Abstract: A testing system for causing a physical change in a crack tip region of a crack within a specimen. The testing system includes a load application system for applying a load to the specimen having the crack formed therein, an electrothermal system for applying an electrical current through the specimen and comprising a power supply and a controller operably coupled to the load application system and the electrothermal system. The load application system configured to perform a crack growth test on the specimen. A method of thermally influencing a crack tip region of a crack within a specimen includes applying at least one pulse of current to the specimen to generate flux tangentially around the crack within the specimen and at the crack tip region and causing the crack tip region of the crack within the specimen to reach a predetermined activation temperature.

Abstract: A testing system for causing a physical change in a crack tip region of a crack within a specimen. The testing system includes a load application system for applying a load to the specimen having the crack formed therein, an electrothermal system for applying an electrical current through the specimen and comprising a power supply and a controller operably coupled to the load application system and the electrothermal system. The load application system configured to perform a crack growth test on the specimen. A method of thermally influencing a crack tip region of a crack within a specimen includes applying at least one pulse of current to the specimen to generate flux tangentially around the crack within the specimen and at the crack tip region and causing the crack tip region of the crack within the specimen to reach a predetermined activation temperature.

Abstract: The invention pertains to a test apparatus and method for assessing thermo-mechanical fatigue related phenomena within a test material wherein a heat source, such as a laser beam is applied to a specimen consisting of a body of the test material, thereby introducing heat to a primary heat introduction zone on the surface of the body to cause local cyclic heating. As part of the cycle, heat is removed through a portion of the specimen surface sufficiently remote from the heat introduction zone to create a substantially spherical temperature gradient within the specimen resembling that of a point source on a semi-infinite body. A stress gradient results from local thermal expansion, thus thermo-mechanically cycling the material. As a result of the thermo-mechanical cycling, phenomena including thermo-mechanically induced creep, residual stress, changes in physical properties, crack initiation and crack growth may be observed within the material, and evaluated for scientific or engineering purposes.

Abstract: The invention pertains to apparatus and method for precision thermal processing of a body. An energy beam emanating from an energy beam source is scanned across the surface of the body, creating heat input through a moving spot on the surface of said body. By means described herein to condition the spot shape and flux profile, the flux profile within the spot is configured to approximate a thermal solution obtained by solving a boundary condition of the third kind imposed upon the moving spot associated with the beam as it is scanned across the body. In this manner a predetermined surface temperature profile is imposed on the surface of the body within a moving, locally heated spot of predetermined shape and size.

Abstract: The invention pertains to an apparatus and method for controlled laser heating of a body. An optical integrating chamber, with an opening adjacent to the surface of the body, has a first and second aperture. A laser source, produces a beam of known power which is directed through the first aperture and the chamber opening onto the surface. A portion of the power of the laser beam is absorbed by the body, thereby heating it locally, and the remaining portion is substantially reflected back into the chamber. A photodetector samples the reflected light accumulated within the chamber through the second aperture, thereby discerning the total power of the reflected light, and enabling the computation of the absorbed power imparted as heat to the body. This computation is performed by a computer or controller, which also serves as a control feedback mechanism, by which the application of the laser is controlled based on the absorbed power imparted to the body during the heating process.

Abstract: The invention pertains to a test apparatus and method for assessing thermo-mechanical fatigue related phenomena within a test material wherein a heat source, such as a laser beam is applied to a specimen consisting of a body of the test material, thereby introducing heat to a primary heat introduction zone on the surface of the body to cause local cyclic heating. As part of the cycle, heat is removed through a portion of the specimen surface sufficiently remote from the heat introduction zone to create a substantially spherical temperature gradient within the specimen resembling that of a point source on a semi-infinite body. A stress gradient results from local thermal expansion, thus thermo-mechanically cycling the material. As a result of the thermo-mechanical cycling, phenomena including thermo-mechanically induced creep, residual stress, changes in physical properties, crack initiation and crack growth may be observed within the material, and evaluated for scientific or engineering purposes.

Abstract: A sample for fatigue and/or crack growth testing, including an axisymmetric or cylindrical gage section with a concentric hole running from a first end, and terminating within the gage section, with one mode of loading introduced at the terminus of the hole, and reacted at the end where the hole originates. A second mode of loading is optionally introduced at a second end of the specimen. Use of the specimen is described in both in the context of an apparatus for fatigue/crack growth testing described in the referenced parent application, as well as with conventional test machines.

Abstract: An apparatus for fatigue and/or crack growth testing, including a cyclic loading device and a preferred sample mounted at one end. An embodiment of the device has at least two concentric and coaxial load frames, with guiding interfaces between adjacent load frames to maintain alignment. Solid state actuation systems, which deform in response to the application of energy, are mounted at the end opposite the sample between adjacent load frames to provide up to two modes of actuation, including tension, compression, or torsion. The preferred sample includes a cylindrical gage section with a concentric hole running from a first end, and terminating within the gage section, with one mode of loading introduced at the terminus of the hole, and reacted at the end where the hole originates. A second mode of loading is optionally introduced at a second end of the specimen. Mount hardware for conventional specimens is also presented.

Abstract: A sample for fatigue and/or crack growth testing, including an axisymmetric or cylindrical gage section with a concentric hole running from a first end, and terminating within the gage section, with one mode of loading introduced at the terminus of the hole, and reacted at the end where the hole originates. A second mode of loading is optionally introduced at a second end of the specimen. Use of the specimen is described in both in the context of an apparatus for fatigue/crack growth testing described in the referenced parent application, as well as with conventional test machines.

Abstract: An apparatus for fatigue and/or crack growth testing, including a cyclic loading device and a preferred sample mounted at one end. An embodiment of the device has at least two concentric and coaxial load frames, with guiding interfaces between adjacent load frames to maintain alignment. Solid state actuation systems, which deform in response to the application of energy, are mounted at the end opposite the sample between adjacent load frames to provide up to two modes of actuation, including tension, compression, or torsion. The preferred sample includes a cylindrical gage section with a concentric hole running from a first end, and terminating within the gage section, with one mode of loading introduced at the terminus of the hole, and reacted at the end where the hole originates. A second mode of loading is optionally introduced at a second end of the specimen. Mount hardware for conventional specimens is also presented.