Expert Details

Expert in Compliant Mechanisms, Flexure/Torsion Hinges, MEMS, Microsystems, and Finite Element Analysis

Expert ID: 722746 Romania

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Expert notes that both of Castigliano's theorems are excellent tools in quantifying deformations and loads (external or reaction) of elastic bodies under small- or large-deformation modeling assumptions. He has extensively applied these theorems in finding closed-form solutions for compliances or stiffnesses of flexible connectors, such as the flexure/torsion hinges, as well of various flexible (compliant) suspensions in micro/nano electromechanical systems (MEMS/NEMS).

Expert notes that compliant mechanisms use elastic deformation (either small or large) of their flexible members in order to transform an input energy into an output energy form (generally mechanical). He has extensively worked on modeling, analyzing, optimizing, and designing compliant mechanisms that are based on monolithic hinges (they deform either in bending or torsion) and that have macro- and micro-scale engineering applications such as precision positioning devices, microcantilevers, microbridges, displacement-amplification devices, microactuators, or microsensors. He is author of a 2002 book that thoroughly covers this class of mechanisms, by studying various monolithic hinge configurations (single-axis, two-axes and multiple-axes; circular, corner-filleted, elliptic, parabolic, and hyperbolic), and the static as well as the dynamic response of hinge-based compliant mechanisms. He utilizes both analytic and finite element modeling to characterize the monolithic hinges and the hinge-based compliant mechanisms.

Expert has directly worked on designing various mechanical devices, such as precision positioning stages, piezoelectrically-driven mechanisms, amplification/de-amplification devices, and microelectromechanical devices. He uses the model-based design as a primary concept in producing first-iteration designs, followed by the finite element design method as a refinement stage.

Expert notes that mechanical engineering analysis is the necessary phase following mechanical engineering modeling. By using analytical or numerical models, he has performed numerous simulations aimed at producing optimized component/system mechanical designs in either the macro or micro (MEMS) domains.

Expert has been working lately in this domain by attempting to gain insight from a mechanical engineer's viewpoint and by studying models in the static and dynamic domains of various microelectromechanical (MEM) devices. Transduction methods and implementations that serve either actuation or sensing purposes (or both, as the case is with sensory-actuation) at the micro/nano scale have also been addressed in his work. He is co-author of a 2004 text that contains a thorough treatment and numerous solved and proposed examples where concepts such as microhinges, microcantilevers, microbridges, microsuspensions, microtransduction, microfabrication, materials, scaling laws, and microsystem design in the static domain are detailed.

Expert notes that micromechanical systems are at the core of microsystems; he has dedicated a great deal of attention to these systems, especially to compliant micromechanical devices, which are predominantly utilized at a small scale as feasible solutions for realization of mobility/motion transmission. He has focused on the modeling of compliant (flexible) micromechanical members, such as flexure/torsion hinges, microsprings (microsuspensions), microcantilevers, and microbridges, as well as on their integration into the microsystem. He has studied both the static (quasi-static) and resonant (dynamic) response of mechanical microsystems. He is author of a 2005 book that addresses the modeling and design of mechanical microresonators, such as microcantilevers, microbridges, microgyros, and other oscillators.

Expert has worked on model-based design of precision devices/mechanisms such as stages, alignment devices, and micromechanisms, particularly on compliant ones. He has analyzed the precision of utilizing various levels of modeling in hinge-based compliant mechanisms and flexible microelectromechanical systems (MEMS). He has worked extensively on modeling the precision of hinges and compliant mechanisms and on quantifying the errors that are set by various modeling assumptions as a function of small/large deformations (linear/nonlinear models) or long/short members (Euler-Bernoulli/Timoshenko models).

Expert constantly relies on methods from mechanics of materials, statics, dynamics, and vibrations (which are all branches of mechanics) in order to evaluate the behavior of various mechanical systems. Classical or Newtonian mechanics remains a domain that offers valuable solutions to everyday mechanical engineering problems, and he is largely considering this area as a primary design tool. He has extensive expertise in applying static and kineto-static methods to various mechanical engineering problems as a first-stage design tool. Compliances and stiffnesses, as well as amplification ratios and bloc load levels, have been topics of interest in both macro- and micro-scale applications that he has solved. Expert has worked extensively with dynamic modeling, analyzing and designing of mechanical systems by employing both analytical and numerical (finite element) tools. Focus has been directed to rotordynamics, elastodynamic locomotion, resonant motion, harmonic analysis, and frequency-domain and time-domain responses. Expert has studied mechanical vibration problems addressing rotordynamics, modal analysis, harmonic analysis, and damping by using analytical and finite element modeling/analysis. Resonant behavior, especially in the cases of elastodynamic locomotion and mechanical microresonators, has been a topic of particular interest of his research.


