Mechanical Engineering
220 S. W. Mudd, MC 4703,
212-854-2965
www.columbia.edu/cu/mechanical
Mechanical engineering is a diverse subject that derives its breadth from the need to design and manufacture everything from small individual parts/devices (e.g., micro-scale sensors, inkjet printer nozzles) to large systems (e.g., spacecraft and machine tools). The role of a mechanical engineer is to take a product from an idea to the marketplace. In order to accomplish this, a broad range of skills are needed. The particular
skills in which the mechanical engineer acquires deeper knowledge are the
ability to understand the forces and the thermal environment that a product, its parts, or its subsystems will encounter; design them for functionality, aesthetics, and the ability to withstand the forces and the thermal environment they will be subjected to; determine the best way to manufacture them and ensure they will operate without failure. Perhaps the one skill that is the mechanical engineer’s exclusive domain is the ability to analyze and design objects and systems with motion.
Since these skills are required for virtually everything that is made, mechanical engineering is perhaps the broadest and most diverse of engineering disciplines. Hence mechanical engineers play a central role in such industries as automotive (from the car chassis to its every subsystem—engine, transmission, sensors); aerospace (airplanes, aircraft engines, control systems for airplanes and spacecraft); biotechnology (implants, prosthetic devices, fluidic systems for pharmaceutical industries); computers and electronics (disk drives, printers, cooling systems, semiconductor tools); microelectromechanical systems, or MEMS (sensors, actuators, micro power generation); energy conversion (gas turbines, wind turbines, solar energy, fuel cells); environmental control (HVAC, air-conditioning, refrigeration, compressors); automation (robots, data/image acquisition, recognition, and control); manufacturing (machining, machine tools, prototyping, microfabrication).
To put it simply, mechanical engineering deals with anything that moves, including the human body, a very complex machine. Mechanical engineers learn about materials, solid and fluid mechanics, thermodynamics, heat transfer, control, instrumentation, design, and manufacturing to realize/ understand mechanical systems. Specialized mechanical engineering subjects include biomechanics, cartilage tissue engineering, energy conversion, laser-assisted materials processing, combustion, MEMS, microfluidic devices, fracture mechanics, nanomechanics, mechanisms, micro-power generation, tribology (friction and wear), and vibrations. The American Society of Mechanical Engineers (ASME) currently lists thirty-six technical divisions, from advanced energy systems and aerospace engineering to solid waste engineering and textile engineering.
The breadth of the mechanical engineering discipline allows students a variety of career options beyond some of the industries listed above. Regardless of the particular future path they envision for themselves after they graduate, their education would have provided them with the creative thinking that allows them to design an exciting product or system, the analytical tools to achieve their design goals, the ability to meet several sometimes conflicting constraints, and the teamwork needed to design, market, and produce a system. These skills also prove to be valuable in other endeavors and can launch a career in medicine, law, consulting, management, banking, finance, and so on.
For those interested in applied scientific and mathematical aspects of the discipline, graduate study in mechanical engineering can lead to a career of research and teaching.
Current Research Activities
Current research activities in the Department of Mechanical Engineering are in the areas of controls and robotics, energy and micropower generation, fluid mechanics, heat/mass transfer, mechanics of materials, manufacturing, material processing, MEMS, nanotechnology, and orthopedic biomechanics.
