Composite Laminate Plates Research Articles

Transverse vibration of laminated-composite-plates with fillers under moving mass rested on elastic foundation using higher order shear deformation theory

Usually, the laminated-composite-plates (LCPs) are strengthened by altering the constituents. The use of nano-particles as filler is a new approach in this regard. Here, flyash and graphene are used as fillers in epoxy-based woven E-glass fabric-reinforced LCPs. The LCPs are often subjected to moving mass/load in use and it becomes necessary to study their stability. Further, foundation support has an important role in structural stability. Here, the response of LCPs resting on elastic foundations to a moving load is studied. A fifth-order plate-theory based on Eringen’s non-local model for LCPS with filler is followed and validated with finite-element-analysis (FEA) and other literature. The effect of the intensity of moving mass, its position on LCP, speed, the material variant, foundation constant, and damping ratio on the dynamicity of LCPs is then reported. It is observed that masses moving on the LCP induce instability with frequency loss (FL) and increased dynamic amplitude ratio (DAR) in vibration. LCPs with the least FL and maximum DAR are more stable. Further, LCP with flyash (FLCP) is highly unstable with 18.5% FL for 10% moving load and GLCP (LCP with graphene) is the most stable (6% loss). Meanwhile, the DAR for GLCP is maximum (16.13%) at 140 m/s critical velocity of moving mass. Increasing the Pasternak co-efficient increases foundation stiffness and frequency whereas Winkler’s parameter has a negligible effect. The foundation without damping oscillates more critically (with a maximized DAR of 1.92) in comparison to the foundation with a damping ratio of 0.1 (DAR of 1.17).

Analysis of thermal residual deformation using different FVFs for each ply

The thermal stresses and residual deformations in composite materials are caused by differences in the thermal expansion coefficients between the fiber and matrix, chemical shrinkage of the matrix, and temperature distribution during curing. Complex thermal stresses can cause residual thermal deformations, including spring-in, spring-out, and warpage. Consequently, modifying composite molds is time-consuming and labor-intensive.In this study, composite laminate plates were fabricated using the VARTM and VIP processes. For each ply, thermal deformation analysis using different FVFs was performed, and the results were compared with the experimental results. The analysis error of the thermal residual deformations using various FVF for each ply was 9.9–36.1%, which was lower than that using the uniform FVF for all plies. Additionally, the residual thermal deformations caused by the VIP process were smaller than those caused by the VARTM process.

A geometrically nonlinear Hellinger–Reissner shell element for the postbuckling analysis of variable stiffness composite laminate structures

Variable stiffness (VS) composite laminates provide larger freedom to design thin-walled structures than constant stiffness (CS) composite laminates. They showed to allow the redistributing of stresses, improving buckling and post-buckling performance and, therefore, reducing material weight and costs. This work extends a recently developed mixed shell element, MISS-4C, to the postbuckling analysis of VS composite laminate structures. MISS-4C has a linear elastic closed-form solution for the stress interpolation of symmetric composite materials. Its stress field interpolation is obtained by the minimum number of parameters, making it an isostatic element. Moreover, its kinematic is only assumed along its contour, leading to an efficient evaluation of all operators obtained through analytical integration along the element contour. MISS-4C uses a corotational approach within a fast multi-modal Koiter algorithm to efficiently obtain the initial post-buckling response of VS composite laminate structures.First, the element performance is investigated by analysing a carbon fibre VS composite laminate plate subjected to compressive stresses. Numerical results obtained with MISS-4C are compared with those obtained with the MISS-4 element, showing good accuracy and a high convergence rate. Subsequently, the structural response of a glass fibre VS composite laminate girder of a short-length bridge is optimised through a multi-objective optimisation that exploits the robustness of the MISS-4C element and the efficiency of the multi-modal Koiter algorithm.

Delamination and crack detection and localization of a laminated composite plate structure using regression and regression-based neural network methods

Despite significant progress, a comprehensive analysis of Machine learning algorithms for detecting delamination and crack damage in composite laminate plates is noticeably absent in the literature. This study aims to bridge this gap by meticulously help spectrum of six regression algorithms. By utilizing simulated displacement-time responses from a 16-layer laminated composite plate structure subjected to a random force, a robust dataset is constructed to evaluate the efficacy of these machine learning paradigms. Performance assessments rely on critical metrics: coefficient of determination (R2), mean absolute error (MAE), root mean squared error (RMSE), and mean absolute percentage error (MAPE).

