Methods and apparatus are disclosed to determine material parameters of a turbine rotor. An example apparatus includes a rotor geometry determiner to determine a geometry of the rotor, a node radius calculator to calculate radial node locations of radial nodes including a first radial node, a thermocouple interface to record first temperature values over an interval, a first thermal stress calculator to calculate first thermal stress values at one or more of the radial nodes over the interval, a node temperature calculator to calculate second temperature values at respective internal nodes of the first radial node, a reference value lookup to lookup first material parameter information, a second thermal stress calculator to determine second thermal stress values, a thermal stress comparator to calculate a difference between the thermal stress values, and, in response to the difference not satisfying a threshold, a material parameter adjuster to determine material parameters.

Methods and apparatus are disclosed to determine material parameters of a turbine rotor. An example apparatus includes a rotor geometry determiner to determine a geometry of the rotor, a node radius calculator to calculate radial node locations of radial nodes including a first radial node, a thermocouple interface to record first temperature values over an interval, a first thermal stress calculator to calculate first thermal stress values at one or more of the radial nodes over the interval, a node temperature calculator to calculate second temperature values at respective internal nodes of the first radial node, a reference value lookup to lookup first material parameter information, a second thermal stress calculator to determine second thermal stress values, a thermal stress comparator to calculate a difference between the thermal stress values, and, in response to the difference not satisfying a threshold, a material parameter adjuster to determine material parameters.

Apparatus and method of characterizing a material. A sample of a material to be characterized is placed into a thermomechanical analyzer (TMA) instrument, the material sample being a cylindrically- or rectangularly-shaped pellet having parallel top and bottom faces. The TMA has a measurement probe with a single buffer rod intermediate an ultrasound transducer and the top face of the material sample. Ultrasound waves are transmitted through the buffer rod and the top face of the material sample. Signals from the ultrasound waves passing through the material sample are received using a receiving sensor below the bottom face of the material sample. The TMA instrument is then used to control the temperature and forces applied to the material sample and to measure changing length of the material sample. Finally, the ultrasonic attenuation and velocity properties of the material are calculated as a function of the material sample length measurement and received ultrasound signals.

Apparatus and method of characterizing a material. A sample of a material to be characterized is placed into a thermomechanical analyzer (TMA) instrument, the material sample being a cylindrically- or rectangularly-shaped pellet having parallel top and bottom faces. The TMA has a measurement probe with a single buffer rod intermediate an ultrasound transducer and the top face of the material sample. Ultrasound waves are transmitted through the buffer rod and the top face of the material sample. Signals from the ultrasound waves passing through the material sample are received using a receiving sensor below the bottom face of the material sample. The TMA instrument is then used to control the temperature and forces applied to the material sample and to measure changing length of the material sample. Finally, the ultrasonic attenuation and velocity properties of the material are calculated as a function of the material sample length measurement and received ultrasound signals.

To provide a piezoelectric body film that can suppress decrease in the piezoelectric constant d31, a method of producing a piezoelectric body film, and a piezoelectric body device. A piezoelectric body film comprising a fluororesin as a piezoelectric material, the fluororesin containing, as a main constituent unit, a repeating unit derived from vinylidene fluoride, a piezoelectric constant d31 of the piezoelectric body film being 20 pC/N or greater, and an extrapolated onset temperature at start of shrinkage determined by TMA measurement being not lower than 90° C. and not higher than 115° C. The difference between piezoelectric constants d31 measured before and after heating the piezoelectric body film at 100° C. for 24 hours relative to the piezoelectric constant d31 before the heating for 24 hours is 20% or less.

A measuring apparatus of bulk viscosity includes a temperature-controlling cylinder having a test chamber for holding a molding material and at least one piston configured to seal an opening of the temperature-controlling cylinder. The temperature-controlling cylinder and the at least one piston are configured for measuring pressures, specific volumes and temperatures (PVT) of the molding material by applying a plurality of cooling rates to the molding material inside the testing chamber under an isobaric environment, or applying a plurality of mechanical pressures to the molding material inside the testing chamber under an isothermal environment. The measuring apparatus further includes a process module configured for deriving a plurality of parameters in relation to the pressures, specific volumes and temperatures (PVT) of the molding material based on the measurement; deriving an equilibrium pressure based on the plurality of parameters obtained from a first slowest cooling rate among the plurality of cooling rates.

A measuring apparatus of bulk viscosity includes a temperature-controlling cylinder having a test chamber for holding a molding material and at least one piston configured to seal an opening of the temperature-controlling cylinder. The temperature-controlling cylinder and the at least one piston are configured for measuring pressures, specific volumes and temperatures (PVT) of the molding material by applying a plurality of cooling rates to the molding material inside the testing chamber under an isobaric environment, or applying a plurality of mechanical pressures to the molding material inside the testing chamber under an isothermal environment. The measuring apparatus further includes a process module configured for deriving a plurality of parameters in relation to the pressures, specific volumes and temperatures (PVT) of the molding material based on the measurement; deriving an equilibrium pressure based on the plurality of parameters obtained from a first slowest cooling rate among the plurality of cooling rates.

Systems and methods are provided for measuring the linear coefficient of thermal expansion or characterizing other physical properties of large-scale printed parts in various directions using digital image correlation techniques. Such system and methods can involve positioning a sample in a temperature-controllable chamber comprising a viewport in a bottom of the chamber, capturing a plurality of images of a bottom surface of the sample, and characterizing one or more physical property of the sample based on the plurality of images. As a result, a single camera is able to accurately capture the relevant strain measurements to determine the properties of the sample.

Systems and methods are provided for measuring the linear coefficient of thermal expansion or characterizing other physical properties of large-scale printed parts in various directions using digital image correlation techniques. Such system and methods can involve positioning a sample in a temperature-controllable chamber comprising a viewport in a bottom of the chamber, capturing a plurality of images of a bottom surface of the sample, and characterizing one or more physical property of the sample based on the plurality of images. As a result, a single camera is able to accurately capture the relevant strain measurements to determine the properties of the sample.

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.