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The purpose of the study is to present a frequency domain spectral finite element model (SFEM) based on fast Fourier transform (FFT) for wave propagation analysis of smart laminated composite beams with embedded delamination. For generating and sensing high-frequency elastic waves in composite beams, piezoelectric materials such as lead zirconate titanate (PZT) are used because they can act as both actuators and sensors. The present model is used to investigate the effects of parametric variation of delamination configuration on the propagation of fundamental anti-symmetric wave mode in piezoelectric composite beams.

The spectral element is derived from the exact solution of the governing equation of motion in frequency domain, obtained through fast Fourier transformation of the time domain equation. The beam is divided into two sublaminates (delamination region) and two base laminates (integral regions). The delamination region is modeled by assuming constant and continuous cross-sectional rotation at the interfaces between the base laminate and sublaminates. The governing differential equation of motion for delaminated composite beam with piezoelectric lamina is obtained using Hamilton’s principle by introducing an electrical potential function.

A detailed study of the wave response at the sensor shows that the A0 mode can be used for delamination detection in a wide region and is more suitable for detecting small delamination. It is observed that the amplitude and time of arrival of the reflected A0 wave from a delamination are strongly dependent on the size, position of the delamination and the stacking sequence. The degraded material properties because of the loss of stiffness and density in damaged area differently alter the S0 and A0 wave response and the group speed. The present method provides a potential technique for researchers to accurately model delaminations in piezoelectric composite beam structures. The delamination position can be identified if the time of flight of a reflected wave from delamination and the wave propagation speed of A0 (or S0) mode is known.

Spectral finite element modeling of delaminated composite beams with piezoelectric layers has not been reported in the literature yet. The spectral element developed is validated by comparing the present results with those available in the literature. The spectral element developed is then used to investigate the wave propagation characteristics and interaction with delamination in the piezoelectric composite beam.

To investigate the large amplitude free flexural vibration of doubly curved shallow shells in the presence of cutouts.

Finite element model using an eight‐noded C⁰ continuity, isoparametric quadrilateral element is employed. Nonlinear strains of von Karman type are incorporated into the first‐order shear deformation theory.

Cylindrical shell shows mostly hard spring behavior whereas spherical shell shows both hard spring and soft spring behavior with the increase of amplitude ratios for different cutout sizes, radii of curvature and thickness parameters. At a particular value of the amplitude ratio, the frequency ratio of shells is governed by the interactive effects of stiffness and mass.

Aircraft, spacecraft and many other structures where shell panels are used, undergo large amplitude nonlinear vibrations.

The paper will assist researchers of vibration behavior of elastic systems.

The purpose of this paper is to study the nonlinear forced vibration responses of delaminated composite shells in hygrothermal environments.

Finite element method using an eight-noded C0 continuity, isoparametric quadrilateral element is employed. The theoretical formulations are based on the first order shear deformation theory and von Kármán type nonlinear kinematics. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code.

The effect of delaminations on the nonlinear transient response of delaminated composite shells is dependent not only on the size but also on the location of the delaminations and hygrothermal environments.

The present study is limited to cylindrical and spherical shells having rectangular planform containing single delamination. Studies on different shell forms having non rectangular planforms containing multiple delaminations can be taken up for future research.

Nonlinear transient response of delaminated shells in hygrothermal environments is studied for the first time. It will assist researchers of nonlinear dynamic behavior of elastic systems.

The purpose of this paper is to study the nonlinear forced vibration response of delaminated composite shells in hygrothermal environments.

Finite element method using an eight‐noded C⁰ continuity, isoparametric quadrilateral element is employed. The theoretical formulations are based on the first‐order shear deformation theory and von Kármán type nonlinear kinematics. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code.

The paper finds that the effect of presence of delaminations on the nonlinear transient response of composite shells is dependent not only on the size, but also on the location of the delaminations and the hygrothermal environments.

The present study is limited to cylindrical and spherical shells having rectangular planform containing single delamination. Studies on different shell forms having non‐rectangular planforms containing multiple delaminations can be taken up for future research.

The value in this paper lies in that nonlinear transient response of delaminated shells in hygrothermal environments is studied for the first time. It will assist researchers of nonlinear dynamic behavior of elastic systems.