VERIFICATION OF LAMINATE COMPOSITEPLATE SIMULATION UNDER COMBINED LOADINGS THERMALSTRESSES

This study deals with thermal cyclic loading phenomena of plates which were fabricated from composite materials (woven roving fiber glass + polyester) were exposed to (75 C°) temperature gradient thermal shock for ten times in different stage of conditioning times due to the effect of thermal fatigue using the method of Levy solution and compared these results with both results from experimental published work and (ANSYS Ver. 9) program. A composite laminate plate with fiber volume fraction (υf =25.076%) is selected in this study and applying the combined loadings like bending moment (Mo), and in-plane force (Nxx) beside the effect of thermal fatigue. It involves multi theoretical and finite element fields; but the theoretical one contains the derived equation of stresses distribution and evaluating the normal deflection of a middle point for dynamic analysis applying different boundary conditions for heating and cooling. The main present numerical results for a composite plate with (80%) fiber volume fraction claim that the relative reduction in normal deflection and dynamic load factor are (78.593%) and (9.421%) during cooling to (-15 respectively.

Comprehensive analysis of bio-inspired laminated composites plates using a quasi-3D theory and higher order FE models

A comprehensive study is carried out by employing various finite element models (FEMs) for the bending, buckling stability and free vibration analyses of bio-inspired helicoidal composite plates with various lamination schemes. A higher order quasi-3D kinematic plate theory is developed to include a shear deformation effect. The variational formulation of the problem is exploited to derive the equations of motion, element stiffness, geometrical stiffness, and mass matrices based on a non-conforming rectangular element. Three different finite elements models are derived based on non-conforming elements with different number of nodes and degree of freedom. The developed finite element model has been validated with those found in the open literature. The effects of boundary condition, lamination scheme, orthotropy ratio and aspect ratio on the mechanical response of the bio-inspired helicoidal composite plates are examined. Notably, for the lamination schemes investigated in this study, no shear locking phenomenon was observed in the analyses conducted using these FEMs. Dimensionless centre deflections, critical buckling loads and fundamental frequencies of bio-inspired helicoidal composite plates vary depending on the type of lamination scheme, boundary condition and aspect ratio. The new orientation schemes can replace the traditional ones to overcome the shear singularity and overcome the delamination defects.

Analysis of multiple high-velocity impact phenomenon in composite laminate plates

Analysis of multiple high-velocity impact phenomenon in composite laminate plates

The Effect of Layer Orientation on the Behaviour of the Multilayered Composite Plates

In recent years, the composite materials have been increasingly used in various industries. The required knowledge, which is necessary in order to be able to use composite materials, composite structural elements, requires FEM numerical simulations. In this paper, the study of the effect of the layer orientation on the behavior of the multilayered composite plates is study by taking the three-layer laminate composite for different type of laminates with different symmetric and unsymmetric orientation of the lamina: 0/90/0, 90/0/90, 45/-45/45, -45/45/-45, 0/45/90, 0/-45/90, 90/45/0, 90/-45/0. Based on the obtained results, it can state that the emergence of displacements is dependent on the ply orientation. The used models do not give the same results of the maximum values of the vertical displacement of the layered laminate composite plates.

Investigation of Different Features for Baseline-Free RAPID Damage-Imaging Algorithm Using Guided Waves Applied to Metallic and Composite Plates

In guided-wave-based damage-imaging algorithms, damage reconstruction typically involves comparing the signals with and without a defect. However, in many cases, defect-free data may not be available. Therefore, in this study, baseline and baseline-free approaches were used for damage imaging, exploiting not only the amplitude of the signal as the feature but also five additional features, namely, the amplitude of the sparse signal after deconvolution, the amplitude of the coefficients at the excitation frequency from the re-assigned short-time Fourier transform, the time of flight determined from cross-correlation, kurtosis in the time domain, and kurtosis in the frequency domain. For this study, three different plates with different types of defects were considered: a metallic plate with a notch-type artificial defect, a pultruded type of composite plate with an impact defect, and a laminate composite plate with plexiglass serving as an added mass damper artificial defect. The Reconstruction Algorithm for Probabilistic Inspection of Damage (the RAPID algorithm) was used to characterize the defects on the three plates, and the defect parameters were then quantified by creating an ellipse after thresholding.