Year Degree Subject Institution
Year: 1996 Degree: Ph.D. Subject: Mechanical Engineering Institution: Technical University of Cluj-Napoca, Romania
Year: 1985 Degree: B.Sc. Subject: Mechanical Engineering Institution: Technical University of Cluj-Napoca, Romania

Work History

Years Employer Title Department Responsibilities
Years: 2004 to Present Employer: Undisclosed Title: Professor Department: Responsibilities:
Years: 2002 to 2004 Employer: Cornell University Title: Research Associate Department: Sibley School of Mechanical and Aerospace Engineering Responsibilities: Expert performed research on microelectromechanical systems (MEMS), compliant mechanisms, walking robots, and morphing aero-structures. He also taught System Dynamics for two semesters (2003 and 2004).
Years: 1999 to 2002 Employer: Dynamic Structures and Materials, Franklin, TN Title: Research Engineer Department: Responsibilities: He performed research on compliant mechanisms, flexure hinges, piezoelectric actuators, solid-state amplification mechanisms, shape memory alloys, composite structures, special textile fabrics, exoskeleton protective gloves, health monitoring, and thermo-electric power generation.
Years: 1997 to 1999 Employer: Vanderbilt University Title: Research Associate Department: Department of Mechanical Engineering Responsibilities: Expert performed research on mesoscale robotic insects for elastodynamic locomotion and piezoelectric actuation. He also taught Dynamics for two semesters (1998 and 1999).
Years: 1990 to 1997 Employer: Technical University of Cluj-Napoca, Romania Title: Associate Professor Department: Strength of Materials Responsibilities: He did teaching and research in mechanics of solids, structures, vibrations, rotordynamics, finite and boundary element methods, and optimization.
Years: 1987 to 1990 Employer: Center for Laboratory Equipment Research and Development, Cluj-Napoca, Romania Title: Engineer Department: Responsibilities: Expert performed research and design of laboratory equipment: robotic manipulators for physical/chemical analysis.
Years: 1985 to 1987 Employer: Center for Research and Engineering Technology, Cluj-Napoca, Romania Title: Engineer Department: Responsibilities: He performed research and design of packaging and textile machinery.

Career Accomplishments

Associations / Societies
Expert is a member of ASME (American Society of Mechanical Engineers) and
AGIR (Romanian Society of Engineers).
Publications and Patents Summary
He has 20 journal papers and over 50 conference/congress presentations, mainly on flexure hinges, compliant mechanisms, and MEMS. He has published three books in the last 15 years.

Language Skills

Language Proficiency
Romanian Romanian is Expert's mother tongue.
French He does well in speaking, reading, and writing French.

Fields of Expertise

Castigliano's theorem, compliant mechanism, mechanical device design, mechanical engineering analysis, micro electrical-mechanical system, micromechanical system, precision machine design, mechanics, vibration, dynamics, statics, nanomaterial, load combination, microrobotics, dynamic load (structural system), load (force), flight dynamics, cam design, fluid system dynamics, nanostructure, nanowire, applied mechanics, biodynamics, machine installation, airframe stress analysis, Lithographie Galvanoformung Abformung, absolute temperature scale, rotor dynamics, microaccelerometer, virtual work, shear strength, final drive, metal mechanics, mechanical joining, mechanical reliability, Newtonian mechanics, force ratio, degree of freedom, bearing design, nonlinear mechanics, thermal stress, mechanical system dynamic response simulation, dynamic force analysis, industrial machine design, stress concentration, strain analysis, couple balance, continuum mechanics, machine design review, nanotechnology, advanced material, special machine design, assembly machine design, structural dynamics, machine safety, dynamic balance, mechanical power transmission, machine design, conveyor design, automated machine design, micromechanics, microelectromechanics, vehicle dynamics, composite material micromechanics, rigid-body dynamics, nano-stepper motor, scalar quantity, vector quantity, linear momentum, framework, mechanical system, thermal converter, machine, force, power shaft, truss, thermodynamics, structural optimization, structural mechanics, statistical mechanics, static fatigue, spring, microfabrication, microactuator, mechanical engineering, linkage, kinetics, kinematics, hydrostatics, harmonic motion, gear, fracture mechanics, fluid mechanics, fluid dynamics, fluid drive, flight mechanics, clutch, classical dynamics, cam (device), pulley, ballistics, angular momentum, aerospace engineering

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