Biomechanics and Mechanics of Materials. Some of the current research in biomechanics is concerned with the application of continuum theories of mixtures to problems of electromechanical behavior of soft biological tissues, contact mechanics, lubrication of diarthrodial joints, and cartilage tissue engineering. (Ateshian)
In the area of the mechanics of materials, research is performed to better understand material constitutive behavior at the micro- and mesolength scales. This work is experimental, theoretical, and computational in nature. The ultimate goal is to formulate constitutive relationships that are based on physical concepts rather than phenomenology, as in the case of plasticity power-law hardening. In addition, the role that the constitutive relations play in the fracture and failure of materials is emphasized. (Kysar)
Control, Design, and Manufacturing. Control research emphasizes iterative learning control (ILC) and repetitive control (RC). ILC creates controllers that learn from previous experience performing a specific command, such as robots on an assembly line, aiming for high-precision mechanical motions. RC learns to cancel repetitive disturbances, such as precision motion through gearing, machining, satellite precision pointing, particle accelerators, etc. Time optimal control of robots is being studied for increased productivity on assembly lines through dynamic motion planning. Research is also being conducted on improved system identification, making mathematical models from input-output data. The results can be the starting point for designing controllers, but they are also studied as a means of assessing damage in civil engineering structures from earthquake data. (Longman)
Robotics and mechanism synthesis research focuses on the analysis of kinematic relationship, optimization, and design of linkages and spatial mechanisms, and the development of novel robotic mechanical architectures. These new robotic architectures include parallel robots, hybrid robots, snakelike robots, and flexible and flexure-based robots. The theoretical aspects of this research include applications of line geometry tools and screw theory for analysis and synthesis of robotic devices, applications of actuation redundancy and kinematic redundancy for stiffness control, and applications of algebraic geometry methods for robot synthesis. The applied aspects of this research include task-based design and construction of new devices/robots for robotic medical assistance in the surgical arena. (Simaan)
In the area of advanced manufacturing processes and systems, current research concentrates on laser materials processing. Investigations are being carried out in laser micromachining; laser forming of sheet metal; microscale laser shock-peening, material processing using improved laser-beam quality. Both numerical and experimental work is conducted using state-of-the-art equipment, instruments, and computing facilities. Close ties with industry have been established for collaborative efforts. (Yao)
Energy, Fluid Mechanics, and Heat/Mass Transfer. In the area of energy, one effort addresses the design of flow/mass transport systems for the extraction of carbon dioxide from air. Another effort addresses the development of distributed sensors for use in micrositing and performance evaluation of energy and environmental systems. The design and testing of components and systems for micropower generation is part of the thermofluids effort as well as part of the MEMS effort. (Modi)
In the area of fluid mechanics, study of low-Reynolds-number chaotic flows
is being conducted both experimentally and numerically, and the interactions with molecular diffusion and inertia are presently being investigated. Other areas of investigation include the fluid mechanics of inkjet printing, drop on demand, the suppression of satellite droplets, shock wave propagation, and remediation in high-frequency printing systems. (Attinger, Modi)
In the area of microscale transport phenomena, current research is focused on understanding the transport through interfaces, as well as the dynamics of interfaces. For instance, an oscillating microbubble creates a microflow pattern able to attract biological cells. High-speed visualization is used together with innovative laser measurement techniques to measure the fluid flow and temperature field with a very high resolution. (Attinger).
MEMS and Nanotechnology. In these areas, research activities focus on power generation systems, nanostructures for photonics, fuel cells and photovoltaics, and microfabricated adaptive cooling skin and sensors for flow, shear, and wind speed. Basic research in fluid dynamics and heat/mass transfer phenomena at small scales also support these activities. (Attinger, Hone, Lin, Modi, Wong)
Research in the area of nanotechnology focuses on nanomaterials such as nanotubes and nanowires and their applications, especially in nanoelectromechanical systems (NEMS). A laboratory is available for the synthesis of carbon nanotubes and semiconductor nanowires using chemical vapor deposition (CVD) techniques and to build devices using electron-beam lithography and various etching techniques. This effort will seek to optimize the fabrication, readout, and sensitivity of these devices for numerous applications, such as sensitive detection of mass, charge, and magnetic resonance. (Hone, Wong, Modi)