Optimization of a structural Acoustic Black Hole embedded in a stringer-stiffened composite laminate panel

Many modern airframes are made of composite laminate materials due to their low mass but strong loadbearing capability. Carbon fiber composite laminates allow for a strong and lightweight aircraft, but create unhealthy levels of disruptive and uncomfortable noise within the fuselage. This work looks at the possibility of a structural Acoustic Black Hole (ABH) as a passive vibration damping solution for a common stringer-stiffened airframe panel. A 1-D symmetrically damped ABH was integrated vertically into the cross section of a stringer stiffener of a composite laminate plate. A multi-objective evolutionary algorithm was employed to search for the optimal ABH dimensions in terms of the tradeoff between weight, axial linear buckling load, and integrated vibration response. Computational results predicted the ability for damped ABH-stiffeners of a certain dimension to have less vibrational response than others with comparable linear density and axial strength. Mass normalized, non-tapered and ABH-tapered preliminary panels were manufactured and tested. These results showed a capability of ABH stiffeners to decrease vibrational response in the attached skin, more prominently above their cut-on frequency. Stiffened panels were manufactured to optimized specifications and their experimental results validate the presence of an optimal ABH dimension to achieve passive vibration damping in a system with mass and structural constraints.

Experimental and numerical analysis of residual compression strength after Low-Velocity Impact of carbon/epoxy composite plate

A composite laminate is susceptible to Low-Velocity Impact (LVI) load, leading to Barely Visible Impact Damage (BVID) accompanied by invisible damage in the form of delamination. Such delamination is significantly reduced the compression strength of the composite laminate plate. The present work provides an experimental and numerical analysis, based on finite elements, on residual compression strength after the low-velocity impact of carbon/epoxy composite plate. Five specimens of 16 layers Unidirectional carbon/epoxy composite plate with fiber orientation [+450/900/-450/00/+450/900/-450/00]s have been tested subject to low-velocity impact load, with a single use of impact energy value of 2.75 Joule/mm, followed by compression test. Moreover, another similar five specimens tested compression before impact to measure its compression strength. Experimental results were observed to identify the profile and size of total-projection delamination after impact and after compression and compression-strength before and after impact. The Finite Element analysis is based on the utilization of cohesive zone elements with Benzeggagh-Kenane fracture criterion to predict the initiation and propagation of delamination, Kirchhoff based formulation of continuing shell element to model stiffness of the laminate, and Hashim-Rotem damage mechanism to predict intralaminar damages.

Fatigue strength of self-piercing riveted joints of carbon fiber reinforced composite and Al5052 alloy plates

Self-piercing riveting (SPR) is an alternative to the conventional spot-welding method when joining sheets of dissimilar materials. In this study, the static and fatigue strengths of the SPR joints of carbon fiber composite laminate and an Al5052 aluminum alloy plate under various loading conditions were evaluated. Fatigue test results show that the load amplitudes, corresponding to the fatigue endurance limit, based on a lifetime of one million cycles, were 680 N, 323 N, and 305 N for loading angles of 0°, 45° and 90°, respectively, with corresponding fatigue ratios of the joints of 33%, 23% and 24%. The fatigue strengths at the loading angles of 45°, and 90° in terms of the equivalent stress intensity factor were found to be much higher than those at a loading angle of 0°. This is partially due to the difference in the fatigue failure modes. Regarding the fatigue strength designs of SPR joints consisting of composite laminate and aluminum alloy plates under various loads, it can be suggested that the tensile-shear strengths dominate the SPR fatigue strengths of the joints because they are highly vulnerable to tensile-shear loading.

Free flexural vibration of cracked composite laminated plate using higher-order XFEM

In this work, a higher-order XFEM approach is presented and implemented to analyze free flexural vibration in cracked composite laminated plate using higher-order shear deformation theory. The composite laminated plate experiences flexural vibration during its service life due to transverse shear loading. Out-of-plane modulus of the plate is much lesser than the in-plane modulus, so the free vibration study of the plate has become a crucial parameter for a safe service environment. The proposed methodology introduce higher-order tip enrichment functions (r2 terms) for crack simulation in laminated plate. These enrichment functions efficiently capture all conceivable displacements and rotations near the crack tip region. A comparative analysis between higher-order XFEM and conventional XFEM approach is presented in terms of computational accuracy. Several numerical examples are presented to demonstrate the accuracy of these higher-order enrichment functions, which contain variations in natural frequency with respect to crack sizes for different symmetric ply composite laminate plates under varied boundary conditions. The numerical results demonstrate that the proposed higher-order XFEM approach is significantly enhancing computational accuracy than the classical XFEM approach.

