Uncertainty Quantification of Composite Laminate Damage with the Generalized Information Theory

Modern composite armor plate is generally composed of faceplate with high hardness and backplate with good toughness. 45 steel/60Si2CrA multilayer composite casting blank with 11 layers, containing 60Si2CrA steel as faceplate and 45 steel as backplate, was fabricated by composite casting. The deformation and heat treatment process of 45steel/60Si2CrA multilayer composite plate were studied. The results show that the interfaces between faceplate and backplate have good combination and the thickness of each layer is basic uniform by reasonable deformation distribution. Yield and tensile strength of the composite plate reaches 956MPa and 1018MPa, the hardness of 45 steel layer and 60Si2CrA layer is 448HV and 536HV respectively after the heat treatment of 860°C water quenching+ high temperature tempering. The mechanical properties meet the qualification of armor plate. The bulletproof test displays that 45 steel/60Si2CrA multilayer composite armor plate can prevent the breakthrough of DAP51B type bullet with the velocity of 500m/s.

C0 triangular elements based on the Refined Zigzag Theory for multilayer composite and sandwich plates

The effectiveness of wavelet transform in detecting delamination damages in multilayered composite beams and plates is studied here. The damaged composite beams and plates are modeled in finite element software ABAQUS and the first few mode shapes are obtained. The mode shapes of the damaged structures are then wavelet transformed. It is observed that the distribution of wavelet coefficients can identify the damage location of beams and plates by showing higher values of wavelet coefficients at the position of damage. The effectiveness of the method is studied for different boundary conditions, damage location and size for single as well as multiple delaminations in composite beams and plates. It is observed that both discrete wavelet transform (DWT) and continuous wavelet transform (CWT) can detect the presence and location of the damaged region from the mode shapes of the structures. DWT may be used to approximately evaluate the size of the delamination area, whereas, CWT is efficient to detect smaller delamination areas in composites.

This paper presents an analytical approach to postbuckling behaviors of functionally graded multilayer nanocomposite plates reinforced by a low content of graphene platelets (GPLs) using the first order shear deformation theory, stress function and von Karman-type nonlinear kinematics and include the effect of an initial geometric imperfection. The weight fraction of GPL nano fillers is assumed to be constant in each individual GPL-reinforced composite (GPLRC). The modified Halpin-Tsai micromechanics model that takes into account the GPL geometry effect is adopted to estimate the effective Young’s modulus of GPLRC layers. The plate is assumed to resting on Pasternak foundation model and subjected to mechanical and thermal loads. The results show the influences of the GPL distribution pattern, weight fraction, geometry, elastic foundations, mechanical and temperature loads on the postbuckling behaviors of FG multilayer GPLRC plates.
 Keywords: Postbuckling; Graphene nanocomposite plate; First order shear deformation plate theory.
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Advanced and refined variable-kinematics plate theories built with a hierarchical approach in an extended framework of Carrera's unified formulation (CUF) are combined with Ritz and Galerkin methods to deal with a thermo-mechanical buckling analysis of anisotropic multilayered composite and sandwich plates. Buckling interaction curves and stability envelopes for different thermal and mechanical loading combinations are presented. The influence of the kinematics description and the expansion orders upon the results accuracy is evaluated. The effect of the transverse normal deformation on critical temperature parameters is thoroughly investigated. Convergence and results accuracy are discussed.

The paper presents a mechanical analysis of the multi-layer circular composite plate For MEMS devices. Each layer of the plate is assumed to have different radius, material properties and initial stresses. Governing equations for the composite plate are derived based on the classical laminated plate theory, and analytical soultions have been developed for static deflection of the initially stressed plate due to transverse pressure loading as well as for a given electric field in the piezoelectric layer. A nonlinear finite elernent analysis of the plate is also performed. The analytical result match the FE results for the range of parameters used in the microphone design. The analytical model will be useful in the design and optimization of MEMS devices containing circular piezoelectric composite plates and diaphragms.

