Research Tasks

Rotorcraft aeromechanics, smart structures and micro air vehicles research programs at the Alfred Gessow Rotorcraft Center.

Worked on various fundamental multidisciplinary/interdisciplinary research problems of helicopters including

  • aeromechanical stability
  • aeromechanics analysis and testing of Mach-scale coaxial rotos
  • aeromechanics analysis and testing of Mach-scale rotos at high advance ratios
  • rotor-body-engine coupled aerolastic analysis
  • prediction of vibration and loads
  • CFD coupling with comprehensive analysis to predict loads and performance
  • development of swashplateless rotor systems
  • Aeromechanics and mast bumping of teetering rotors
  • Preliminary design using comprehensive analysis
  • active vibration control
  • modeling of composite coupled rotors
  • rotor head health monitoring
  • aeroelastic optimization
  • damping identification
  • adaptive control strategies
  • wire strike studies
  • wing vortex upsets and gust response studies
  • innovative rotor designs including swashplateless rotor systems
  • modeling and applications of smart structures
  • micro air vehicles: aeromechanics, autopilots, navigational strategies, wind tunnel and flight testing
  • micro air vehicles: single main rotors, quad-rotors, shrouded-rotors, cyclocopters, quad-biplane, flapping wings
  • comprehensive aeromechanics analyses of bearingless, tilt-rotor, teetering, coaxial, compound, servo-flap, and circulation control rotors

Research is balanced between analysis and experimental testing under controlled environment.

Most Notable Research Contributions

Dr. Chopra’s Research is characterized by:

Dr. Chopra’s research is characterized by: i) balance between theoretical analysis and experimental testing with the belief that both are essential to technology advancement, ii) multidisciplinary fundamental research covering dynamics, aerodynamics, composite structures, actuators and sensors, and controls, iii) emphasis on creativity, and vi) willingness to take on a number of new and challenging areas and make significant contributions before most other researchers. Pioneering research contributions were made towards the aeromechanics of composite-coupled, bearingless, servo-flap and circulation-controlled rotors, structural health monitoring, CFD prediction of loads. Smart structures and micro air vehicles. Overall, the research contributions of his group show creativity, relevance and diversity. For research contributions, see state-of-art reviews on rotorcraft aeromechanics as well as smart structures (Friedmann [97], Johnson [86, 2015], Ormiston [96,99] and Loewy [97], Chopra [00, 02, 08]).