Free Vibration Analysis of Functionally Graded Graphene-Reinforced Composite-Laminated Plates

Graphene is recognized as one of the most alluring reinforcements for composite materials due to its exceptional mechanical capabilities. However, the existing models disregarding the compatible requirements of interlaminar stresses in the literature may meet severe challenges for the dynamic analysis of functionally graded graphene-reinforced composite (FG-GRC) laminated thick plates. If transverse shear deformations cannot be described accurately, the prediction of natural frequencies for FG-GRC laminated plates will be seriously and directly affected. Accordingly, an attractive plate theory in conjunction with the analytical approach and finite-element formulation is proposed for free vibration analysis of FG-GRC plates. An improved transverse shear stress field is acquired in terms of the three-dimensional (3D) elasticity equations and the Reissner mixed variational theorem (RMVT). The performance of the suggested model was evaluated using 3D elasticity solutions and the results obtained from other models. Numerical results showed that the suggested model can produce promising results for the thick laminated and sandwich plates. Additionally, a thorough investigation was conducted to study the effects of several graphene parameters, including volume fractions, distribution patterns, span-to-thickness ratios, aspect ratios, boundary conditions, and stacking sequences, on the dynamic responses of FG-GRC laminated plates.

Numerical simulation of inductive heating in thermoplastic unidirectional cross-ply laminates

Thermoplastic Composites can be re-melted allowing them to be joined via welding. This is an attractive alternative to conventional methods that are used to join thermoset composite parts such as mechanical fastening and adhesive bonding. In this work the inductive heating of uni-directional (UD) plies of thermoplastic carbon fiber reinforced polymer (CFRP) laminates is investigated. The focus is on developing a numerical electromagnetic and thermal simulation model that captures the main processes involved in eddy current generation and heat generation, in particular in the interface areas of the UD plies. A measurement technique has been developed to obtain the electric properties of the ply material. Furthermore, to support the modelling of both the induction heating equipment and work piece a field measurement of the magnetic field surrounding the coil and work piece has been developed. Inductive heating experiments were carried out on several thick composite laminate plates with different ply lay-ups to compare and validate the electro-magnetic-thermal simulation model. The measured surface temperatures were compared with the results from the simulation model. The results of this work can be used to support the design of UD-ply laminates to improve their ability to be welded via inductive heating. In addition, the results of this work can be used to assist in pre-determining induction welding equipment settings and heating times.

Delamination damage imaging method of CFRP composite laminate plates based on the sensitive guided wave mode

Delamination damage imaging method of CFRP composite laminate plates based on the sensitive guided wave mode

Development of analytical and FEM solutions for static and dynamic analysis of smart piezoelectric laminated composite plates on elastic foundation

This paper proposes new analytical and finite element solutions for studying the effects of elastic foundations on the uncontrolled and controlled static and vibration responses of smart multi-layered laminated composite plates with integrated piezoelectric layers, acting as actuators and sensors. A non-polynomial higher-order plate theory with zigzag kinematics involving a trigonometric function and a local segmented zigzag function is adopted for the first time for modeling the deformation of a smart piezoelectric laminated composite plate supported on an elastic foundation. This model has only five independent primary variables like that of the first-order shear deformation theory, yet it considers the realistic parabolic behavior of the transverse shear stresses across the thickness of the laminated composites plates, and also maintains the continuity conditions of transverse shear stresses at the interfaces of the laminated plates. A two-parameter foundation model, namely Pasternak’s foundation, is used to model the deformation and shear interactions of the elastic foundation. The governing set of equations is derived by implementing Hamilton’s principle and variational calculus. Two different solution methods, namely, a generalized closed-form analytical solution of Navier-type, and a C0 isoparametric finite element (FE) formulation, are developed for solving the governing set of equations. The solutions in the time domain are obtained with Newmark’s average acceleration method. Comprehensive parametric studies are presented to investigate the influence of elastic foundation parameters, piezoelectric layers, loading, and boundary conditions on the static and dynamic responses of the smart composite plates with piezoelectric layers. The effects of the elastic foundations on the vibration control of the smart composite plates are also presented by coupling the piezoelectric actuator and sensor with a feedback controller. Several benchmark results are presented to show the influence of the various material and geometrical parameters on the controlled and uncontrolled responses of the smart plates, and also the significant effect of the elastic foundations on the static and dynamic responses of the smart structures. The results obtained are in very good agreement with the available literature, and it can be concluded that the proposed analytical solution and FE formulation can be efficiently used to model the static and dynamic electro-elastic behavior of smart laminated plates supported on elastic foundations.