This research presents results obtained from numerical analysis of a circular composite plate under impact of drop hammer and internal pressure load simultaneously. Influence of reinforced orientationangles of the multi-layer composite plate with fixed boundary conditions on displacements and axial stresses along the radius direction was studied. Employing ABAQUS software results for reinforcedorientation angles of [0/90/0]s, [0/45/60]s, [0/45/90]s, [0/30/60]s, [0/30/75]s, [0/15/30/60/75/90],[0/45/90/90/-45/0] are compared. Finding indicated that the reinforcedorientation angles have considerable effect on the axial stresses changing from compressive to tensile stresses. [0/45/90/90/-45/0]s showed the minimum displacements and axial stresses.

Two-scale analytical solutions of multilayered composite rectangular plates with in-plane small periodic structure

Hygrothermal effects on the bending of angle-ply composite plates using a sinusoidal theory

In this study, a new damage detection technique is developed so that delamination in a multilayer composite plate can be detected by comparing multi-path pitch-catch Lamb wave signals in a piezoelectric transducer network rather than by comparing each signal with its corresponding baseline signal obtained from the pristine condition. The development of the proposed technique is based on the premise that the fundamental anti-symmetric mode (A0) slows down when it passes through a delamination area while the speed of the fundamental symmetric mode (S0) is invariant. First, the delay of the A0 mode in each path is used as a delamination sensitive feature and extracted using a proposed mode extraction technique. This mode extraction technique uses dual piezoelectric transducers composed of a concentric ring and circular piezoelectric transducers, and it is capable of isolating the A0 mode in any desired frequency without frequency or transducer size tuning. Once the time delays of the A0 mode are computed for all pitch-catch paths in the transducer network, an instantaneous outlier analysis is performed on these features to identify wave propagation path(s) affected by the delaminated region(s). Because the time delays of the A0 mode are instantaneously computed from existing multiple paths, it has been demonstrated that robust delamination detection can be achieved even under varying temperature conditions.

Ballistic Performance of Multi-layered Fabric Composite Plates Impacted by Different 7.62mm Calibre Projectiles

A refined asymptotic theory and computational model for multilayered composite plates

Thermo-mechanics of undamaged and damaged multilayered composite plates: a sub-laminates finite element approach

This paper proposes a dense spray-coating active sensing arrays for composite structural health monitoring via the guided wave control. The actuation-sensing capability is realized by integrating piezoelectric nano-powder into a hosting matrix, followed by the formation of an active material layer on the composite surface through a spraying process. The actuation and sensing of guided wave mode can be achieved through the optimization of electrode configuration, in conjunction with dispersion effect. This research initiates with the analysis of the dispersion curves of composites to determine electrode parameters. Subsequently, three-dimensional numerical models in several array patterns, such as inter-digital type, comb types and irregular annular array, are meticulously constructed. Single-mode generation at one direction is achieved through the spatial distribution of array electrodes coupled with wavelength modulations in inter-digital array and comb array. At the same time, omnidirectional single-mode generation of irregular annular array is conducted through the electrode spatial distribution coupled with all direction wavelength modulations. Ultimately, the guided wave control performance is numerically investigated through exciting an anti-symmetric and a symmetric type guided wave mode in a multilayer composite plate. The numerical simulation shows that the proposed spray-coating system possesses great potential for future composite damage detection applications. The paper finishes with summary, concluding remarks, and suggestions for future work.

The use of composite materials has vastly increased in recent years. Great interest is therefore developed in the damage detection of composites using non- destructive test methods. Several approaches have been applied to obtain information about the existence and location of the faults. This paper used the vibration response of a composite plate to detect and localize delamination defect based on the modal analysis. Experiments are conducted to validate the developed model. A two-dimensional finite element model for multi-layered composites with internal delamination is established. FEM program are built for plates under different boundary conditions. Natural frequencies and modal displacements of the intact and damaged multi-layer composite plates are subsequently analyzed for various samples. Also, composite plates are made for vibration testing and analysis and to comparison of the numerical and experimental results, shows good agreement between them.