Composite Propeller Blade Research Articles

Hydro-elastic aspects of a composite marine propeller in accordance with ply lamination methods

In a composite material, stiffness and strength in a desired direction can be controlled via the combination and stacking of materials. As such, the application of composite materials has spread to almost every industry. To utilize this advantage in the design of a marine propeller with complex geometry, accurate and practical analysis tools that consider both the hydroelastic behavior and ply-stacking structure of composite materials are required. Therefore, steady and unsteady BEM–FEM FSI algorithms of a composite propeller blade and a simple finite element model that considers the lamination modulus of fiber materials have been introduced in this study. In addition, a comparative study using CFD–FEM-based FSI analysis and numerical investigation of the hydroelastic behavior of a composite propeller in the ship wake field have been performed based on the present methodology.

On the use of bend–twist coupling in full-scale composite marine propellers for improving hydrodynamic performance

Marine propellers are designed to work for a particular operating condition. However, a propeller often requires to operate at different off-design conditions, when its hydrodynamic efficiency drops. In this paper, a comprehensive numerical study is presented on the use of bend–twist coupling of composite propeller blades for improving their hydrodynamic efficiency at off-design conditions. The analysis is carried out on a full-scale propeller of diameter 4.2m, considering the complete viscous turbulent flow, as the loading and deformation of model propellers that have been typically studied in literature for this purpose cannot be extrapolated to a full-scale prototype propeller. The open water performance is estimated using the finite volume method employing the pressure based RANS equation for the steady, incompressible, turbulent flow. The deformation analysis is done using the finite element method based on the first order shear deformation theory for composite laminates. The fluid–structure interaction is incorporated in an iterative manner. The effect of laminate configurations on the maximum twist achieved in the blade is studied for four different composite materials. The numerical study reveals that, within the limits of material safety, the twist generated in the deformed propeller using commonly used composite materials is inadequate to create any noticeable change in the hydrodynamic efficiency. When the material failure is ignored, however, it is possible to generate sufficient deformation and twist that can cause appreciable improvement in the hydrodynamic performance.

Bi-directional fluid–structure interaction for large deformation of layered composite propeller blades

Bi-directional fluid–structure interaction becomes important when viscous flow changes the geometry of the domain significantly because of the pressure load. Large deformation in domain causes numerical convergence problems, which are solved by mesh smoothing, re-meshing and a time discrete iterative solver algorithm using industrial computational fluid dynamics and finite element analysis code. In this paper, this approach is used for laminated composite propellers considered as mixers. It experiences heavy thrust, which causes large deformations. Each layer of laminate is modeled as a solid element with anisotropic material data. Comparative study is presented between uni-directional and bi-directional fluid–structure interaction for mixer blades. Change in pressure distribution, stress distribution, thrust, torque and pitch angle of the blade are presented in later parts of the paper.

Dynamic response of a composite propeller blade subjected to shock and bubble pressure loading

The interaction between an underwater explosion and a composite propeller involves several physical phenomena that an accurate numerical simulation needs to capture. These include proper description of the initial explosion shock wave, of its propagation in the water, and of its interaction with the propeller blades and any other neighboring boundaries. In this work, a numerical procedure which links a compressible flow solver with an incompressible flow solver is applied to capture both shock and bubble phases efficiently and accurately. Both flow codes solve the fluid dynamics while intimately coupling the solution with a finite element structure code thus enabling simulation of full fluid–structure interaction. This numerical approach is applied to the simulation of the interaction between an underwater explosion and a multi-layered propeller blade made of a set of composite materials. Fiber orientation in the various layers is studied to understand which combinations of materials and fiber orientations give the strongest resistance in terms of both bending and twisting of the blade.

