Our Research

Our work encompasses experimental studies as well as numerical modeling efforts. The main goal of our research is to apply fundamental engineering concepts to design and develop technologies. As a result our research process goes through a cycle of design, modeling, fabrication, testing and characterization, analysis, optimization, and prototyping. Our research is funded through few agencies including The National Aeronautics and Space Administration (NASA), Louisiana Board of Regents (La BoR), the Louisiana Space Consortium (LaSPACE), and the NASA Experimental Program to Stimulate Competitive Research program (EPSCORE). We also partner with NASA Stennis Space Center and Radiance Technologies. Current Research themes and projects include:

  • Nonlinear dynamic vibration systems in micro and macro environments.
  • Design, modeling, and characterization of vibration energy harvesting.
  • Design, modeling, and characterization of Vibration isolation systems.
  • Exploring vibration systems subject to combined stiffness and damping nonlinearities.

Design and Analysis of a Magnetically Levitated Energy Harvester Utilizing Oblique Mechanical Springs

Since most vibrational energy sources' frequency-response spectrum are broadband, the presented energy harvester is designed to generate electrical power across a wider frequency range. This nonlinear energy harvester consists of a magnetic mass in-between two stationary magnets. However, instead of using a guiding structure or tight-fit container, oblique mechanical springs are used to align the moving magnet and eliminate Coulomb dry friction. The hardening effect of the magnetic springs increases the resonant frequency of the system and the negative stiffness behavior of the mechanical springs improves the harvester's response towards the lower frequency spectrum. A nonlinear dynamic model of the device was developed using conservation laws and a proof-of-concept prototype was fabricated. Simulations and experiments showed good agreement and exhibited broad frequency spectra. For a base excitation of 0.75g, the proposed prototype generated a peak voltage and normalized power density of approximately 2.95V and 0.136mw/cm3g2, respectively. Although the normalized power density was not optimized, the prototype performed well with respect to other state-of-the-art electromagnetic energy harvester designs. Optimization of the proposed hand-held energy harvester prototype allows for the replacement of chemical batteries used in wireless sensor networks and mobile applications.

Design Enhancement and Non-Dimensional Analysis of Magnetically-Levitated Nonlinear Vibration Energy Harvesters

Over the past decade, there has been special interest in developing nonlinear energy harvesters capable of operating over a wideband frequency spectrum. Chief among the nonlinear energy harvesting techniques is magnetic levitation-based energy harvesting. Nonetheless, current nonlinear magnetic levitation-based energy harvesting approaches encapsulate design challenges. This work investigates some of the design issues and limitations faced by traditional magnetic levitation-based energy harvesters such as damping regimes and stiffness nonlinearities. Both experiment and model are used to quantify and evaluate damping regimes and stiffness nonlinearities present in magnetic levitation-based energy harvesters. Results show that dry friction, mostly ignored in magnetic levitation-based energy harvesting literature, contributes to the overall energy dissipation. Measured and modeled magnetic forces-displacement curves suggest that stiffness nonlinearities are weak over moderate displacements. To overcome some of these limitations, an enhanced design utilizing a combination of mechanical and magnetic springs is introduced. A non-dimensional model of the proposed design is developed and used to investigate the enhanced design. The unique potential energy profile suggests that the proposed nonlinear energy harvester outperforms the linear version by steepening the displacement response and shifting the resonance frequency, resulting in a larger bandwidth for which power can be harvested.

Fabrication and Characterization of a Non-Resonant Magneto-Mechanical Low-Frequency Vibration Energy Harvester

When externally excited, the energy harvester converts vibrations into electric charge using a guided levitated magnet oscillating inside a multi-turn coil that is fixed around the exterior of the energy harvester. The levitated magnet is guided using four oblique mechanical springs. A prototype of the energy harvester is fabricated using additive manufacturing. Both experiment and model are used to characterize the static and dynamic behavior of the energy harvester. Measured restoring forces show that the fabricated energy harvester retains a mono-stable potential energy well with desired stiffness nonlinearities. Results show that magnetic spring results in hardening effect which increases the resonant frequency of the energy harvester. Additionally, oblique mechanical springs introduce geometric, negative, nonlinear stiffness which improves the harvester's response towards lower frequency spectrum. The unique design can produce a tunable energy harvester with multi-well potential energy characteristics. A finite element model is developed to estimate the average radial flux density experienced by the multi-turn coil. Also, a lumped parameter model of the energy harvester is developed and validated against measured data. Both upward and downward frequency sweeps are performed to determine the frequency response of the harvester. Results show that at higher excitation levels hardening effects become more apparent, and the system dynamic response turns into non-resonant. Frequency response curves exhibit frequency jump phenomena as a result of coexistence of multiple energy states at the frequency branch. The fabricated energy harvester is hand-held and measures approximately 100.5 [cm3] total volume. For a base excitation of 1.0g [m/s2], the prototype generates a peak voltage and normalized power density of approximately 3.5 [V] and 0.133 [mW/cm3g2], respectively, at 15.5 [Hz].