Research in the area of optical nanotechnology focuses on devices smaller than the wavelength of light, for example, in photonic crystal nanomaterials and NEMS devices. A strong research group with facilities in optical (including ultrafast) characterization, device nanofabrication, and full numerical intensive simulations is available. Current efforts include silicon nanophotonics, quantum dot interactions, negative refraction, dramatically enhanced nonlinearities, and integrated optics. This effort seeks to advance our understanding of nanoscale optical physics, enabled now by our ability to manufacture, design, and engineer precise subwavelength nanostructures, with derived applications in high-sensitivity sensors, high-bandwidth data communications, and biomolecular sciences. Major ongoing collaborations across national laboratories, industrial research centers, and multiuniversities support this research. (Wong)
In the area of microscale power generation, efforts are dedicated to build a micromotor using acoustic energy amplified by a microbubble. (Attinger)
Research in BioMEMS aims to design and create MEMS and micro/nanofluidic systems to control the motion and measure the dynamic behavior of biomolecules in solution. Current efforts involve modeling and understanding the physics of micro/ nanofluidic devices and systems, exploiting polymer structures to enable micro/nanofluidic manipulation, and integrating MEMS sensors with microfluidics for measuring physical properties of biomolecules. (Lin)
Biological Engineering and Biotechnology. Active areas of research in the musculoskeletal biomechanics laboratory include theoretical and experimental analysis of articular cartilage mechanics; theoretical and experimental analysis of cartilage lubrication, cartilage tissue engineering, and bioreactor design; growth and remodeling of biological tissues; cell mechanics; and mixture theory for biological tissues with experiments and computational analysis (Ateshian).
The Hone group is involved in a number of projects that employ the tools of micro- and nano-fabrication toward the study of biological systems. With collaborators in biology and applied physics, the group has developed techniques to fabricate metal patterns on the molecular scale (below 10 nanometers) and attach biomolecules to create biofunctionalized nanoarrays. The group is currently using these arrays to study molecular recognition, cell spreading, and protein crystallization. Professor Hone is a co-PI of the NIH-funded Nanotechnology Center for Mechanics in Regenerative Medicine, which seeks to understand and modify at the nanoscale force- and geometry-sensing pathways in health and disease. The Hone group fabricates many of the tools used by the center to measure and apply force on a cellular level (Hone).
Microelectromechanical systems (MEMS) are being exploited to enable and facilitate the characterization and manipulation of biomolecules. MEMS technology allows biomolecules to be studied in well-controlled micro/nanoenvironments of miniaturized, integrated devices, and may enable novel biomedical investigations not attainable by conventional techniques. The research interests center on the development of MEMS devices and systems for label-free manipulation and interrogation of biomolecules. Current research efforts primarily involve microfluidic devices that exploit specific and reversible, stimulus-dependent binding between biomolecules and receptor molecules to enable selective purification, concentration, and label-free detection of nucleic acid, protein, and small molecule analytes; miniaturized instruments for label-free characterization of thermodynamic and other physical properties of biomolecules; and subcutaneously implantable MEMS affinity biosensors for continuous monitoring of glucose and other metabolites (Lin).
The advanced robotics and mechanism application lab (ARMA) is focused on surgical intervention using novel robotic architectures. Examples of these architectures include flexible snakelike robots, parallel robots, and cooperative robotic systems. The current research activity is focused on providing safer and deeper interaction with the anatomy using minimally invasive approaches, surgery through natural orifices, surgical task planning based on dexterity and performance measures, and manipulation of flexible organs. The ongoing funded research projects include NIH-funded grants on designing next-generation robotic slaves for incisionless surgical intervention (surgery through natural opening); minimally invasive surgery for the throat and upper airways; image-guided insertable robotic platforms for less invasive surgery (surgery that is carried out using a single incision in the abdomen); and robotic assistance for cochlear implant surgery (NSF funded, Simaan).
Mass radiological triage is critical after a large-scale radiological event because of the need to identify those individuals who will benefit from medical intervention as soon as possible. The goal of the ongoing NIH-funded research project is to design a prototype of a fully automated, ultra high throughput biodosimetry. This prototype is supposed to accommodate multiple assay preparation protocols that allow the determination of the levels of radiation exposure that a patient received. The input to this fully autonomous system is a large number of capillaries filled with blood of patients collected using finger sticks. These capillaries are processed by the system to distill the micronucleus assay in lymphocytes, with all the assays being carried out in situ in multi-well plates. The research effort on this project involves the automation system design and integration including hierarchical control algorithms, design and control of custom built robotic devices, and automated image acquisition and processing for sample preparation and analysis (Simaan, Yao).
