The mechanics of composite materials and structures program at Rensselaer has the benefit of two dedicated composite materials laboratories.
In the Civil and Environmental Engineering Department there is the Mechanics of Materials Research Laboratory, directed by Dr. G.J.Dvork, chairman of the department. This laboratory is equipped with two servo-hydraulic testing machines. There is a tension torsion-internal pressure and a 250 kN tension material testing machine. These machines are linked to a computer for precise control and data retrieval. Recent emphasis is on characterization of the behavior of high temperature metal matrix and ceramic matrix composites. New high temperature facilities, which are available for graduate studies, include resistance heating and induction heating setups along with necessary instrumentation for tests up to 1400 degrees C. These are being used for experimental investigations in the area of fracture, inelastic behavior, and fatigue of fibrous composites.
The Composite Materials and Structures Laboratory, which was founded in 1976 and is directed by Dr. S.Sternstein, trains students in the design, fabrication, and testing of composite materials. With the hands-on experience that Rensselaer graduates obtain, they are qualified for entry to engineering positions which specialize in the application of composite materials.
The environmental engineering program works closely with Rensselaer's Fresh Wather Institute, which has analytical laboratories on campus and maintains a field station on Lake George. The field station has laboratory facilities and field equipment, including two research vessels.
The Structural Testing Laboratory is equipped with a variety of testing machines that can apply tensile, compressive, and torsional loadings to structures. The laboratory contains a humidity room, a fatigue testing machine, torsional and flexual testing machine, and one 60K-, one 100K- and one 400K-universal testing machine.
The Structural Models Laboratory has facilities for fabricating and constructing structural models, along with instrumentation for analysis and testing.
The laboratory is utilized mainly for advanced research aiming to develop infrastructure management systems, expert systems, databases, and information modeling techniques for management of transportation infrastructure. The facility is staffed by a research engineer, research associates, and graduate and undergrauate students participating in infrastructure research projects.
Faculty and staff maintain local working relationships with personnel at the New York State Thruway Authority and New York State Department of Transportation, in addition to international contacts in Switzerland and Canada. These operational enviornments provide real-world data for system development, and serve as test beds for research products.
The Center for Infrastructure & Transportation Studies
A closed loop servo-hydrulic axial-torsional loading system with a 5,500lb. axial acuator and a 1,00 in.-lb. torsional actuator, can perform tests in both axial and torsional modes, alone or combined, in phase or at an arbirary phase angel. The soil specimens are placed inside specially desinged triaxial cells. Either mode can be applied to the soil monotonically or cyclically, in stress or strain control. Also, in either mode the load or displacement can be held constant while the loading is varied in the other mode. Modern, dedicated computerized data acquisition and control capablities are used.
The system has been applied to study the cyclic undrained behavior of saturated sand, liquefaction and flow failure during earthquakes, and constitutive relation for cohesionless soil. Recent projects have included the re-evaluation of the flow slide in one of the slopes of the Lower San Fernando Dam in California during the 1971 earthquake, the development of a new method to predict permanent ground deformations due to earthquakes, and a study of yield surfaces in dry sand during cyclic loading.
A Norwegian Geotecnical Institute direct simple shear device has been modified by integrating it with the servo-hydraulic closed loop system mentioned above. This allows it to perform stress or strain controlled cyclic tests in a variety of wave forms. It has been used to study the response of marine clays and silts during earthquake and sea wave loading.
Recent additons to the laboratory include the geotechnical centrifuge (described beblow); a resonant column device for measurement of wave velocity/modulus and internal damping of the soil; a number of personal computers, computer terminal, wrostation, and peripherals located in a newly renovated computer room; and in situ shaking equipment.
The in situ equipment is used to measure the vibration characteristics of full scale soil and soil-structure systems in the field, such as earth and reinfored-earch walls, dams, bredges, etc. This is used to evaluate the response of those civil engineering facilities when subjected to earthquake loading. Nondestructive tests are conducted using either impact with a specially calibrated hammer, or steady-stete vibration with a 5,000lb.force harmonic exciter recently designed and constructed at Rensselaer. Eight channels of high-speed data acquisition are availble.
Moreover, the transportation faculty maintain close working relationships with a large number of state and federal agencies to facilitate field experiments. These include the New York State Departemnt of Transportation, the Capital Distric Trnasit Authority, the Federal Highway Administration, the City of Troy, the City of Albany, and Sandia National Laboratories.