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DynaMIX Laboratory
Dynamical Systems and Multiphysical Interactions Lab
School of Mechanical Sciences
Indian Institute of Technology GOA
Research Gallery
Information about some ongoing and completed research problems.
Ambient Energy Harvesting from Nonlinear Vibrations of Smart Material Structures
Cantilevered Nonlinear Piezoelectric Harvesters - Planar Configurations
This research focusses on developing smart material-based structural configurations which can harvest ambient vibrational energy over a broadband frequency spectrum. Mechanics-based Models and Experiments are developed and responses are characterized under deterministic and random types of ambient excitations. Excitations from ambient mechanical and wind flow-induced vibration sources are considered.
Experimental capturing of period-3 intra-well subharmonic response using the facility at VEHC Lab at IIT Madras. [3,4]
Under ambient mechanical excitation
Under wind flow-induced excitation
Wind-Tunnel experiments (performed at LUT, Poland) showing the wind flow vortex-induced vibration response.
Wind flow-induced bending-torsional mode vibrations.
Nonlinear Piezoelectric Harvesters for Multidirectional Excitation - Spatial Configurations
Spatial configurations of piezoelectric harvesters designed for harvesting energy from motions resulting under multi-directional exicitation are investigated in this research. Response of a variable-length spherical pendulum-based configuration and the multi-stable axisymmetric potential-based piezoelectric harvesters are studied here.
Axisymmetric potential well-based PEH. [8]
Schematic of the spherical elastic pendulum embeded with stack-type piezoelectric harvester. [3]
Response under multidirectional excitation.
Rotational Pendulum-based Electromagnetic Harvester
(a) Schematic and (b) experimental model of rotational pendulum-based electromagnetic harvester developed at LUT, Poland.
(c) Nonlinear Torque-angular displacement characteristic and (d) tri-stable potential of the system obtained from the nonlinear magnetic-force interaction among the fixed and moving magnets. (e) Intra-well and (f) cross-well periodic responses of the electromagnetic harvester under vertical excitation. [6]
Smart Material Characterization, Sensor-Transducer Design
Research involves electromechanical property (Polarization-Electric field, Stress-Polarization, Strain-Polarization) characterization of composition-driven ferroelectric ceramics designed for sensor applications. Development of piezo-ceramics with low-hysteresis and improved strain-electric field response is carried out.
Strategic applications involve SONAR-based piezo-acoustic transducer development for marine transport applications.
FEA-based piezo-vibro-acoustic analysis and design optimization of Tonpilz transducer.
Electromechanical characterization of synthesized piezo-ceramics with low-hysteresis and high-strain response using the experimental facility at the SMC Lab, IIT Madras. [5]
Modelling and Nonlinear Dynamical Response Characterization
in Multi-physical Systems
Characterization of Multiple Solutions and Attractor Basins of Initial Conditions
In this research, dynamical systems with multiphysical coupling in two or more physical domains (mechanical, flow, electric, magnetic, etc.) are modelled using energy-based approach. The resulting nonlinear system exhibits vivid dynamical response spectrum that includes multiple solutions of different periodic and chaotic nature.
Semi-analytical and computational methods are developed for unique and autonomous identification of period-n and chaotic responses of the system. Using methods and tools of nonlinear dynamics (purturbation, HBM, bifurcations, maps, Lypunov exponents, stability theory, etc.), responses are characterized and validated with developed experiments.
(a) Attractor basins of coexisting period-1 (intra-well (light blue) and cross-well (orange)) and chaotic (green) solutions of a bi-stable electromechanically coupled piezoelectric harvester. (b) Attractor basins of coexisitng multiple chaotic (green) and period-n (except green, all other colors) solutions. [3]
Characterization of Multiple Solutions using Semi-Analytical and Computational Methods
Electromechanical characterization of synthesized piezo-ceramics with low-hysteresis and high-strain response using the experimental facility at the SMC Lab, IIT Madras.
Frequncy-response of a bi-stable piezoelctric harvester system exhibiting multiple period-n solution branches. Time-histories and phase-portraits of the few solutions from these branches are shown with the red-colored stroboscopic and Poincaré points. [4]
Time and frequency domain sweep responses (at the top) capturing multiple periodic (harmonic and subharmonic) and chaotic solution regions are shown. Subharmonic responses (a to c) obtained using modified HBM are verified by computationally obtained responses with specific initial conditions. [4]
Modelling Flow-Structure-Electrical Multiphysical Interaction
In this work, models and experiments are developed to capture the fluid-structure-electrical interaction happening during the transduction of flow energy into mechanical and electrical energies. Prediction of specific experimentally recorded interactions (e.g. vortex-induced oscillations) are modeled using phenomenological models and CFD approach.
Wind-tunnel studies to evaluate the influence of bluff-body shape on vortex lock-in region.