Design and Analysis of a Duffing-Type Vibration Isolation System Employing Nonlinear-Damping and Nonlinear-Stiffness Elements

Undesired oscillations commonly encountered in engineering practice can be harmful to structures and machinery. Vibration isolation systems are used to attenuate undesired oscillations. Recently, there has been growing interest in nonlinear approaches towards vibration isolation systems design. This is because a linear vibration isolation system is most effective over narrow frequency bandwidth and when the excitation frequency is well above its natural frequency. This work is focused on investigating the effect of nonlinear cubic viscous damping in vibration isolation system consisting of a magnetic spring with a positive nonlinear stiffness, and a mechanical oblique spring with geometric nonlinear negative stiffness. Dynamic model of the vibration isolation system is obtained and Harmonic Balance Method (HBM) is used to solve the governing dynamic equation. Additionally, forth order Runge-Kutta numerical simulation is used to obtain displacement transmissibility of the system under investigation. Results obtained from numerical simulation are in good agreement with those obtained using HBM. Results show that introducing nonlinear damping improves the performance of the vibration isolation system. Nonlinear damping purposefully introduced into the described vibration isolation system appears to eliminate undesired frequency jump phenomena traditionally encountered in Quasi-zero-stiffness vibration isolation systems. Compared to its rival linear vibration isolation system, the described nonlinear system transmits less vibrations around resonant peak. At lower frequencies, both nonlinear and linear isolation systems show comparable transmissibility characteristics.

Theoretical and Experimental Investigation of an Elastic-Magnetic Vibration Isolation System

The isolation system features a combination of elastic and magnetic springs as well as viscous and magnetic damping components to facilitate its functionality. A mechanical spiral spring houses a solid permanent magnet that is levitated between two, top and bottom, stationary ring magnets. In this work, a prototype of the device is manufactured using rapid manufacturing. Dynamic and static characterization tests are performed and a nonlinear dynamic model is derived and solved using harmonic balance method. Additionally, finite element models are developed for the mechanical and magnetic springs. Results from models and experiment are in close agreement. Measured data and model simulation show that the three magnet arrangement results in a nonlinear magnetic spring with negative linear stiffness coefficient. The mechanical spiral spring exhibits linear behavior with a positive stiffness coefficient. Results from dynamic measurements and model simulation confirm the ability of the device to attenuate vibrations higher than 12.5 [Hz].

Hamzeh Bardaweel Ph.D.

Assistant Professor of Mechanical Engineering & Nanosystem Engineering.
Institute for Micromanufacturing
Room 212
911 Hergot Avenue
Ruston, LA 71272, U.S.A.
Phone: 318-257-5134
Email: hamzehb@latech.edu