  1. Developed the very first finite element analysis of bearingless rotor blades involving redundant-load-paths. Today it is an accepted standard in the rotary-wing field.
  2. Pioneered the dynamic analysis of composite rotors and showed the importance of structural couplings on aeromechanical stability and vibratory loads. Following this work, numerous researchers and industry have carried out in-depth studies on this topic.
  3. Pioneered the development of aeroelastic analysis of circulation control rotors and wings. It was closely tied to the development of a revolutionary aircraft, called the X-Wing that was funded by NASA and DARPA.
  4. Developed comprehensive aeroelastic analyses for advanced rotor systems in forward flight. Other researchers and industry vigorously followed these developments to upgrade their analyses/codes. Synthesized numerous of his students’ Ph. D. dissertations into a comprehensive code UMARC (University of Maryland Advanced Rotorcraft Code) that has been used by industry, academia and government laboratories (Boeing, Sikorsky, Bell, NASA Ames, NASA Langley, U.S. Navy, ATI, Army-Aberdeen, Army-Fort Eustis, Army-Huntsville, Praxis Technology, Navy David Taylor R&D Center, Wagner Aeronautical, McIntosh SDI, Penn State, Arizona State University, Stanford University, University of Tennessee, UT-Austin, University of Wyoming).
  5. Formulated a practical and efficient multidisciplinary aeroelastic optimization procedure for helicopter rotors to minimize vibration and improve aeromechanical stability. This holds enormous potential for the development of future rotors.
  6. Developed a comprehensive analysis for vibration control of helicopters to cover severe flight conditions, including maneuvering flights. It was the very first analysis that showed the importance of dynamic stall on the performance of higher harmonic vibration control and actuation power. In fact, this side effect is one of the major barriers to this vibration suppression technique.
  7. Developed a new identification technique called Sparse Time Domain to identify modal parameters from rotor stability test data. It was used successfully in the stability test of an advanced bearingless rotor in the Glenn L. Martin wind tunnel.
  8. Pioneered the development of an intelligent rotor system using smart structures technology to minimize vibration and improve performance with embedded as well as surface-mounted actuators. Numerous researchers from industry, academia and research laboratories in the US and abroad are now working on these concepts. Through collaborations with rotorcraft industry (Boeing and Sikorsky), full-scale smart rotors were developed.
  9. Formulated analyses for open-section and closed-section thin-walled coupled composite beams, and validated these by building and testing numerous composite beams under static and dynamic loading (including tests in vacuum spin chamber). Many researchers now use these predictions and data as reference for validation of their analyses.
  10. Formulated the very first simple but precise model of an elastomeric damper. This model is now widely adopted by industry and research community.
  11. Developed a comprehensive aeroelastic analysis of tiltrotor aircraft including advanced rotor and wing configurations.
  12. Developed the basic guidelines for rotor system fault detection. Navy adopted this methodology for a major DoD national initiative on rotorcraft health monitoring system called JAHUM.
  13. Pioneered modeling and testing of smart actuators and sensors that involve piezoelectric, magnetostrictive and shape memory alloy materials. Many of these tools are now widely used by other researchers.
  14. Developed design studies for a swashplateless rotor with active trailing-edge flaps for primary and vibration controls. Collaborated with NASA and industry for the development of full-scale rotor systems.
  15. Developed consistent couplings of CFD with comprehensive analysis and solved the long-standing problem of vibratory loads prediction in a high-speed flight. It was a part of academia/government/industry loads prediction workshop.
  16. Pioneered the development of Micro Hovering Air Vehicles. Several different types of MAV configurations have been developed, which included: single main rotor, shrouded-rotor, quad-rotor, quad-biplane, cyclocopter, and flapping-wings. Not only developed the aeromechanics tools, but also developed micro-autopilots and navigational tools.
  17. Pioneered the testing of Mach-scale rotors in very high advance ratios (up to 1.5 ). These data are vital for the development of next generation high-speed compound rotorcraft.
  18. Developed comprehensive aeromechanics analysis and test data for a Mach-scale coaxial rotor.
  19. Developed comprehensive coupled analysis of rotor-body-engine (collaboration with GE and Sikorsky)
  20. Developed preliminary design code using comprehensive rotorcraft analysis.

Other Notable Contributions

He played a key role in the hiring and mentoring of outstanding faculty members at the Rotorcraft Center, and more importantly in the Department of Aerospace Engineering as well as in the Department of Mechanical Engineering. He has been instrumental to put together a comprehensive and vibrant graduate education program in rotorcraft engineering at the University of Maryland, which had always been envisaged as a vital part of ongoing graduate research. New courses were added through timely hiring of new faculty members in specialized areas. Not only that he has been successful in developing a model education program in rotorcraft engineering, but also, he has successfully passed on his insights and experiences to several other research groups in the Department of Aerospace Engineering as well as in other Departments in the A. J. Clark School of Engineering to achieve excellence in both education and research.

Most Notable Experimental Facilities

Since the inception of the Rotorcraft Center at the University of Maryland in 1982, many unique rotorcraft-related experimental facilities have been developed. Many of these facilities are unparallel at any other educational institution in this country or abroad and are now fully functional and routinely used by graduate and undergraduate students and industry.

  1. Built two special “model rotorcraft rigs” respectfully for Mach-scale and Froude-scale testing. This facility is used to test scaled helicopter models in the Glenn L. Martin wind tunnel as well as on our hover stand for evaluation of aerodynamic and dynamics characteristics. In conjunction with this facility, we have acquired sophisticated data acquisition system and other instrumentation. Because of this model rig, many collaborative research tasks with industry, Army and NASA were undertaken. There are one of a kind facilities at any university.
  2. Built a unique “10-ft. Diameter Vacuum Chamber”. It is a one-of-its-kind facilities in the country to test rotor models in a rotating environment (up to 2000 RPM) and in total vacuum (i.e., in the absence of aerodynamic forces). Today, it is one of the busiest facilities, used by graduate students, faculty and industry to test their rotor models in vacuum.
  3. With the support of the Engineering Research Center, initiated the setting-up of Composite Research Laboratory in the Department of Aerospace Engineering in the 1980’s. Later on, other faculty members contributed in further enhancement of this Laboratory into one of the most modern composite laboratories at a university. It is now widely used by undergraduate and graduate students and faculty from several departments as well as by industry.
  4. Developed a fabrication facility to build scaled-rotor models at the Rotorcraft Center. This saved enormous fabrication cost and time to build rotor models as well as helped us to pursue innovative design concepts.
  5. In collaboration with Mechanical Engineering, Materials Engineering, and Institute for Systems Research, Dr. Chopra initiated the setting-up of modern smart structure facilities on this campus. Because of timely development of these facilities, the campus won several major national programs (4 MURIs, 6 DARPAs) and many other major research grants.
  6. Through a collaboration with Mechanical Engineering and Electrical and Computer Engineering, initiated the setting-up of fabrication, testing, imagery and navigational technology for micro air vehicles at the University of Maryland (MURI).