Base Line Study for Determination of Effect of Stacking Sequence on Vibration Characteristics of Composite Propeller Blade

An investigation of a conventional propeller made from composite materials was conducted in which its vibration characteristics were studied. Optimized designing of a composite propeller was performed for various constrained and unconstrained design objectives. Only symmetric ply stacking sequences were considered. Results show that the ply stacking sequence has an effect on the characteristics of a conventional propeller. Proper stacking sequence of the composite propeller improves its performance as compared to its metallic counterpart. The finite element method is used to calculate the resulting natural frequency and mode shapes of the propeller blades. In the present study the shapes of the propeller blade is modelled as cantilever discretized into various number of hexahedral and pentahedral finite elements. Propeller vibration characteristics are calculated by ply orientation angles, for achieving the desired objectives Ansys and Radiosis solvers are used. From the results it can be made clear that by proper selection of optimum number of layers from 8 to 16 and tailoring the ply orientation angles operational frequencies of composite materials can be further enhanced and can be made much stiffer than metallic one.

Free Vibration Characteristics of Metallic Propeller Blade Replaced with Composite Material Using Finite Element Approach

Structural vibrations problems presents a major hazard and design limitation for a wide range of engineering problems. A comprehensive study of vibration phenomena includes determining the nature and extent of vibration response levels. This paper focuses in determining suitability of composite material in replacement of metallic material for assessing the dynamic characteristics of the blade. This study reviews the natural frequencies and associated mode shapes for a pre twisted composite propeller blade for marine applications. MAB and composite are used .composite with symmetric and balanced stacking sequence were analyzed. From the results it can be concluded that by further changing the layup sequence composite materials can be made much stiffer than MAB propeller.

Study on Design of High Efficiency and Light Weight Composite Propeller Blade for a Regional Turboprop Aircraft

Study on Design of High Efficiency and Light Weight Composite Propeller Blade for a Regional Turboprop Aircraft

고속 터보프롭 항공기용 고효율 경량화 복합재 프로펠러 블레이드 설계 연구

본 연구에서는 한국의 차세대 중형항공기에 사용될 고속형 터보프롭 항공기용 고효율 복합재 프로펠러 블레이드의 설계를 수행하였다. 와류 이론과 블레이드 깃 요소 이론을 활용하여 기본 공력설계 및 성능 해석을 수행하였고 공력설계 결과는 상업용 전산유체해석 프로그램인 ANSYS를 이용한 해석을 통해 확인 되었다. 프로펠러 구조 설계 시 카본/에폭시 복합재료가 적용되었으며, 경량화와 구조 안정성 개선을 위하여 스킨-스파-폼 샌드위치 구조 형식를 채택하였다. 제안된 프로펠러 블레이드는 공력 및 구조 해석과 시제품 프로펠러 블레이드의 구조 시험을 통하여 높은 효율과 안전한 구조임이 검토되었다. In this study, designs of the high efficiency composite propeller blade for a high speed turboprop aircraft, which will be used for a next generation regional commercial aircraft in Korea, are performed. Both the vortex theory and the blade element theory are used for preliminary aerodynamic design and performance analysis of the propeller. Then the aerodynamic design result is confirmed through performance analysis using a commercial CFD code, ANSYS. The carbon/epoxy composite materials is used, and the skin-spar-foam sandwich type structure is adopted for improvement of lightness and structural stability. Finally, it is investigated that the proposed propeller blade has high efficiency and structural safety through both aerodynamic and structural analysis and experimental test of a prototype propeller blade.

Scaling of the Transient Hydroelastic Response and Failure Mechanisms of Self-Adaptive Composite Marine Propellers

The load dependent deformation responses and complex failure mechanisms of self-adaptive composite propeller blades make the design, analysis, and scaling of these structures nontrivial. The objective of this work is to investigate and verify the dynamic similarity relationships for the hydroelastic response and potential failure mechanisms of self-adaptive composite marine propellers. A fully coupled, three-dimensional boundary element method-finite element method is used to compare the model and full-scale responses of a self-adaptive composite propeller. The effects of spatially varying inflow, transient sheet cavitation, and load-dependent blade deformation are considered. Three types of scaling are discussed: Reynolds scale, Froude scale, and Mach scale. The results show that Mach scaling, which requires the model inflow speed to be the same as the full scale, will lead to discrepancies in the spatial load distributions at low speeds due to differences in Froude number, but the differences between model and full-scale results become negligible at high speeds. Thus, Mach scaling is recommended for a composite marine propeller because it allows the same material and layering scheme to be used between the model and the full scale, leading to similar 3D stress distributions, and hence similar failure mechanisms, between the model and the full scale.

