Effect Of Ply Angle Research Articles

Interfacial strengthening mechanism of SS/CFRTP/SS composite components prepared by mixed co-punch

Aiming at the preparation and forming of SS/CFRTP/SS composite components (CFRTP, thermoplastic carbon fiber composites; SS, stainless-steel), a mixed co-punching forming method of carbon fiber composites and stainless-steel is proposed. The effects of different surface treatments of stainless-steel on the shear strength, bending strength and crushing energy absorption of SS/CFRTP/SS composite components were also investigated, and the effects of ply angle on crushing energy absorption and bending strength of composites components were studied. The results show that the effect of SS/CFRTP/SS composite components prepared by mixed co-punching is very ideal. The bending strength of SS/CFRTP/SS composite component with 0 °/45 °/90 ° ply is the best, and the 0-direction ply has the best energy absorption effect. The addition of PA6 material between layers did not enhance the effect. The mechanical properties of SS/CFRTP/SS composite components with coupling agent after wire brush grinding are better than those obtained by only wire brush grinding. XPS analysis shows that the added silane coupling agent becomes a bridge to transfer stress load between the two materials through chemical reaction with the surfaces of the two materials. The micropores formed after surface treatment of stainless-steel form interlocking connection with CFRTP matrix. The excellent composite effect of SS/CFRTP/SS composite components is the result of physical and chemical interaction.

Effect of ply angle on the burst pressure of composite pressure vessels by filament winding

Composite pressure vessel is important structure in different application include pipe and pipe under pressure , the closed system pipe under high pressure and temperature such as gas pipe line and aircraft structure . because of the characteristics of polymer – composite as alternative of heavy materials as metal of various application. The current work focus on the study of strength phase orientation and there properties on the burst pressure strength and other parameter ,which are very important in design and manufacture of these vessel such as selection of type of strength phase nylon 6,6 and philosophy of mixing of there type of fiber with matrix material (epoxy). The work also include the study the effect the two layer angle ply [0/90],[55/-55],[75/-75] and implementation the different material testing to evaluate the toughness and stiffness of these vessel and compare the experimental result with theoretical result. The filament winding apparatus was designed and executed to manufacturing of different type patron according to these angle of ply nylon fiber the mechanical tensile test ,drop test ,pipe stiffness test ,hydrostatic pressure test are use to test these vessel . The results shown that ply orientation [75/-75] have high tensile properties , high toughness, high stiffness result , high impact result , high burst pressure result than other ply orientation . so that [75/-75] ply orientation is optimal angle of vessel. Tensile test shown that [75/-75] ply orientation sample have higher properties in two direction longitudinal and transverse direction than other samples.

A theoretical study on nonlinear in-plane buckling of shallow angle-ply laminated arches with elastic supports

This paper presents, for the first time, an analytical study on the nonlinear in-plane buckling of angle-ply laminated shallow arches with elastic supports under a uniform radial loading. To decouple internal forces and facilitate theoretical derivations, the nonlinear equilibrium path and buckling equation are established based on neutral plane formulation by using a virtual work method, from which the closed-form solutions for limit point buckling and bifurcation buckling are determined. The buckling mode of the laminated arch is characterized by introducing the modified slenderness ratio. The present analysis is verified through direct comparisons with finite element results. The effects of radial and circumferential stiffnesses of the elastic supports on the buckling behaviors are discussed in detail. It is found that the laminated arch may buckle in either a limit point mode or a bifurcation mode and its buckling behavior is highly sensitive to the support stiffness. The effects of ply-angle on the critical buckling load are also researched. It is found that the buckling loads of laminated arches decrease with an increase of flange and web ply-angles, and the influence of flange ply-angle on buckling load is more pronounced than that of web ply-angle.