Most Notable Interdisciplinary Research Programs/Centers

  1. Alfred Gessow Rotorcraft Center: Since its inception in 1982, the Rotorcraft Center at the University of Maryland has been one of the three Rotorcraft Centers of Excellence, supported by federal funds for most of the years, initially by the Army Research Office (1982-95) and then through the Army/Navy/NASA National Rotorcraft Technology Center (1996-2006, 2011-16). The Center carries out multidisciplinary/interdisciplinary research in various aeromechanics disciplines of rotorcraft systems. The core rotorcraft program involves aerodynamics, dynamics, flight mechanics, computational fluid dynamics, acoustics, composite structures, transmission and power trains, smart structures, micro air vehicles and advanced designs. In addition to the core rotorcraft program, four major Army-sponsored national research programs and five major DARPA sponsored research programs were won by the Center competitively. Two of the Army-sponsored programs were focused on smart structures (a URI and a MURI) and other two were focused on micro air vehicles (a MURI and a CTA-MAST). Among DARPA-sponsored programs, two were focused on application of smart structures technology to rotorcraft systems, two were focused on development of new smart actuators, and fifth was focused on rotorcraft acoustics prediction. The success of the Center is attributed to the timely addition of outstanding faculty, opportunity driven research programs, high level of productivity, comprehensive experimental facilities, demonstrated technology transfer to industry and outstanding graduate students. The Rotorcraft Center at the University of Maryland is one of two continuously funded centers for over three decades in the country. The Center has a very high level of sustaining research productivity. For example, during the past one decade, the UM Rotorcraft Center has published more rotorcraft-related archival papers than any other institution in this country or abroad. Another example, during the past decade, the Center has presented the largest number of papers than any institution (over 20 papers per year) at the Annual Forum of the American Helicopter Society (a premium conference in rotorcraft). During the past 20 years, our smart structures group has dominated the SPIE Smart Structures and Materials Symposium (a premium smart structure conference) in terms of paper presentations. Over the years, we have successfully attracted many talented graduate students to our Center. For example, the American Helicopter Society awards every year competitively 10 to 15 Vertical Flight Foundation Scholarships and our students have won about 25% of total scholarships during the past fifteen years. The Center has graduated many outstanding students who have now developed into leaders in industry, government laboratories and academia, in abroad and US. Most of our graduates are extremely productive in their respective endeavors. Every year, the American Helicopter Society recognizes one outstanding young contributor to the vertical flight technology with the Francois Xavier Bagnoud Vertical Flight Award. Since the inception of this award in 1993, our graduates have won this award overwhelmingly. Also, the director and founder of another rotorcraft center of excellence (i.e., Penn State) graduated from our Center.
  2. Smart Structures URI: Instrumental in initiating interdisciplinary basic research activities in smart structures in the A. J. Clark School of Engineering. In 1992, he put together a team of faculty comprising from Aerospace Engineering, Mechanical Engineering, Materials Engineering, Institute for Systems Research mostly Electrical Engineering and UMBC and won a five-year University Research Initiative (URI) entitled “Innovations and Applications of Smart Structures Technology to Rotorcraft Systems” (1992-97) from the Army Research Office. As part of the URI, the basic elements of smart structures pertaining to rotorcraft were developed. Much of the research was directed towards development and refinements of: hybrid material actuators, magnetostrictive particle actuators, electrostrictive actuators and shape memory alloys actuators; sensors such as fiber optics; smart dampers such as electro-rheological and magneto-rheological fluid dampers; distributed control strategies such as wavelet theories; and analytical modeling of smart structures. Another key component of this research was focused on the development of Froude-scaled smart rotor models: controllable twist models incorporating embedded piezoceramic elements, and trailing-edge flap models actuated with smart actuators, to minimize vibration. Because of this program, there has been phenomenal growth of research activities in smart structures on this campus. Many new smart structures facilities that were partially supported by our program were built in different departments. This URI seeded smart structures activities at Maryland and helped won many major national programs that include:
