Anup Ghosh

ACTIVE VIBRATION CONTROL OF COMPOSITE PLATE USING AFC ACTUATOR AND PVDF SENSOR

A finite element formulation for active vibration control of laminated composite plate integrated with active fiber composite (AFC) layer acting as distributed actuator and PVDF layer as sensor is presented in this paper. An eight noded quadratic isoparametric element with five mechanical degrees of freedom and one electrical degree of freedom per node of the element is considered. Newmark time integration method is used to calculate the dynamic response and negative velocity feedback control algorithm is used to control the dynamic response of the laminated composite plate. The effect of piezoelectric fiber orientation in actuator layer on the control of vibration is studied.

Active Control of Geometrically Non-linear Transient Response of Smart Laminated Composite Plate Integrated With AFC Actuator and PVDF Sensor

A coupled electromechanical finite element formulation for active control of geometrically non-linear transient response of laminated composite plate is studied. First-order shear deformation theory and von Karman type non-linear strain displacements are used. The plate is discritized using eight-noded quadratic isoparametric elements with five mechanical degrees of freedom and one electrical degree of freedom per node. Newton-Raphson iterative method in association with Newmark time integration method is used to solve the non-linear finite element equilibrium equation. Negative velocity feedback control algorithm is used to control the dynamic response of the smart laminated composite plate. AFC layer poled in fiber direction acting as distributed actuator and PVDF layer poled in thickness direction acting as sensor are considered. This study involves two types of actuator sensor arrangements: (1) the substrate is sandwiched between AFC actuator and PVDF sensor, called non-collocated arrangement and (2) AFC actuator and PVDF sensor are placed on top of the substrate, called collocated arrangement. The effect of piezoelectric fiber orientation in actuator layer on vibration control for both cross-ply and angle-ply laminates are examined.

Hygrothermal effects on the initiation and propagation of damage in composite shells

Purpose – The aim of this paper is to investigate the initiation and progress of damage in laminated composite shells at elevated moisture concentration and temperature due to low‐velocity impacts.Design/methodology/approach – A finite element analysis procedure is developed to investigate the initiation and propagation of damage in laminated composite shells in hygrothermal environments.Findings – It was found inter alia, that in the case of rise of temperature present FEM results match well with closed form solutions and that stress results at different levels of moisture concentration agree with the results published in the open literature.Practical implications – The paper provides in‐depth insight into the progress of damage in laminated shell structures.Originality/value – The paper investigates initiation and progress of damage in laminated composite shell structures due to low‐velocity impacts.

Dynamic and impact response of damaged laminated composite plates

In the present investigation, a finite element analysis procedure is developed to predict the initiation and propagation of damages as well as to analyse damaged laminated composite plates under forced vibration and impact loads. Isoparametric quadratic plate bending element (nine‐noded rectangular) based on Mindlin plate theory is used to develop the FE codes for the present analysis. A phenomenological damage model assuming the effective stress concept is used to represent the damage of a lamina. The initiation and progress of damage due to forced vibration and low velocity impact are studied for different impactor velocities.

Initiation and propagation of damage in laminated composite shells due to low velocity impact

Abstract A finite element analysis procedure is developed to investigate the initiation and propagation of damage in laminated composite shells, using a Continuum Damage Mechanics (CDM) model. A phenomenological damage model assuming the effective stress concept is introduced with a fourth order damage tensor to model the damage in a lamina. A nine nodded isoparametric shell element based on the first order shear deformation theory is used to develop the finite element analysis procedure. The initiation and progress of damage, variation of contact force and displacement in a spherical shell due to low velocity impact are studied for different impactor velocities.

Geometrically Non-Linear Bending Analysis of Piezoelectric Fiber-Reinforced Composite (MFC/AFC) Cross-Ply Plate Under Hygrothermal Environment

A finite element formulation for geometrically non-linear bending behavior of smart structures integrated with piezoelectric fiber-reinforced composite (AFC/MFC) layer acting as distributed actuator is presented in this article. The formulation of this hygro-thermo-electro-mechanical coupled problem is based on the first-order shear deformation theory (FSDT) and the von Kármán type geometric non-linearity. Resulting non-linear algebraic governing equations are linearized by Newton–Raphson iterative method. A developed finite element formulation is initially solved for validation and comparison with existing results. A wide variety of numerical examples considering cross-ply laminated substrates subjected to combined mechanical, hygrothermal and electrical loads are presented. The effect of piezoelectric fiber orientation in an actuator to counteract non-linear deflections is analyzed.

Active Control of Geometrically Nonlinear Transient Response of Smart Laminated Composite Plate Integrated With AFC Actuator and PVDF Sensor

A coupled electromechanical finite element formulation for active control of geometrically nonlinear transient response of laminated composite plate is studied. First order shear deformation theory and Von Karman type nonlinear strain displacements are used. The plate is discritised using eight noded quadratic isoparametric elements with five mechanical degrees of freedom and one electrical degree of freedom per node. Newton-Raphson iterative method in association with Newmark time integration method is used to solve the nonlinear finite element equilibrium equation. Negative velocity feedback control algorithm is used to control the dynamic response of the smart laminated composite plate. Active fiber composite (AFC) layer poled in fiber direction acting as distributed actuator and PVDF layer poled in thickness direction acting as sensor are considered. Present study involves two types of actuator sensor arrangements. Case I: the substrate is sandwiched between AFC actuator and PVDF sensor. Case II: AFC actuator and PVDF sensor are collocated on top of the substrate. The effect of piezoelectric fiber orientation in actuator layer on vibration control for both cross ply and angle ply laminates are examined.Copyright

Fatigue life estimation and crack propagation analysis of orthotropic lamina using XIGA methodology

ABSTRACT In the present work, a NURBS-based Extended Isogeometric Analysis (XIGA) code has been developed for fracture analysis of orthotropic lamina. The XIGA code is capable of an efficient analysis of crack problems using non-uniform rational B-spline basis functions for both the solution field and geometric description of model. The level set approach is used to track the crack geometry. Crack faces are enriched by Heaviside enrichment function and crack tip singularity is captured by asymptotic crack tip enrichment functions. The interaction integral (M-Integral) method is used to calculate mixed mode stress intensity factor for further stable crack growth. The Paris crack growth law is used to simulate the crack propagation and fatigue life estimation in orthotropic media using life cycle increment approach. The developed code has been validated for static and fatigue analysis. The effect of varying angle of orthotropy on fatigue life of 2D plate is investigated using XIGA methodology leading to an optimized ply orientation of orthotropic plate.