Effects of ply angle and blocking on open-hole tensile strength of composite laminates: A design and certification perspective

The failure strength of carbon-fibre reinforced plastic laminates under open-hole tension varies considerably with ply angle, ply blocking and loading direction. Here, laminates with various standard-angle and non-standard angle stacking sequences are subjected to both on- and off-axis loading in a comprehensive experimental and progressive damage finite element analysis testing campaign. It is found that interlaminar and intralaminar matrix damage can be beneficial when accumulated sub-critically in ply blocks aligned with loading direction, but can also lead to significant strength decreases owing to edge failure. In such cases, a numerical edge treatment is proposed for more accurate representation of open-hole tensile strength in large structures where holes are positioned away from free edges. The solution suppresses edge failure and results in up to 80% strength increases, challenging the validity of standard open-hole tension testing and current design rules for some applications.

Flexural behaviour of carbon and glass reinforced hybrid composite pipes

This paper presents a study on the flexural behaviour of hybrid composite pipes reinforced with carbon and glass fibres. The progressive failure of composite pipes in three point bending was modelled numerically by Finite Element Analysis (FEA). The FEA based model was validated against the experimental data. With this developed model, the effects of ply angle, fibre volume fraction and hybridisation have been found. It is shown from the results that the maximum bending loads occur when the ply angle is between 60° and 75° The hybrid composite pipe has comparable failure loads compared to the full carbon fibre composite pipe or the full glass fibre composite pipe.

Effect of ply angle on nonlinear static aeroelasticity of high-aspect-ratio composite wing

In order to reduce the weight and improve aerodynamic characteristics, the new aircraft generally adopts lightweight composite materials and high-aspect-ratio layout. Such the structural layout aircraft will produce large nonlinear aeroelastic deformation under the action of aerodynamic loads. Due to the anisotropy of the composite, the composite ply angle of wing skin has a great influence on the elastic deformation of the high-aspect-ratio wing. In order to study the influence of the ply angle on the nonlinear static aeroelastic wing deformation, based on CFD/CSD unidirectional fluid-solid coupling, the structural deformation and stress of high-aspect-ratio composite wing were numerically solved. The wing deformation along the lift direction was taken as the optimization target. The structure strength was taken as the constraint. The ply angle for the composite skin of the high-aspect-ratio composite wing was optimized by the Screening method. The optimization results show the nonlinear static aeroelastic deformation of the wing in the lift direction is reduced by 39.1 %. The maximum stress of the wing beam and rib is reduced by 39.0 %. The maximum Tsai-Wu failure factor of the wing skin is reduced by 47.1 %.

Flapwise vibration analysis of rotating composite laminated Timoshenko microbeams with geometric imperfection based on a re-modified couple stress theory and isogeometric analysis

This paper makes the first attempt to establish a size-dependent finite element formulation by combining isogeometric analysis and a re-modified couple stress theory (RMCST) for anisotropic elasticity. The flapwise vibration of rotation composite microbeam with geometrical imperfection connected to a hub is explored. This paper employs the NURBS function as the basis function to describe the geometry and overcomes the inherent difficulty of constructing higher order continuous displacement function for modified couple stress theory based finite element formulation. Besides the angular velocity, slender ratio, scale parameter, and maximum imperfection amplitude, the effect of ply angle on the flapwise vibration of rotation composite microbeam is investigated in this paper for the first time. This investigation demonstrates that we can control the natural frequencies of rotating beam by designing composite laminates in different stacking sequences.

Evaluation of stiffness in a cellulose fiber reinforced epoxy laminates for structural applications: Experimental and finite element analysis

Abstract Natural fiber composites have been proved to have the ability to replace the synthetic fiber composites in many structural applications. Unprecedented growth in the field of computational techniques has opened the doors of analysis and simulation of composite materials under various environment. Modelling and simulation using various available softwares saves a lot of time and resources. In the present work, an attempt has been made to analyze the tensile behavior of jute fiber reinforced epoxy based polymer composite materials using the student version of commercially available finite element code Siemens PLM NX 10.0. In most of the structural applications, materials are required to have enough stiffness to resist the shape deformation under normal loading conditions. Therefore, emphasis is given to the load-deformation behavior of the developed composites. A 3-dimensional model of the test specimen was developed using ply-stacking method and the strain-stress values were verified by the available literature. The model showed a good agreement between the experimental and software results. Effect of ply angle, fiber percentage, fiber type, number of layers and weft fiber angle on the stiffness of laminate have been studied.