    • Our own MURI in collaboration with Penn State and Cornell (1996-2001)
      MURI by ISR in collaboration with Harvard and Boston University “Center for Dynamics and Control of Smart Structures” (1997-2001)
    • SMSRC: Smart Materials and Structures Research Center (Mech. and Aero. Engineering)
    • DARPA: High Performance Actuators Research (UM-Materials in collaboration with MIT, Minnosota and Washington)
    • DARPA: Full-Scale Smart Rotor Development (1995-98), (Team members: McDonnell Douglas, Maryland, Xinetics and Memry).
    • JAHUM: Navy’s Rotor Head Structural Health Monitoring (1995-2000).
  3. Smart Structures MURI: Following the success of our smart structures URI, we won a Multidisciplinary University Research Initiative (MURI) entitled “Innovative Smart Technologies for an Actively Controlled Jet-Smooth Quiet Rotorcraft” (1996-2001). For this, we led a team of researchers from the University of Maryland (Aerospace and Mechanical Engineering), Penn State, Cornell, and University of District of Columbia. This MURI program further expanded the smart structures technology base by examining new innovative actuators, sensors and control strategies, and addressed high-payoff applications to rotorcraft to suppress external/internal/ transmission noise and vibration. Most importantly, this research program contained the next and vital step in the practical application of smart structures technology to suppress noise and vibration in full-scale systems by building Mach-scaled rotor models and testing them on our hover stand and in the Glenn L. Martin wind tunnel. Today, we have established a leadership in the smart structures discipline. For example, at an International Conference on Adaptive Structures and Technologies (ICAST) held at College Park, MD (October 2001), every other paper had its roots in the University of Maryland. During the past twenty years, Maryland has contributed more papers in smart structures discipline than any other institution in this country or abroad. As a result of this, the A. J. Clark School of Engineering has won many new initiatives and programs:
    • Small Smart Systems Center (Campus Initiative)
    • DARPA: Full-Scale Smart Rotor Demonstration Program (1998-02),
      (Team members: Boeing, Maryland, UCLA, MIT).
    • DARPA: Compact Hybrid Actuators Program (CHAP) (2000-03),
      (Team Members: CSI and Maryland)
    • MURI: Ferro-Magnetic Shape Memory Actuators (2001-06)
      (Team Members: Maryland, Minnesota and VPI)
  4. Micro Air Vehicle MURI: Following the success of our smart structures programs, we won a new MURI entitled “Micro Hovering Air Vehicles: Revolutionary Concepts and Navigational Advancements” (2004-2009). For this, we led a team of researchers from the University of Maryland (Aerospace, Mechanical and Electrical & Computer Engineering), Australian National University (ANU), and North Carolina A&T University (NCAT). The objective of this interdisciplinary/multidisciplinary research program was to rapidly accelerate the development of the next generation hovering micro air vehicles (MAVs) that are equipped with biologically inspired navigation, guidance and collision avoidance algorithms in support of a variety of DOD applications. Key scientific barriers towards building a highly maneuverable, long endurance and efficient hovering system were overcome by building on the expertise of UM in the design and development of efficient micro hovering air vehicles and image processing, of ANU in the use of revolutionary insect-based visual guidance techniques, and of NCAT in the manufacturing of multi-functional materials and composite structures technology.
  5. MAST-CTA: Center for Microsystem Mechanics: Following the success of our MAV-MURI, we won a multiyear CTA-MAST program entitled “Center for Microsystem Mechanics” (2008-18). For this, we led a team of researchers from the University of Maryland (Aerospace and Mechanical), Berkeley, Caltech, UT-Austin, Texas A&M, Harvard, Georgia Tech, North Carolina A&T, Polytechnic-Milano. The objective of this interdisciplinary Center has been to develop flying and ambulatory platforms that have the needed mobility for the ARL Microsystems vision goals. The goal has been to address integrated phenomena and develop fundamental mechanics tools for the next generation of highly maneuverable microsystems to successfully operate them in both confined environments (such as building interiors, caves, and tunnels) and unconfined environments (such as battle zone perimeter defense), encompassing rough terrain and gusty wind conditions. The research program has been comprised of four areas (aeromechanics, ambulation, hybrid aeromechanics/ambulation and multifunctional actuation) consisting of 19 subtasks, involving 18 faculty members in eight different institutions supporting over 30 graduate students.