Quantitative identification of damage in composite structures using sparse sensor arrays and multi-domain-feature fusion of guided waves

Damage detection techniques using Lamb waves have shown excellent capabilities in the diagnosis of composite structures. However, structural health monitoring of composite structures is challenging, especially for damage classification. This study proposes a machine learning-based method with a sparse sensor array to achieve quantitative classification of the damage location and severity on a composite plate. First, multi features extraction is used to construct a support vector machine (SVM) damage localization model. Second, optimal path extraction combined with principal component analysis (PCA) is used to construct an SVM model for classification. To reduce the operational burden of structures, the sparse array is employed. To improve the damage classification accuracy, Fisher clustering is proposed to extract the optimal detection path. Then, PCA is used to achieve data fusion. Experimental results on a glass fiber-reinforced epoxy composite laminate plate demonstrate that the proposed technique can accurately locate and classify the quantitative artificial damage.

Isogeometric analysis of stress concentrations and failure strength in composite plates with circular holes using RHT-splines

This paper studies the stress concentration factors (SCFs) to predict the first ply failure (FPF) of cross and angle-ply laminate composite plates with single circular holes. The rational splines over hierarchical T-meshes (RHT-splines) were chosen as a surface design methodology for Isogeometric Analysis (IGA) due to their ability to exactly represent the geometry, efficient and simple local refinement algorithm, and reduction of the superfluous control points of the NURBS surface. The Bézier extraction concept was used as an element structure for IGA that allows mapping the Bernstein polynomials basis functions on Bezier elements to be performed on RHT-splines geometries. Several failure criteria and composite materials are employed in numerical examples for different fiber orientation angles through Matlab® implementation. The results obtained by the IGA based on RHT-splines showed very good conformity with those obtained by the analytic approach and finite element method (FEM) published in the literature, which demonstrates the robustness and accuracy of the IGA using RHT-splines and provides an effective and realistic way to determine SCF and failure strength. The Matlab® program for the analytical approach and failure theories is made an open-source and can be downloaded from (Github Website).

Enhancing the control of boron epoxy cross-ply laminated composite plates through intelligent implementation of PZT sensor and actuator

Piezoelectric materials find diverse applications in structural engineering, particularly in fields like condition monitoring, smart control, and testing. The captivating interplay between their mechanical and electrical properties has garnered significant attention, showcasing immense potential for practical utility. Notably, these materials boast costeffectiveness, lightweight characteristics, compact size, exceptional dynamic capabilities, swift responsiveness, enduring stability, and remarkable energy conversion efficiency. In our research initiative, we delve into a study concentrated on the symmetric surface attachment of two piezoelectric patches or actuators onto composite laminate plates. The goal is to induce a bending effect in the laminate by applying equal-magnitude electric voltages with opposite polarities to these symmetrically positioned piezoelectric actuators. The determination of the bending moment involves the application of principles related to elasticity and piezoelectricity. To scrutinize the displacement and natural frequency of the composite plate influenced by this bending moment, we utilize plate theory and derive analytical solutions. Furthermore, these piezoelectric patches, affixed to the composite laminate plate's surface, double as vibration actuators. We subject the plate to loads to investigate its vibration response in a simply supported rectangular configuration. This excitation is achieved by applying time-harmonic voltages to the piezoelectric patches. Throughout our study, we compute analytical solutions for both deflection and vibration amplitude, presenting numerical results that depict the static deflection and vibration amplitude of the plate. Additionally, a parametric study is conducted to elucidate the influence of piezoelectric actuator size and placement on cross-ply composite laminate plates.