Mechanics and Vibration Research at the School of Mechanical Engineering, Purdue University
The Mechanics and Vibrations Area in the School of Mechanical Engineering conducts research on linear and nonlinear vibrations, dynamics, and acoustics, with applications in high temperature materials, advanced materials, biomechanics and biological materials, mechanics of manufacturing processes, noise and vibration control in suspensions, brakes, and other automotive/aerospace systems, experimental model identification for multi-body systems, and structural health monitoring for prognosis of ground vehicles, aircraft, spacecraft, weapon systems, and other mechanical components.
Faculty and students in the Mechanics and Vibrations Area conduct both basic and applied research. Basic research advances our fundamental understanding of both experimental and theoretical mechanics. Applied research may, for example, involve the development of engines, turbines, compressors and vehicles that are more compact and lighter, as well as more efficient and longer lasting. Applied research could also involve the development of measurement and prediction methodologies for assessing the destructive effects of operating loads and the environment in mechanical materials and systems, for example, in automotive suspensions and body armor.
Mechanics and Vibrations at Purdue University are also represented by faculty groups in the Schools of Aeronautics and Astronautics and Civil Engineering, among others. The research on the biomechanics of biological tissues and cell-extracellular interactions, for example, is conducted in collaboration with researchers in the Department of Biomedical Engineering as well as in the School of Veterinary Medicine.
Members of the Mechanics and Vibration Area faculty have conducted research related to other areas in the School, and members in other areas conduct research related to mechanics and vibration. For example, acoustics research, which is typically related to vibrations may be reported under the Acoustics and Noise Control Area. The Design Area faculty works in machinery dynamics and vibrations, dynamics of machine elements, finite-element analysis and computer simulation of dynamic processes. The faculty of the Systems, Measurement and Control Area also contributes to mechanics and vibrations research, as, for example, in the area of metal cutting and tool chatter.
Faculty and students conduct their experimental research in Mechanics primarily at the Ray W. Herrick Laboratories, which is well equipped for acoustic, vibration, stress and general dynamic measurements. Major facilities at the Herrick Labs include a two post road simulator for full scale vehicle dynamic testing, spring-loaded drop tower for 600 ft-lb impact tests, reverberation, anechoic, and semi-anechoic acoustic rooms, combined vibration-acoustic-thermal test chamber for simulating severe launch and engine exhaust environments, and hundreds of channels of dynamic sensing and data acquisition equipment. The Mechanical Engineering building also offers experimental facilities for mechanics of materials research in thermal stresses and biomechanics. These facilities include a CO2 laser with an infrared pyrometer, telescopic microscope, high-resolution VCR and acoustic emission system for nondestructive detection of thermal fractures. Researchers investigate tissue engineering by using a Universal Testing Machine with recirculating water chamber and constant temperature bath system, as well as other custom-designed systems.
Research projects in the Mechanics and Vibration Area are either funded by governmental agencies or industry. Governmental agencies, such as the National Science Foundation, the National Aeronautics and Space Administration, and the U.S. Department of Defense, may fund both basic and applied research. On the other hand, funds from industry or industrial consortia are usually restricted to applied research. Industry support gives graduate students the advantage of close contact with experts from sponsoring companies, and often spawns new ideas also in basic research. Support through special student or faculty fellowships often leads to new research directions in new applications. Past and current examples of such cooperation include the study of the vibration and dynamics of shells, failure analysis of composite and dissimilar materials, rotor dynamics, gas pulsation in pipelines, valve flutter, brake squeal and thermal barrier ceramic coatings.
Typical Current and Past Research Projects
To give a flavor of the interests of the faculty in Mechanics and Vibration, some current and also some past projects are listed below:
- Vibration and noise in spiral bevel gears.
- Experimental and analytical modeling of gearbox dynamics including the modal response of casing, bearings and gear teeth.
- Response of nonlinear, multidegree-of-freedom weakly coupled cyclic systems. Techniques from equivariant bifurcation theory shed light on the classification of the various types of periodic solutions and their bifurcations.
- Experimental and numerical investigations of the dynamic properties of rubber and plastic materials.
- Experimental and analytical studies of functionally graded ceramic thermal barrier coatings used in Diesel engines.
- Thermal shock response of precracked thermal barrier coatings used in gas turbines.
- Nonlinear vibrations of multidegree-of-freedom mechanical systems resulting from internal and external resonances (for example, centrifugal and spherical pendulums and dynamic vibration absorbers).
- The mechanical behavior of biological materials and their compatibility as tissue graft material.
- The remodeling of patellar tendons augmented with small intestinal submucosa (SIS).
- The rate of remodeling of Achilles’ tendons in the presence of SIS under varying exercise regimes.
- An analysis method for predicting the space and time averaged high-frequency vibration behavior of simple and built-up structures.
- Wind tunnel measurements and analysis of flow-induced sound and vibration problems in turbomachinery, ventilation fans and vehicles.
- The biomechanics of cell-extracellular matrix interactions.
- Wave propagation in tires modeled as continuous structures and approached by wave number-based methods for identifying wave dispersion characteristics.
- Forced and free vibration response of tires.
- Study of the onset of squeal vibrations in drum-brake systems. Brake squeal is a noise source, which may also interfere with the performance of the brake.
- Vibration response of nonlinear systems as they pass through resonance.
- Friction-induced dynamics of the engagement of an automatic transmission clutch.
- Vibratory systems identification methods in the time and frequency domain for both linear and nonlinear mechanical systems with application to seat foam, tire-suspensin systems, and rivited structures.
- Diagnostic and prognostic methods that integrate mechanics-based models with experimental system identification techniques to identify damage and its evolution in structural materials and components. Applications of these methods include ground vehicle suspensions/wheels/tires, spacecraft metallic, ceramic, carbon-carbon thermal protection systems, and other mechanical systems including body armor and blast structures.
- System of dynamic systems analysis of hybrid systems using event-driven simulations with application to naval ships, which contain hydraulic, electric, mechanical machinery and crew members who utilize this machinery.
- Mechanics of the spine and spine implants.
- Study of the solid mechanics and fluid mechanics of hierarchical materials.
- Biomechanics of the human eye.
- Human injury, with particular emphasis on the knee, head, and spinal cord.