External Research Support

  1. Establishment of Center for Rotorcraft Education and Research (U.S. Army Research Office), Task Leader for five tasks out of twelve total research tasks, (Principal Investigator: Prof. Alfred Gessow), Five years award (1982-87): (Total Award: $4.6M) Chopra’s Tasks: $1.8M.
  2. Gust Response of Articulated and Hingeless Rotors in Hover and Forward Flight, (NASA/Langley), 3 years (1983-86): $167K
  3. Study of Wake-Vortex Induced Upset of a Helicopter, (Department of Transportation, FAA), 2 years (1984-86): $75K
  4. Unsteady Interaction of a Jet and Boundary Layer, (Navy David Taylor Research Center), 1 year (1985-86): $35K
  5. Completion of Helicopter Model Test Rig, (DOD/Army Research Office), 1 year (1984-85): $250K
  6. Aeroelastic Stability of Bearingless Rotors in Forward Flight (NASA Ames Research Center), 8 years (1986-95): $413K
  7. Aeroelastic Optimization of a Helicopter Rotor, (NASA Langley Research Center), 6 years (1986-92): $283K
  8. Aeroelastic Stability Analysis of a Gimbaled Rotor, (NASA Langley Research Center), 2 years, (1988-90): $75K
  9. Instrumentation for Rotorcraft Model Testing, (DOD/Army Research Office), 1 year (1988-89): $130K
  10. A Comprehensive Rotorcraft Analysis Code, (NASA Ames Research Center), 1 year (1989-90): $44K.
  11. Center for Rotorcraft Education and Research, (Army Research Office), Task Leader for 3 out of 9 Research Tasks, Principal Investigator: Prof. Alfred Gessow for first 4 years and Chopra for last year, 5 years (1987-92): (Total $2.3M), Chopra’s Tasks: $1M
  12. Dynamic Analysis of an Advance Tiltrotor Airplane, (NASA Langley Research Center), 3 years (1991-94): $195K
  13. Fourth Workshop on Dynamics and Aeroelastic Stability Modeling of Rotorcraft Systems, (Army Research Office), 1 year (1991-92): $20K
  14. NASA Training Grant for a Graduate Student, (NASA), 2 years (1991-93): $44K
  15. University Research Initiative (URI): Smart-Structures Technology: Innovations and Applications to Rotorcraft Systems, (Army Research Office), (Team of 14 faculty members from Aerospace, Mechanical, Materials, ISR and UMBC, supported over 20 graduate students), 5 years (1992-97): $1.8M
  16. Center for Rotorcraft Education and Research, (Army Research Office & Rotorcraft Industry Consortium of Sikorsky, Bell, Boeing and McDonnell Douglas), (Other Team Members: Leishman, Celi, Lee and Vizzini, supported over 15 graduate students), 3 years, (1992-95): $1.75M
  17. International Travel to attend Symposium at I. I. Sc. Bangalore, India, (National Science Foundation), 6 Months (1992-93): $8.3K
  18. Instrumentation for Center for Rotorcraft Education and Research, (Army Research Office), (Co-PIs: Leishman and Vizzini), 1 years, (1993-94): Total Award: $446K, Chopra’s Share: $200K
  19. Augmentation Center for Rotorcraft Education and Research, (Army Research Office), (Other Team Members: Leishman, Celi, Lee, Vizzini, Baeder, Wereley, supported over 10 graduate students), 2 years (1994-96), $1.03M
  20. Evaluation of Methodology for Testing and Analysis of Advanced Rotors, (NASA Ames Research Center), 6 years (1993-99): $358K
  21. Helicopter Vibration Reduction with Dynamically Tuned Blade Pitch Links, (NASA Ames Research Center), 2 years (1994-96): $80K
  22. Health Monitoring of a Rotor Head System, (Navy David Taylor Research Center), 3 years (1994-97): $304K
  23. Smart Materials and Structures Development, (McDonnell Douglas Helicopter Co.), 2.5 years (1994-97): $170K
  24. Second Workshop on Smart Structures, (Army Research Office), 1 year (1995-96): $20K