A technology that couples the power of multidimensional microscopy (three spatial dimensions, time, and multiple wavelengths) with that of DNA array technology is investigated in an NIH-funded project. Specifically, a system is developed in which individual cells selected on the basis of optically detectable multiple features at critical time points in dynamic processes can be rapidly and robotically micromanipulated into reaction chambers to permit amplified DNA synthesis and subsequent array analysis. Customized image processing and pattern recognition techniques are developed, including Fisher’s linear discriminant preprocessing with neural net, a support vector machine with improved training, multiclass cell detection with error correcting output coding, and kernel principal component analysis (Yao).
Facilities for Teaching and Research
The undergraduate laboratories, occupying an area of approximately 6,000 square feet of floor space, are the site of experiments ranging in complexity from basic instrumentation and fundamental exercises to advanced experiments in such diverse areas as automatic controls, heat transfer, fluid mechanics, stress analysis, vibrations, microcomputer-based data acquisition, and control of mechanical systems.
Equipment includes microcomputers and microprocessors, analog-to-digital and digital-to-analog converters, lasers and optics for holography and interferometry, a laser-Doppler velocimetry system, a Schlieren system, dynamic strain indicators, a servohydraulic material testing machine, a photoelastic testing machine, an internal combustion engine, a dynamometer, subsonic and supersonic wind tunnels, a cryogenic apparatus, computer numerically controlled vertical machine centers (VMC), a coordinate measurement machine (CMM), and a rapid prototyping system. A CNC wire electrical discharge machine (EDM) is also available for the use of specialized projects for students with prior arrangement. The undergraduate laboratory also houses experimental setups for the understanding and performance evaluation of a complete small steam power generation system, a heat exchanger, and a compressor. Part of the undergraduate laboratory is a staffed machine shop with machining tools such as standard vertical milling machines, engine and bench lathes, programmable surface grinder, bandsaw, drill press, tool grinders, and a power hacksaw. The shop also has a tig welder.
A mechatronics laboratory affords the opportunity for hands-on experience with microcomputer-embedded control of electromechanical systems. Facilities for the construction and testing of analog and digital electronic circuits aid the students in learning the basic components of the microcomputer architecture. The laboratory is divided into work centers for two-person student laboratory teams. Each work center is equipped with several power supplies (for low-power electronics and higher power control), a function generator, a multimeter, a protoboard for building circuits, a microcomputer circuit board (which includes the microcomputer and peripheral components), a microcomputer programmer, and a personal computer that contains a data acquisition board. The data acquisition system serves as an oscilloscope, additional function generator, and spectrum analyzer for the student team. The computer also contains a complete microcomputer software development system, including editor, assembler, simulator, debugger, and C compiler. The laboratory is also equipped with a portable oscilloscope, an EPROM eraser (to erase microcomputer programs from the erasable chips), a logic probe, and an analog filter bank that the student teams share, as well as a stock of analog and digital electronic components.
The department maintains a modern computer-aided design laboratory equipped with fifteen Silicon Graphics workstations and software tools for design, CAD, FEM, and CFD.
The research facilities are located within individual or group research laboratories in the department, and these facilities are being continually upgraded. To view the current research capabilities please visit the various laboratories within the research section of the department Web site. The students and staff of the department can, by prior arrangement, use much of the equipment in these research facilities. Through their participation in the NSF-MRSEC center, the faculty also have access to shared instrumentation and the clean room located in the Shapiro Center for Engineering and Physical Science Research. Columbia University’s extensive library system has superb
scientific and technical collections. E-mail and computing services are maintained by Columbia University Information Technology (CUIT) .