Vibration and damping analysis of a composite blade

This paper is concerned with the damping design of a composite propeller blade. A hybrid method is proposed for predicting the structural damping of the composite blade. This method consists of the statistical prediction of high-frequency material damping, the numerical calculation of modal damping, and the conceptual modification of Rayleigh damping. The vibration damping experiment is carried out to investigate the validity of the hybrid method. The effects of fiber orientation angle and stacking sequence on the damping characteristics are investigated. The damped dynamic responses of the composite blade under parametric variations are evaluated. The results show that the dynamic performance of the composite structure can be improved by completing the damping design.

Dynamic Responses of Composite Marine Propeller in Spatially Wake

Dynamic responses of a composite marine propeller in spatially wake were investigated in this paper. A hydroelastic model was developed to identify the response characteristics of the composite propeller blades using a finite element method (FEM) coupled with a computational fluid dynamics (CFD) method. Rotational effects and added mass were considered. A coupled matrix was established and solved by the Newton-Raphson numerical procedure. The dynamic characteristics and responses of the composite blade were calculated and compared with those of the counterpart rigid blade. Effects of various parameters, including the layer lamination and fiber orientation were investigated.

Hydroelastic tailoring of flexible composite propellers

This paper describes and demonstrates a method for the hydroelastic tailoring of flexible composite marine propeller blades. This method is applicable to situations in which the propeller's shape adapts to changing flow conditions due to its rotation in a spatially varying wake, resulting in improved efficiency when compared to a rigid propeller. The unloaded shape of the flexible propeller and the composite lay-up are determined using an optimisation procedure. Design calculations for an example propeller revealed an improvement in the performance over a range of operating conditions. However, this may have been greater if, first, the geometry of the rigid propeller that was the basis of the flexible propeller was optimised so that it was more suited to take advantage of the hydroelastic tailoring, and second, composite materials were selected to maximise flexibility within the strength requirements. Also, a closed-form expression was developed for estimating the efficiency gain of a flexible propeller at the design condition in a spatially varying wake flow. The potential benefit of a flexible propeller is that it broadens the efficiency curve and reduces the sensitivity of the losses usually manifested in the spatially varying wake flow.

Effects of Stacking Sequence on Nonlinear Hydroelastic Behavior of Composite Propeller Blade

AbstractA coupled structural and fluid flow analysis was performed to assess the hydroelastic behavior of a composite marine propeller. The finite element method and lifting surface theory were applied in the structural and fluid analyses, respectively. A coupled equation derived from the Bernoulli equation and the hydrostatic pressure in terms of the blade deflection and strength of the vortex was solved by Newton-Raphson procedure. A MAU 3–60 propeller was analyzed with different stacking sequences of composite layup. The hydroelastic behaviors of the propeller with balanced and unbalanced stacking sequences were investigated and discussed. The unbalanced Stacking sequences were shown to influence the performance of the composite propeller, especially in the region in which the advanced coefficient is low.

Analysis of Underwater Free Vibrations of a Composite Propeller Blade

The free vibration characteristics of a composite marine propeller blade were studied. MAB and composite materials were used. Composites with symmetric, balanced and unbalanced stacking sequences were analyzed. Rotational effects and added mass were considered using the finite element method. The natural frequency of the blade in water was much lower than in air. The mode shapes of the blade are almost the same in air as in water. The anisotropy of the composites shift the contours of the mode shape. Generally, greater anisotropy corresponds to a lower natural frequency. The rotational effects can be ignored because the marine propeller rotates slowly.