  25. Development of High Force, High Displacement Actuators, (Army/Ames), 1 year (1995-96): $30K
  26. Center for Rotorcraft Education and Research, (National Rotorcraft Technology Center), (Other Team Members: Leishman, Celi, Vizzini, Baeder, Wereley, Pines, 15 supported graduate students), 5 years (1996-2001): $4.62M,
  27. NASA Graduate Student Fellowship for Jeanette Epps, (NASA), 3.5 years (1996-99), $74K
  28. DURIP: Instrumentation for Structural Integrity of Rotorcraft Systems, (Army Research Office), (Co-PI with Wereley, Pines and Sirkis), 1 year (1996-97): (Total Award $289K), Chopra’s Share: $96K
  29. Multidisciplinary University Research Initiative (MURI): Innovative Smart Technologies for an Actively Controlled Jet-Smooth Quiet Rotorcraft, (Army Research Office), (Team Members from UM, Penn State, Cornell and UDC, 18 faculty, 21 research tasks, 21 supported graduate students) 5 years (1996-2001): $5M
  30. Methodology Development for Helcopter Rotor System Health and Usage Monitoring, (Naval Surface Warfare System: Carderock Division), 5 year (1998-2003), $531K
  31. Smart Material and Structures Development, (Boeing Mesa), 3 years (1998-2001), $626K
  32. Mach Scaled Smart Rotor Model, (Boeing Mesa), 5 years (1996-2001), $300K
  33. Smart Rotor Development, (Sikorsky), 2 years (1996-98), $100K
  34. IPA for Dr. Roichenbach, (NASA Ames Research Center), 2 years, (1998-2001), $425K
  35. Evaluation of Methodology for Testing and Analysis of Advanced Rotor Systems, (NASA Ames Research Center), 6 years (1999-05), $1.218M
  36. Tailored Composite Couplings in Helicopter Blade, (Sikorsky), 5 years, (1999-2004), $320K
  37. IPA for George Price, (NASA Ames Research Center), 1 years, (2000-2), $290K
  38. Center for Rotorcraft Education and Research, (NRTC), (Other Team Members: Leishman, Celi, Schmitz, Baeder, Wereley, Pines, Etkins, Shapiro and Baz, 15 supported graduate students), 5 years (2001-2006): $4.64M.
  39. Research Augmentation for Center for Rotorcraft Education and Research (NRTC), 4 years (2002-2005), 400K
  40. Whirl Flutter of Two-Bladed Propellor/Pylon System: Evaluation of Methodology for Testing and Analysis of Advanced Rotor Systems, NASA Langley Research Center, one year, (2001-2), $40K.
  41. DURIP: Instrumentation for Vibration Control, Structural Integrity and Stability Augmentation Studies of Rotorcraft Systems, (Army Research Office), (Co-PI with Wereley and Pines ), 1 year (2001-02): (Total Award $185K), Chopra’s Share: $62K
  42. Morphing of rotor blades with magnetic shape memory alloy actuators to actively control vibration and performance, ONR, (MURI Task, PI: Wuttig), 1 years, (2001-2), $100K.
  43. Development of Swashplateless Rotor Using Magnetic Shape Memory Alloys Actuators, ARO/DARPA, 2 years, (2001-4), $375K.
  44. IPA for George Price, (NASA Headquarters), 4 years, (2002-6), $558K
  45. Neural Network Based Robust Individual Blade Controller, (NASA Ames), 2 year (2002-4), $45K
  46. Supplemental UAV and Swashplateless Research, (NRTC), 1 year, (2003-2004), $253K.
  47. Active Pitch Link Technology for Rotorcraft, (MIPS/Techno-Science), 1 year (2003-04), $123K
  48. MURI: Micro Hovering Air Vehicles: Revolutionary Concepts and Navigational Advancements, (Army Research Office), Team Members from UM (Aero, Mech and EE), North Carolina A&T and Australian National University, 17 faculty, 24 research tasks, 22 supported graduate students) 5 years (2004-2009): $5.25M
  49. Design Studies of a Heavy Lift Rotorcraft, (NASA Ames), 1 year (2004-05), $51K
  50. IPA for Dr. Roichenbach, (FAA), 1 years, (2004-05), $38K
