of safer, lighter and more efficient composite fans for greener UHBR engines. In this work the preliminary design of the low transonic fan (LTF) to be used as test article, whose main requirement is to be operated in a safe and controlled way in conditions of aerodynamic and/or aeroelastic instability during wind tunnel operations, is presented. More in particular, consolidated aerodynamic design, strategy adopted to drive the structural design, flutter analysis taking into account acoustic reflection at the intake, dynamic and stress analyses, as well as aeroacoustic measurement optimization are presented and discussed. The preliminary mechanical design of composite blades and the rotor hub, together with the rotor instrumentation and related studies to embed sensors in the composite blades, are also part of this article, and complemented by manufacturing trials and demonstration tests give the full picture of all the project activities up to the preliminary design review.

Optimal design method for composite blades using stiffness weights

Bend–twist coupling effect of composite materials can be used to reduce blade torsion deformation and improve blade efficiency. In this study, stiffness weight coefficients and load coefficients were introduced to quantify the ply sequence and bend–twist load condition. Composite stator blades were simplified into symmetric unbalanced cantilever laminated to verify the stiffness weight coefficients and load coefficients. Moreover, the bend-twist coupling effect of the symmetric laminates with different ply angles and stiffness weight coefficients under various load coefficients was investigated through experiments, classical laminate theory, and finite element analysis. An optimization method using stiffness weight coefficients was proposed. The optimal goal is to minimize blade torsion and curvature to improve blade efficiency. And the global optimal solution using traversal search method was obtained to compare with the optimal solution in this method. A 40-ply blade was optimized using this method. The optimal results indicate that this method can reduce the calculation amount for the optimization by eliminating the ply combination which does not meet optimization goals, and the errors between optimal solution of this method and global optimal solution are acceptable. This optimization method can serve as a reference and basis for the optimal design of composite blades.

Optimization Method of Composite Blade Lay-up Considering Bent-Twist Coupling Effect

In the design of composite blades, the bent-twist coupling effect can be used to reduce the aeroelastic deformation of the blades by lay-up optimization design to improve the efficiency of blade structure. In this paper, the composite blade was simplified as symmetric unbalanced cantilever laminate, and based on the classical laminated theory(CLT), two analysis parameters are proposed:the stiffness weights and load factors. The influence of the two analysis parameters on the structural deformation of the bent-twist coupling effect is studied by experiments and finite element analysis(FEA). The symmetrical laminated plates containing 0°, 90° and ±45° plies were analyzed and calculated with the feasible region of stiffness weights as the constraint condition and the minimum blade curvature as the objective function, and the optimal path of the stiffness weights relate to the load factors was obtained. A 16-plies symmetric laminated plate was used as an example to verify the optimal path of the stiffness weights. By the inverse calculation of the optimal path of the stiffness weights, the optimal ply sequences can be obtained. The method of this paper may provide some references and basis for the optimal design of the composite blades.

Experience with the design of ultralight airplane with unconventional powerplant

Ducted fan-powered ultralight (UL) aircraft UL-39 Albi has been developed at the Department of Aerospace Engineering at Faculty of Mechanical Engineering of the Czech Technical University in Prague. The aircraft was manufactured by the companies LA Composite, s.r.o. and JIHLAVAN Airplanes, s.r.o. The development was funded by the Ministry of Education and the Ministry of Industry and Trade of the Czech Republic. The airframe is fully made of composite materials, mainly carbon fibre/epoxy resin prepregs, and was cured in autoclave. The design contains many unconventional features. These were necessary to meet legal requirements (i.e. maximum take-off weight and maximum landing speed) and to achieve high flight performance. This puts extreme demands to both maximisation of propulsion efficiency and minimisation of airframe and powerplant weight. This paper presents more than fifteen years’ experience with design of ducted fan powered ultralight aircraft. Some solutions of design trade-offs are presented, namely integration of engine into the fuselage, carbon composite blade design and lightweight airframe design.

Particle swarm-based structural optimization of laminated composite hydrokinetic turbine blades

Composite blade manufacturing for hydrokinetic turbine application is quite complex and requires extensive optimization studies in terms of material selection, number of layers, stacking sequence, ply thickness and orientation. To avoid a repetitive trial-and-error method process, hydrokinetic turbine blade structural optimization using particle swarm optimization was proposed to perform detailed composite lay-up optimization. Layer numbers, ply thickness and ply orientations were optimized using standard particle swarm optimization to minimize the weight of the composite blade while satisfying failure evaluation. To address the discrete combinatorial optimization problem of blade stacking sequence, a novel permutation discrete particle swarm optimization model was also developed to maximize the out-of-plane load-carrying capability of the composite blade. A composite blade design with significant material saving and satisfactory performance was presented. The proposed methodology offers an alternative and efficient design solution to composite structural optimization which involves complex loading and multiple discrete and combinatorial design parameters.

A Method of Structure Analysis for Complex Small HAWT Composite Blade Design

The air contain very low density of energy, as a result the complex 3D shape blade is required for maximize the energy extraction. The blades of the wind turbine will suffer the tough nature environment. The complex 3D shape blade with thick composite layers creates unique challenge for the design and structure analysis. The equivalent property of a composite layer that contains multiple plies of laminates is often used in the analysis of the thick composite structures. This study focused on a methodology to calculating the equivalent material properties on the 3D blade with thick composite layers. The research applies reverse engineering method to sample the blade material in order to get the equivalent material properties of complex composite 3D blade. By doing this, an equivalent material properties of composite blade can be used in the finite element analysis. The result can also provide a guide line for stress and fatigue design of blade.

Design and analysis of vertical axis thermoplastic composite wind turbine blade

There is growing interest in the use of thermoplastic composites for wind turbine blades. This paper presents preliminary work on the design, analysis and manufacture of a thermoplastic composite blade for a vertical axis wind turbine. The blade design featured a sandwich construction with commingled woven E-glass fibre/polypropylene thermoplastic composite skins and a polyethylene terephthalate (PET) foam core. A finite element modelling methodology has been developed for predicting the natural frequency and structural performance of the blade. For structural analysis, the skin was modelled with a composite damage model for which an inverse calibration procedure was developed. Vibration and static bending tests were conducted on a subscale prototype blade to validate the finite element models. A one-step vacuum moulding process was adopted to manufacture the prototype blade. The validated finite element models were then used to determine the natural frequency of the full sized blade and predict its performance under in-service aerodynamic loads. The results show that the thermoplastic composite blade design meets the desired structural requirements.

Enhancing the damping of wind turbine rotor blades, the DAMPBLADE project

AbstractA research programme enabling the development of damped wind turbine blades, having the acronym DAMPBLADE, has been supported by the EC under its 5th Framework Programme. In DAMPBLADE the following unique composite damping mechanisms were exploited aiming to increase the structural damping: tailoring of laminate damping anisotropy, damping layers and damped polymer matrices. Additional objectives of the project were the development of the missing critical analytical technologies enabling the explicit modelling of composite structural damping and a novel ‘composite blade design capacity’ enabling the direct prediction of aeroelastic stability and fatigue life; the development and characterization of damped composite materials; and the evaluation of new technology via the design and fabrication of damped prototype blades and their full‐scale laboratory testing. After 4 years of work a 19 m glass/polyester damped blade was designed, manufactured and tested using the know‐how acquired. Modal analysis of this blade at the testing facility of CRES showed a nearly 80% increase in the damping ratio of both the first flap and lag modes compared with the earlier, standard, design practice. Copyright © 2005 John Wiley & Sons, Ltd.