Abstract: A composite material is provided that includes a matrix material, and a plurality of deflectable elements or “machines” disposed in the matrix material, the machines acting to modify one or more physical properties of the composite material in response to forces acting upon the composite material. Preferably, the machines have an elongate shape defining a longitudinal axis, which are disposed within the matrix material in a predetermined array. The elongate members have an asymmetrical cross-section which is deflectable between first and second shapes, and consequently the composite material exhibits different physical properties because the elongate members deflect between the first and second shapes. The machines may include a variety of asymmetrical cross-sections, such as a generally “Z” shape, an hourglass shape, a cantilever shape or a leaf spring shape.

Abstract: A composite material is provided that includes a matrix material, and a plurality of deflectable elements or “machines” disposed in the matrix material, the machines acting to modify one or more physical properties of the composite material in response to forces acting upon the composite material. Preferably, the machines have an elongate shape defining a longitudinal axis, which are disposed within the matrix material in a predetermined array. The elongate members have an asymmetrical cross-section which is deflectable between first and second shapes, and consequently the composite material exhibits different physical properties because the elongate members deflect between the first and second shapes. The machines may include a variety of asymmetrical cross-sections, such as a generally “Z” shape, an hourglass shape, a cantilever shape or a leaf spring shape.

Abstract: A glass transition temperature Tg measurement system includes a probe point penetrating into a sample under test that has been heated by a heater to a temperature where the sample undergoes a phase change from a solid to a semisolid. A thermocouple is used to measure the temperature while a motion transducer is used to measure the amount of penetration. The penetration amount sharply increases at the glass transition temperature. A portable unit can be used in the field to test the Tg properties of various composite materials used, for example, in structures including buildings and bridges.

Abstract: A heater preferably having a plurality of equally spaced heating elements, such as heating lamps, provides a uniform heat radiation pattern for quickly and uniformly heating a large surface area using motor controlled wheels for translating the heater at a constant rate of speed across the surface of a structure in a desired pattern. The heater having a handle for operator manipulation for guiding and turning the heater in the desired pattern. The heater, having a wide lateral distance for radiating a wide uniform radiation pattern is suitable for thermographic application for imaging the heated surface and detecting subsurface defects in the structure, such as composite overwrapped concrete bridge and building structures subject where debonding of the composite/concrete interface is a concern.

Abstract: A passive strain gauge of brittle carbon fibers are aligned along an elongated length and encapsulated in an epoxy matrix to emit acoustic emissions when under stress exerted along the length of the gauge. The gauge can be mounted onto and along a mounted direction upon a structure in line with the carbon fibers which retain a state indicating peak stress along the mounted direction. When removed from the structure, the gauge can be monitored during stress testing by applying an increasing load along the length to determine the amount of peak strain exerted upon the structure which is the strain when the gauge begins to emit acoustic emissions. The strain gauge is well suited for mounting to bridges and buildings which are likely to be subjected to stress events such as an earthquakes for determining the amount of stress exerted upon the structure during the stress inducing event.

Abstract: A technique for impregnating a fluid so that the impregnated fluid retains information about the highest pressure that has ever been exerted on it. This technique is particularly useful where normal pressure measurement methods are not practical.

Abstract: Apparatus for detecting acoustic emissions from metal matrix wire allows on-line measurement of the transverse strength of the wire as it is moving through its manufacturing process. A series of end and middle rollers guide the wire and form a bend in it. The location of the bend in the wire is maintained in contact with a liquid bath which, in turn, is contacted by the sensing surface of an acoustic transducer. Acoustic emissions from breaking of the fiber-matrix interface of the wire are transmitted by the bath and detected by the transducer.