  51. Active Pitch Link Technology for Rotorcraft (MIPS/Techno-Science/ARO), Phase II STTR, 2 years (2004-06), $400K
  52. Development of Swashplateless Rotor System (Techno-Science/Army Huntsville), SBR Phase II, 2 years (2004-06), $300K
  53. Helicopter Quieting Program (DARPA/ARO), Team Members UM (Baeder, Chopra, Schmitz) and Stanford Uni., 2 years (2004-06) (Total $3.4M), Chopra Share: $500K.
  54. Evaluation of Test Techniques and Prediction Methodologies for Rotorcraft, (NASA Ames Research Center), 3 years (2005-08), $535K
  55. Aerodynamics and Dynamics of High Speed Coaxial Rotor Systems, (ONR), 3 years, (2006-09), $575K.
  56. Development of Servo-Flap CFD Analysis: (CRI), 3 years, (2005-08), 150K.
  57. Design of Disaster and Emergency Response Module (CRI), 2 years (2005-08), 160K.
  58. Detailed Performance, Wakes, Pressure and Loads for High Speed Single and Coaxial Rotors (Co-I Leishman), NASA (NRA), 4 years (2007-2011), $1.37M
  59. MAST CTA “Center on Microsystem Mechanics” Army Research Lab, Team Members from UM (Aero, Mech), North Carolina A&T, Berkley, Caltech, Georgia Tech and Harvard 18 faculty, 19 research tasks, 26 supported graduate students) 10 years (2008-2018): $23M
  60. DURIP: “Measurement and Autonomous Control tools for the Development of Micro Hovering Air Vehicles,” ARO, one year (2008-09), $150K
  61. Aeromechanics of an Optimized, Actively-Morphing Rotor System,” ONR, 3 years, (2009-12), $300K
  62. DURIP: “Flow and Performance Measurement and Fabrication Tools for the Development of Micro Hovering Air Vehicles,” ARO, one year (2009-2010), $170K.
  63. ONR: “Key Aeromechanics Issues Related to Heavy Lift Rotorcraft,” two years (2010-12), $962K
  64. DURIP: ONR: “Instrumentation for Fabrication and Testing of Mission-Adaptive Actively Morphing Rotor Systems,” one year (2010-11), $187K
  65. Sikorsky: “AATD Active Rotor Program,” two years (2008-10), $150K
  66. NRTC: “Compact Brushless DC Motor System to Actuate Integrated Flaps towards the Development of a Swashplateless Rotor,” 2 years (2008-10), $153K.
  67. NAVAIR: “Slung Load Stabilization in High-Speed Flight,” 2 years (2008-2010), 2010, $200K
  68. NRTC: “Development and Testing of a Swashplateless Rotor in Glenn L. Martin Wind Tunnel with Compact Brushless Motor Actuated Flap for Primary Control,” 3 years (2010-13), $400K
  69. TechnoScience: “Experimental Approaches to Rotor and Dynamic Component Stress,” 2 years (2010-12), $100K
  70. NRTC: “Vertical Lift Research Center of Excellence (VLRCOE),” 5 years (2011-16), $7.5M
  71. Israel Ministry of Defense: “Autonomous Operation of Micro-Helicopters,” 1 years (2011-12), $150K
  72. NRTC: Army AFDD: “CAD-Based Structural Modeling for Advanced Rotors,” 3 years (2013-14), $600K
  73. NAVAIR: “Improved Finite Element in Time Method for Rotorcraft Comprehensive Analysis,” 2 years (2013-16), $150K
  74. Israel Ministry of Defense: “Aeromechanics of Rotorcraft in High Speed Flight,” 2 years (2014-16), $300K
  75. GE: “Engine Vibration due to Helicopter Main Rotor Response,” 3 years (2014-17), $685K.
  76. DURIP: ARO: “Fabrication and Testing of High-Speed Single-Rotor and Compound-Rotor Systems,” 1 year (2014-15), $179K.
  77. NRTC: Army AFDD: “Design Tools for Micro Systems ,” 3 years (2013-14), $225K
  78. Army/Navy/NASA: “Vertical Lift Research Center of Excellence (VLRCOE),” 5 years (2016-21), $7.8M
  79. Army/VTD: “CRA: Vertical Lift Platform Concept Design and Aeromechanics Analysis,” 2 years (2016-18), $0.9M
  80. DURIP: ONR: “Modification of Model Rotor Rig for Testing of High-Speed Advanced Compound Rotorcraft in the Glenn L. Martin Wind Tunnel,” 1 Year (2017-18), 293K

