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We examine the detection and response characteristics of giant magnetostrictive/piezoelectric laminated cantilevers under cyclic bending in a combined numerical and experimental approach. The laminate is fabricated using thin Terfenol-D and PZT layers. Three-dimensional finite element analysis was conducted, and the dynamic electromagneto-mechanical fields in the two-layered magnetostrictive/piezoelectric laminate were predicted by introducing a second-order magnetoelastic constant of Terfenol-D. The tip deflection, induced voltage, and induced magnetic field were also measured, and experimental data were compared with numerical simulations to verify the model. The effects of load ratio and frequency on the dynamic electromagneto-mechanical fields were then discussed in detail. The finite element method is shown to be capable of estimating the dynamic electromagneto-mechanical fields in the giant magnetostrictive/piezoelectric laminated cantilevers, making it a useful tool for designing future electronic devices with self-sensing or energy harvesting capabilities. [ABSTRACT FROM AUTHOR]

This paper presents the nonlinear electromagneto-mechanical behavior of magnetostrictive/piezoelectric laminates under three-point bending both numerically and experimentally. The laminates are fabricated using thin Terfenol-D and PZT layers. The three-point bending test was conducted on the Terfenol-D/PZT laminates, and the displacement, induced magnetic field and induced voltage due to mechanical loads were measured. Three-dimensional finite element analysis was also carried out, and the electromagneto-mechanical fields in the laminates were predicted by introducing a second-order magnetoelastic constant for Terfenol-D. Comparison was then made between simulation and experiment. [ABSTRACT FROM PUBLISHER]

Abstract: We examine the nonlinear electromechanical response of piezoelectric mirrors driven by PZT thick films in a combined numerical and experimental investigation. First, some electromechanical tests were performed to measure the response (displacement versus load, displacement versus electric field) of the PZT thick films on elastic layers. A finite element analysis was then employed to determine the material properties in the PZT thick films using measured data. Next, the mirror tilt angle and electromechanical field concentrations due to electrodes in piezoelectric mirrors under electric fields were analyzed by introducing a model for polarization switching in local areas, and a nonlinear behavior was discussed in detail. The mirrors consisted of four fully or partially poled PZT unimorphs. Test results on the mirror tilt angle versus electric field, which verify the model, were also presented. [Copyright &y& Elsevier]

Abstract: This paper examines the nonlinear electromechanical response of 1-3 piezoelectric/polymer composites. The piezocomposites contain square or circular piezoelectric rods in an epoxy matrix. Experiments were conducted to measure the displacement versus electric field curves, using the device specimen of the 1-3 piezocomposites. Three dimensional finite element analysis was also carried out to study the electromechanical fields in the 1-3 piezocomposites by introducing a model for polarization switching. Comparison was then made between simulation and experiment. [Copyright &y& Elsevier]

This article discusses the delayed fracture and localized polarization switching near a crack tip in three-point bending piezoceramics under electromechanical loading. We have used finite element analysis to study delayed fracture experiments with single-edge precracked-beam method. A nonlinear finite element analysis was employed to calculate the fracture mechanics parameters such as energy release rate for the permeable, impermeable, and open crack face boundary conditions. Recent proposed energetically consistent boundary conditions were also considered. The effects of applied electric field and localized polarization switching on the fracture mechanics parameters were then examined. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to investigate the effect of magnetic field on the fatigue crack growth behavior of nickel iron soft ferromagnetic materials under Mode I loading. Fatigue crack growth tests were conducted using single-edge cracked tension specimens in a magnetic field, and the effects of magnetic field and loading condition on the crack growth rates were examined. Magnetic field effect on the stress intensity factor range also was discussed for a single-edge cracked soft ferromagnetic strip. The fracture surfaces were examined by scanning electron microscopy to correlate with fatigue characteristics. [ABSTRACT FROM AUTHOR]

Abstract: The static electromechanical displacement and polarization switching properties of piezoelectric laminated actuators under three point bending have been investigated theoretically, numerically and experimentally. A laminated beam theory is expanded to allow for piezoelectric/metal/piezoelectric actuator, and the effects of electromechanical loading on the displacements of the actuators are analyzed. A nonlinear three-dimensional finite element procedure which allows to compute the polarization switching behavior is also proposed. Three point bending tests are used to validate the numerical predictions, using laminated actuators made with thin soft lead zirconate titanate (PZT) piezoelectric layers and a thin metal sheet, and comparison is made between numerical results and experimental data. [Copyright &y& Elsevier]

Cellulose nanofiber (CNF) has been accepted as a valid nanofiller that can improve the mechanical properties of composite materials by mechanical and chemical methods. The purpose of this work is to numerically and experimentally evaluate the mechanical behavior of CNF-reinforced polymer composites under tensile loading. Finite element analysis (FEA) was conducted using a model for the representative volume element of CNF/epoxy composites to determine the effective Young's modulus and the stress state within the composites. The possible random orientation of the CNFs was considered in the finite element model. Tensile tests were also conducted on the CNF/epoxy composites to identify the effect of CNFs on their tensile behavior. The numerical findings were then correlated with the test results. The present randomly oriented CNF/epoxy composite model provides a means for exploring the property interactions across different length scales. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the experimental and numerical characterization of the interlaminar shear failure of hybrid composite laminates at cryogenic temperatures. Cryogenic short beam shear tests were performed on hybrid laminates consisting of woven glass fiber reinforced polymer (GFRP) composites and polyimide films to evaluate their interlaminar shear strength. Microscopic observations of damage accumulation and failure mechanisms were also made on failed specimens. In addition, a progressive damage analysis was conducted to predict the initiation and growth of damage in the specimens, and the interlaminar shear strength was determined from the maximum shear stress in the failure region. The damage effect on the interlaminar shear properties of hybrid laminates at cryogenic temperatures was examined based on the experimental and numerical results. [ABSTRACT FROM AUTHOR]