Numerical analysis of the mechanical behaviour of reinforced thermoplastic pipes under combined external pressure and bending

Reinforced thermoplastic pipes (RTPs) are promising design solutions for deep-water riser applications due to their light weight, high performance and good spoolability. For such applications, RTPs experience significant ambient pressure and sustain bending and/or tension loads during the installation and operation phases. Normally an RTP is composed of an inner Polyethylene (PE) liner, reinforced layers made from fibre-reinforced PE composites and an outer PE cover. The mechanical behaviour of such an RTP when it has been subjected to combined external pressure and bending has been studied through finite-element analysis (FEA). The nonlinear mechanical behaviour of both PE and the fibre-reinforced PE composites has been modelled by developing numerical algorithms that reflect the strain-dependent mechanical characteristics of PE. These algorithms are implemented in the analysis tool used, Abaqus/Standard, with the user subroutine, UMAT. The proposed FE model could accurately simulate the buckling and post-buckling response of the RTP and predict its failures under the combined external pressure and bending. Rotation-pressure interaction collapse envelopes of the RTP in different loading paths are generated. Additionally, the effects of ply angles, loading paths and diameter-to-thickness (D/t) ratios on the performance of the RTP under this loading case are investigated. The results obtained could be used to improve the design of RTPs for deep-water riser applications in the offshore oil and gas industry.

Vibration and Stability of Variable Cross Section Thin-Walled Composite Shafts with Transverse Shear

A dynamic model of composite shaft with variable cross section is presented. Free vibration equations of the variable cross section thin-walled composite shaft considering the effect of shear deformation are established based on a refined variational asymptotic method and Hamilton’s principle. The numerical results calculated by Galerkin method are analyzed to indicate the effects of ply angle, taper ratio, and transverse shear deformation on the first natural frequency and critical rotating speed. The results are compared with those obtained by using finite element package ANSYS and available in the literature using other models.

Aeroelastic Behavior of Morphing Wing in Flutter Regions

A morphing of a system is capable of changing the shape from the cruise to dash configurations. During the motion, the aerodynamic and structural characteristics can be varied tremendously, and the new shape will induce the different aeroelastic stability behavior. Thus, the purpose of this study is to investigate the flutter analysis of the folding wing structure including the effect of various parameters such as fold angles et al. of the composite laminates structures. For doing this these works, the aero-elastic analysis of folding wing is performed with respect to the parameters using PK method. Also, Finite Element Method is used in structural analysis, and Doublet Lattice Method is applied in aerodynamic analysis. Generally, the dynamic pressure and frequency during the flutter are sensitive to the structural characteristic, thus the flutter mode alteration is occurred by changed natural frequencies. Also, the alteration causes the flutter dynamic pressure variation. Therefore, results represent the aeroelastic stability variation due to the folding wing system including the effects of ply angles of composite laminates.

The Effects of Ply Angle of Laminated Composite Plates on Wind Induced Vibration

This paper presents an analysis on the effect of ply angle for laminated composite plates on wind induced vibration. With Hamilton’s principle and the Rayleigh-Ritz method, the equation of motion for the wind induced vibration is derived. The displacements in time domain and the mean-square value of the transverse response under wind pressure are studied for laminated plates with different ply angles. From the numerically simulation results it is seen that the ply angle of the laminated plate can significantly affect the wind induced vibration. For different rectangle plate the optimal ply angles of minimum displacement is different. The analytical methodology in this paper can be expanded to other kinds of random vibration such as water flow induced vibration.

Anisotropic Heat Analysis Using Hybrid Finite Element Model with Element Boundary Integrals

Anisotropic materials have been widely applied in practical engineering problems of interest. In the paper, the anisotropic heat transfer behaviors are analyzed using the proposed hybrid finite element model with Green’s function kernel. In the established weak integral hybrid functional, the element internal field being approximated with the combination of Green’s function satisfies a priori the governing partial differential equation and the independent frame field is assumed to link the internal field. As a result, the solving linear system of equations with boundary integrals only is obtained and the constructed elements show anisotropic feature. Two numerical examples are given to show the convergence and accuracy of the proposed approach, and the effect of ply angle of orthotropic material principal direction on the temperature distribution is discussed to investigate heat transfer mechanism in anisotropic materials.