Total External Support = $88.97 Million

Internal Research Support

These include support from MM (Minta-Martin Aeronautical Research Fund), ERC (Engineering Research Center), Graduate School and Dean (College of Engineering).

  1. Dynamic Stability of a Composite Blade Using Finite Element Analysis, (MM), 1 year (1982-83): $20K
  2. Flight Stability Studies of Helicopters – Mast Bumping, (MM), 1 year, (1984-85): $11K
  3. Procurement of Autoclave for Composite Laboratory, (ERC), 1 year (1985): $109K
  4. Analytical and Experimental Investigation of Circulation Controlled Aerodynamics of Cylindrical Bodies, (MM), 1 year, (1985-86): $11K
  5. Identification of Stiffness Coupling Terms for Composite Blades, (MM), 1 year, (1986-87): $12K
  6. Dynamic Testing of Rotor Models in Vacuum Chamber, (MM), 1 year (1988-89): $15K
  7. Cost Share: Instrumentation for Rotorcraft Model Testing, (Graduate School & Dean), 1 year (1988-89): $60K
  8. A Comprehensive Rotorcraft Analysis Code, (MM), 1 year (1989-90): $12K.
  9. Validation of UMARC (University of Maryland Advanced Rotorcraft Code), (MM), 1 year, (1990-91): $17K
  10. A Space Initiative in the Department of Aerospace Engineering, (MM), 1 year, (1990-91): $45K
  11. Cost Share URI: Smart-Structures Technology: Innovations and Applications to Rotorcraft Systems, (Graduate School, Dean & ERC), 3 years (1992-95): $150K
  12. Cost Share: Center for Rotorcraft Education and Research, (Graduate School, Dean & ERC), 3 years, (1992-95): $300K
  13. Cost Share: Instrumentation for Center for Rotorcraft Education and Research, (Graduate School and Dean). 1 years, (1993-94): $95K
  14. Cost Share: Augmentation for Center for Rotorcraft Education and Research, (Graduate School, Dean & ERC), 2 years, (1994-96): $50K
  15. Development of Smart Structures Technology, (MM), 4 years (1991-96): $225K
  16. Cost Share MURI: Innovative Smart Technologies for an Actively Controlled Jet-Smooth Quiet Rotorcraft 5 years, (1996-2001): $175K
  17. Cost Share: Center for Rotorcraft Education and Research, (Graduate School, Dean & Department) 5 years, (1996-2000): $300K
  18. DURIP: Instrumentation for Structural Integrity of Rotorcraft Systems, (Graduate School, Dean and Aero & Mech Dept.), (Co-PI with Wereley, Pines and Sirkis), 1 year, (1996-97): Total $100K, Chopra’s Share: $25K
  19. Travel Support, (Minta-Martin), 3 years, 1997-2000, $6K
  20. Cost Share for Center for Rotorcraft Education and Research, (Graduate School and Dean), 5 years, (2001-6): $550K
  21. DURIP: Instrumentation for Vibration Control, Structural Integrity and Stability Augmentation Studies of Rotorcraft Systems, (Army Research Office), (Co-PI with Wereley and Pines ), Cost Share by Graduate School, Dean and Department, 1 year (2001-02): Total $115K), Chopra’s Share: $38K
  22. Micro Air Vehicle Development, one year (2002-3), $35K
  23. High Speed Computation Facility, (2004), Dean $40K
  24. MURI: Cost Share from Graduate School and Dean, 5 years, (2004-9): $250K
  25. “Center on Microsystem Mechanics”, 10 years, (2008-2018), $2.5M
  26. DURIP Cost Share: 1 year, (2008-09), $50K
  27. DURIP Cost Share: 1 year, (2009-10), $25K
  28. DURIP Cost Share: 1 year, (2010-11), $25K
  29. VLRCOE: Cost Share: 5 years (2011-16), $1M
  30. DURIP Cost Share: 1 year, (2014-15), $16K
  31. VLRCOE: Cost Share: 5 Years (2016-21), $1.2M

Total Internal Support = $7.32 Million