Provided are methods and apparatus for determining a coefficient of thermal expansion (CTE) of at least a portion of a test object. An example provided method includes (i) producing information describing a reference image of the test object portion during low-temperature excitation; (ii) heating the test object portion to a higher temperature; (iii) measuring a change in temperature of the test object portion; (iv) producing information describing an image of thermal change in displacement of the test object portion at the higher temperature; (v) comparing the information describing the image of thermal change in displacement of the test object portion at the higher temperature to the information describing the reference image to produce strain information describing heating-induced changes in strain in the test object portion; and (vi) producing CTE information by correlating the strain information with the change in temperature of the test object portion.

A triple bubbler system includes a first fluid probe, a second fluid probe, a third fluid probe, a gas source operably coupled to the first fluid probe, the second fluid probe, and the third fluid probe and configured to meter gas through the first fluid probe, the second fluid probe, and the third fluid probe to form bubbles at tips of each of the first fluid probe, the second fluid probe, and the third fluid probe, and a cover member disposed over the tips of the first, second, and third fluid probes and configured to at least partially prevent bubbles formed and escaping the tips of the first, second, and third fluid probes from interfering with other bubbles formed at each other tips. The bubbler system includes a thermocouple having a plurality of junctions disposed along an axis parallel to longitudinal axes of the first, second, and third fluid probes.

A method for determining an expansion coefficient of a test material comprises: receiving first image data of a compound material, wherein the compound material comprises a plate and a layer of the test material, which is attached to the plate; receiving second image data of the compound material, which has been exposed to an environmental condition, before the second image data has been recorded; determining a measured deformation of the compound material by comparing the first image data and the second image data; and performing a simulated deformation of a model of the compound material exposed to the environmental condition and determining the expansion coefficient of the test material by varying the expansion coefficient until the simulate deformation conforms to the measured deformation.

A method for determining an expansion coefficient of a test material comprises: receiving first image data of a compound material, wherein the compound material comprises a plate and a layer of the test material, which is attached to the plate; receiving second image data of the compound material, which has been exposed to an environmental condition, before the second image data has been recorded; determining a measured deformation of the compound material by comparing the first image data and the second image data; and performing a simulated deformation of a model of the compound material exposed to the environmental condition and determining the expansion coefficient of the test material by varying the expansion coefficient until the simulate deformation conforms to the measured deformation.

Dilatometer systems for measuring characteristics of material samples are disclosed. In one embodiment, a dilatometer system includes a reactor adapted to receive the test sample, a density trap in fluid communication with the reactor, a first fluid selectively filling the reactor and a portion of the density trap, and a second fluid selectively filling a portion of the density trap. The first fluid and the second fluid are immiscible with one another and selectively form an immiscible fluid boundary in the density trap. The dilatometer system further includes a heater that selectively heats the first fluid.

Dilatometer systems for measuring characteristics of material samples are disclosed. In one embodiment, a dilatometer system includes a reactor adapted to receive the test sample, a density trap in fluid communication with the reactor, a first fluid selectively filling the reactor and a portion of the density trap, and a second fluid selectively filling a portion of the density trap. The first fluid and the second fluid are immiscible with one another and selectively form an immiscible fluid boundary in the density trap. The dilatometer system further includes a heater that selectively heats the first fluid.

A triple bubbler system includes a first fluid probe, a second fluid probe, a third fluid probe, an gas source operably coupled to the first fluid probe, the second fluid probe, and the third fluid probe and configured to meter gas through the first fluid probe, the second fluid probe, and the third fluid probe to form bubbles at tips of each of the first fluid probe, the second fluid probe, and the third fluid probe, and a cover member disposed over the tips of the first, second, and third fluid probes and configured to at least partially prevent bubbles formed and escaping the tips of the first, second, and third fluid probes from interfering with other bubbles formed at each other tips. The bubbler system includes a thermocouple having a plurality of junctions disposed along an axis parallel to longitudinal axes of the first, second, and third fluid probes.

A magnetic core structure for a Linear Variable Differential Transducer (LVDT) comprising an elongate core of magnetic material mounted within a protective tube and means for positioning the core within the protective tube, the means for positioning comprising a ball provided within the protective tube at one end of the core, the ball being formed of an elastic material having a coefficient of thermal expansion selected to compensate the difference in elongation between magnetic core structure components caused by thermal expansion.

A magnetic core structure for a Linear Variable Differential Transducer (LVDT) comprising an elongate core of magnetic material mounted within a protective tube and means for positioning the core within the protective tube, the means for positioning comprising a ball provided within the protective tube at one end of the core, the ball being formed of an elastic material having a coefficient of thermal expansion selected to compensate the difference in elongation between magnetic core structure components caused by thermal expansion.

A strain detecting device includes a sensor portion and a covering elastic deformation member. The elastic deformation member generates heat when compressed and absorbs heat when expanded, resulting in heat flux. The sensor portion includes first and second heat flux sensors, each of which has first and second sensor surfaces formed opposite to each other. Each sensor outputs a strain-indicating signal of a polarity when the heat flux passes through the sensor, from the first sensor surface to the second sensor surface, and outputs a strain-indicating signal of an opposite polarity when the heat flux passes through the sensor in reverse, from the second sensor surface to the first sensor surface. The first sensor surfaces are opposed to each other across a heat absorbing member interposed between the sensors. The sensor portion generates signals based on the heat flux generated by deformation of the elastic deformation member.