Strength Evaluation of a Composite Marine Propeller Blade

The strength of a composite propeller blade is evaluated by performing a nonlinear hydroelastic analysis. The finite element method, lifting surface theory, least square method, equilibrium equation, and Hashin failure criteria are employed for the structural analysis, fluid analysis, stress smoothing, three-dimensional stress calculation, and strength assessment, respectively. Additionally, the strength of the blades with balanced and unbalanced stacking sequences are evaluated and discussed. Five failure modes, fiber tension and compression, matrix tension and compression, and delamination are considered. The strength is shown to be insufficient for the blades with [.../452/90/0]S. Meanwhile, the blades with [.../2/90/0]S and [.../15/15/90/0]S are shown to have sufficient structural strength. However, attention shall be paid to the delamination failure at the leading and trailing edges of the blade.

Fatigue testing of a composite propeller blade using fiber-optic strain sensors

The performance of surface-mounted extrinsic Fabry-Perot interferometric (EFPI) sensors during a seventeen-million-cycle, high-strain fatigue test is reported. Fiber-optic strain measurements did not degrade during the test. The sensors were applied to a composite propeller blade subject to a constant axial load and a cyclic bending load. Strain measurements were taken at four blade locations using two types of EFPI sensors and co-located electrical resistance strain gages. Static and dynamic strain measurements were taken daily during the 65 days of this standard propeller-blade test. All fiber-optic sensors survived the fatigue test while most of the resistive gages failed. The suitability of fiber-optic monitoring for fatigue testing and other high-cycle monitoring is demonstrated.

Aeroelastic tailoring analysis for preliminary design of advanced propellers with composite blades

An analytical study of aeroelastic tailoring has been conducted to determine the flutter characteristics of advanced turbo propellers for preliminary design purposes. The structural dynamic model for composite propeller blades is combined with an unsteady cascade theory with three-dimensional corrections to produce an aeroelastic analysis tool for pretwisted propeller blades with homogeneous anisotropy exposed to a high subsonic flow. The free-vibration analysis of the SR-3 propeller model built of unidirectiona l graphite/epoxy , revealed that the first-bending frequency of the blade can be changed by 53% from the baseline value by changing fiber orientation. Using/?-k modal flutter analysis it was also found that the fiber orientation with a little larger sweep angle than that of the elastic axis can eliminate flutter without any weight penalty, and that the corresponding first natural mode has the least bending-torsion coupling. However, the flutter velocity is sensitive to fiber orientation and interblade-phase angle.

Aeroelastic tailoring analysis for advanced turbo propellers with composite blades

The development of unsteady aerodynamic analysis with computational fluid dynamics important for investigating the aeroelastic characteristics of rotors made of advanced composite materials. The purpose of the present analysis is to establish an aeroelastic model useful for the preliminary design of advanced turbo propellers. An unsteady aerodynamic model of high subsonic cascade airfoils, including sweep effects and finite span effects, is combined with a structural dynamic model for composite pretwisted propeller blades to produce an aeroelastic analysis tool. The p-k modal flutter analyses for the SR-3 propeller model (made of graphite/epoxy) were conducted. They revealed that suitable combinations of the fiber orientation can eliminate flutter without any weight penalties or strength penalties and that the flutter velocity is found to be sensitive to the interblade phase angle as well as the fiber orientation. These results indicate the effectiveness of aeroelastic tailoring for advanced turbo propellers and also the usefulness of the present analysis.

Environmental Testing for Civil Certificate of Composite Propellers

Synopsis Results of environmental tests on composite propeller blades, including bird and lightning strikes, are compared to observations made during twelve years' operation of composite propeller blades on hovercraft.

Measuring In-Plane Shear Properties of Glass-Fiber/Epoxy Laminates

For design analysis of the fiber composite propeller blade, the moduli and strengths of two commonly used typical laminates consisting of a 50-vol % glass fiber in an epoxy were determined. Three basic test methods for determining in-plane shear properties of glass/epoxy laminates were evaluated: twist, shear, and off-axis tensile. The advantages and disadvantages of these methods are explained from the experimental viewpoint.