Heterogeneous Thermo-oxidative Behavior of Multidirectional Laminated Composites

This article examines the through-the-thickness heterogeneity observed in oxidation profiles of composite laminates. The effect of ply angle on oxygen diffusivity and the influence of ply stacking sequence on oxidation behavior of isothermally aged multidirectional composites are discussed by correlating experimental observations and a three-dimensional oxidation model. Experimental observations of oxidation growth are made using dark-field optical microscopy, while damage initiation and growth is detected using fluorescence imaging with dye impregnation. Oxidation growth in laminated systems is simulated using a diffusion-reaction-conversion model developed earlier for resin oxidation along with homogenization techniques. Several stacking sequences of carbon fiber-reinforced polyimide composites are studied. The effects of the orthotropy in the diffusivity tensors of each ply and the influence of neighboring ply on oxidation growth are clearly illustrated. The simulation results presented in this article are valid till the onset of damage, beyond which coupling effects between oxidation growth and damage evolution have to be addressed.

Prediction of stitch crack evolution and gas permeability in multidirectional composite laminates

Stitch cracks in multidirectional laminates were observed by many researchers in the literature. In the present work, the damage evolution in multidirectional laminates is investigated using the strain energy release rate concept. Two methods are used to compute the strain energy release rate. The effects of ply angle and ply thickness on stitch crack evolution are investigated. Then, a model based on Darcy’s law for porous materials is developed for predicting gas permeability in composite laminates containing microcracks and delaminations. Gas permeability is presented as a function of crack density and crack intersection area. Then the intersection areas formed by crack opening displacements are computed using 3D finite element analysis. The progressive gas permeability in multidirectional laminates is predicted and compared with the gas permeability predicted in the cross-ply laminates in our previous work.

Stall Flutter Analysis of High-Aspect-Ratio Composite Wing

The stall flutter characters of high- aspect- ratio composite wing are investigated, and the effects of structure geometric nonlinearity and stiffness couple created by composite anisotropy on them also are discussed. Firstly, the high- aspect- ratio wing is modeled as a composite thin- walled closed- section Euler beam whose displacement and rotation both could be of finite value, and the nonlinear dynamic equations is build up on it with all the effects of geometric nonlinearity, aerodynamic nonlinearity and anisotropy of material being considered. Then vibration equations are deduced through perturbing the dynamic equations at wing's equilibrium position, and coupled with unsteady stall aerodynamic model and ONERA model, to obtain the nonlinear stall flutter analysis equations of wing. Finally, the flutter stabilities with various wind speeds are determined by the harmonic balance method. With several examples, the validity of the stall flutter model is proved, and the significant effects of geometric nonlinearity on the stall flutter various characters as well as the effects of ply angle on the stall flutter speed and frequency also are discussed.

Energy Absorption Behavior of Double-Chamfer Triggered Glass/Epoxy Circular Tubes

The effects of double-chamfer triggered pattern to the axial crushing energy absorption behavior of glass/epoxy circular tubes with the ply pattern of [±θ]n is reported. Deliberate weakness of 45 chamfered triggers at both ends of the tube is introduced with the aim of controlling the crushing performance. Similar to single-chamfer triggered pattern, application of this trigger pattern is an efficient way to weaken the initial peak load Pcr, extend the triggering length Ltr, reduce the probability of catastrophic failure and avoid unstable crushing. The crushing behaviors, the damage characteristics of untriggered, single-chamfer triggered and double-chamfer triggered tubes were studied in detail. Specific crushing stress was used to measure the energy absorption for tubes of different winding angles. Investigations on the macroscopic collapse mode of the tube, the effects of ply angle, the effect of impact loading and quasi-static loading were performed in the presence of double-chamfer triggers.