Also check: Dr. Bardaweel's Google site, Google Scholar, and LinkedIn

News and Announcements

Congratulations to Hieu on his new 2019 journal publication ( Mono-stable and bi-stable magnetic spring based vibration energy harvesting systems subject to harmonic excitation: Dynamic modeling and experimental verification). Accepted for publication in Mechanical Systems and Signal Processing Journal (September 09 2019).
Mehdi successfully defended his PhD dissertation on August 5th 2019. Congratulations Mehdi!
Congratulations to Ghufran and Hieu on their new publication (High power density spring-guided nonlinear vibration energy harvester. Accepted for publication in Applied Energy on July 15th 2019)
Congratulations to Mehdi on his new publication ( Analysis and Optimal Design of a Vibration Isolation System Combined with Electromagnetic Energy Harvester. Journal of Intelligent Material Systems and Structures. 2019. DOI: 10.1177/1045389X19862377. PP. 1-14 )
Congratulations Ghufran Aldawood for successfully defending her Master degree thesis (Electrical Engineering Concentration) on June 11th 2019.
Congratulations Hieu Nguyen for successfully defending his Master degree thesis (Mechanical Engineering Concentration) on June 11th 2019.
Congrats to Stephen and Logan who are graduating this May!
Winner Anigbogu is joining our lab starting Spring 2019! Welcome aboard.
Congrats to Mehdi Mofidian for his new publication "Theoretical Study and Experimental Identification of Elastic-Magnetic Vibration Isolation System" published in Journal of Intelligent Material Systems and Structures. Will appear online later this year!
Congrats to Johnny and Logan! "Fabrication and characterization of non-resonant magneto-mechanical low-frequency vibration energy harvester" published in Mechanical Systems and Signal Processing Journal. Will appear on line later this year...
Congrats to Mehdi Mofidian on his new publication: Displacement Transmissibility Evaluation of Vibration Isolation System Employing Nonlinear-Damping and Nonlinear-Stiffness Elements has been accepted for publication in Journal of Vibration and Control ( accepted on July 3rd 2017).
Austin Smith awarded LaSPACE Graduate Student Research Award (GSRA). PI: Dr. Hamzeh Bardaweel Title: Geometric fidelity and dimensional characteristics of microfluidic networks fabricated using additive manufacturing. $8,000. September 1 2017- August 31 2018.
Stephen Bierschenk awarded LaSPACE Undergraduate Research Assistantship (LURA). PI: Dr. Hamzeh Bardaweel Title: Managing satellite micro-jitters using energy harvester dynamic vibration isolation platform $6,000. September 1 2017- August 31 2018.
Dr. Bardaweel has received the NASA LASPACE RESEARCH ENHANCEMENT AWARD grant. Title: Design, characterization and hydrodynamic optimization of 3D printed embedded micro-channels networks. PI, $34,974 July 1, 2017 through June 30, 2018.
Dr. Bardaweel has received the LOUISIANA BOARD OF REGENTS-BOARD OF REGENTS SUPPORT FUND grant. Title: Regenerative Hybrid Hydraulic- Electromagnetic Shock-Absorber. PI, $39,974, June 1, 2017 May 31, 2018. Dr. Bardaweel's proposal ranked number one among all proposals submitted in State of Louisiana!
Congrats to Abullah on his new publication: Nammari, A. and H. Bardaweel, Design enhancement and non-dimensional analysis of magnetically-levitated nonlinear vibration energy harvesters. Journal of Intelligent Material Systems and Structures.March 27, 2017
Congratulations to Logan, Stephen, and Johnny on their acceptance to the CIMM REU program for Summer 2017. February 20, 2017
Abdullah Nammari's second manuscript "Design and analysis of a small-scale magnetically levitated energy harvester utilizing oblique mechanical springs" submitted to Journal of Microsystem Technologies has been accepted for publication. February 9, 2017
Abdullah Nammari's manuscript "Design and Analysis of Magnetically-levitated Nonlinear Vibration Energy Harvesters" accepted for publication by the Journal of Intelligent Material Systems and Structures . February 7, 2017
Dr. Bardaweel received NSF(2017)-CIMM grant. Project Title: 3D Printable Structures for Multi-functional Vibration Energy Scavenger. $10,000 January 1, 2017 through December 31, 2017.
Dr. Bardaweel received NASA EPSCoR RAP grant. Title: Multi-functional non-resonant magnetically-levitated energy scavenger for NASA Stennis Space Center (SSC) $39,889 January 15, 2017 through January 14, 2018.
Dr. Bardaweel received NASA LASPACE REA grant. Title: Broadband Nonlinear Vibration Energy Harvesting for Aerospace Applications $34,875 September 1, 2016 through August 31, 2017.
Dr. Bardaweel received Louisiana Tech Technology Fee Grant. Title: DESKTOP COMPUTERS FOR MICRO/NANOSYSTEMS MODELING AND SIMULATION LABORATORY $38,325 December 1, 2016 through November 31, 2017.
Abdullah Nammari awarded LaSPACE Graduate Student Research Award (GSRA). PI: Dr. Hamzeh Bardaweel. Title: Fabrication and Characterization of Broadband Nonlinear Electrogagnetic Energy Harvester. $8,000. August 15 2016- August 14 2017.
Logan Caskey awarded LaSPACE Undergraduate Research Assistant (LURA). PI: Dr. Hamzeh Bardaweel Title: Dynamic Analysis and Design Optimization of a Regenerative Shock Absorber. $6,000. September 1 2016- August 31 2017.
Johnny Negrete awarded LA EPSCoR Supervised Undergraduate Research Experiences (SURE). PI: Dr. Hamzeh Bardaweel Title: Developing 3D-printable structures for microvibration isolation system.. $5,000. January 1, 2017 through December 31, 2017.