Abstract: A system for evaluating the integrity of a bonded joint in an article includes a laser configured in a laser shock processing arrangement to perform a laser shock processing treatment on the article. A beam delivery system employs an articulated arm assembly to communicate the radiant energy emitted by the laser to a process head proximate the article. The laser shock processing treatment causes the formation of shockwaves that propagate through the article, inducing internal stress wave activity that characteristically interacts with the bonded joint. A sensor detects a stress wave signature emanating from the article, which is indicative of the integrity of the bond. A detector such as a non-contact electromagnetic acoustic transducer provides a measure of the stress wave signature in the form of surface motion measurements.

Abstract: A system for neutralizing a buried mine includes a laser that is configured to generate laser energy that communicates through the covering ground material and accesses the mine in a manner sufficient to neutralize the mine. Neutralization can occur by deflagration or detonation. The laser includes a solid-state lasing medium that is run substantially uncooled during the lasing run. Namely, the lasing medium is operated without cooling until the lasing medium reaches a temperature where thermal population in a lower laser level begins to significantly lower inversion density. Following completion of the lasing run, the lasing medium is cooled at a rate limited only by a thermal stress fracture level of the lasing medium. Operation of the laser in this manner permits the laser to deliver high-irradiance, high-repetition rate pulses according to a burst mode operation that successfully accomplishes neutralization in a desired time period.

Abstract: Methods, systems, and apparatuses are provided for generation of focused stress waves that selectively apply tensile stress to local regions of a bonded article.

Abstract: Methods, systems, and apparatuses are provided for generation of focused stress waves that selectively apply tensile stress to local regions of a bonded article.

Abstract: A diagnostic means to enable real-time inspection of bonded structures. The disclosed apparatus detects bond failure stress waves on-axis from the front side (beam application side). Pi-box and pi-rail EMAT gauges can be used with the disclosed apparatus. An inductively coupled EMAT may also be employed. An improved means to remotely deliver an interrogating laser beam to a surface is provided. The process head may utilize a water column or a water film. The water film process head may include the use of either a single water film or two spaced apart water films. The disclosed apparatus can be used with bonded composite structures, bonded structures using various materials, and to determine the dynamic strength of unbonded solid materials. The apparatus may also be used in other applications that require remote flexible delivery of a localized stress wave to a material and/or diagnosis of the resultant stress waves.

Abstract: A system for neutralizing a buried mine includes a laser that is configured to generate laser energy that communicates through the covering ground material and accesses the mine in a manner sufficient to neutralize the mine. Neutralization can occur by deflagration or detonation. The laser includes a solid-state lasing medium that is run substantially uncooled during the lasing run. Namely, the lasing medium is operated without cooling until the lasing medium reaches a temperature where thermal population in a lower laser level begins to significantly lower inversion density. Following completion of the lasing run, the lasing medium is cooled at a rate limited only by a thermal stress fracture level of the lasing medium. Operation of the laser in this manner permits the laser to deliver high-irradiance, high-repetition rate pulses according to a burst mode operation that successfully accomplishes neutralization in a desired time period.

Abstract: A laser processing method for processing a hidden surface of a workpiece, the hidden surface being disposed within a recess having an opening. The method includes inserting a reflective member into the recess and directing a pulse of coherent energy to reflect off of said reflective member and impact the hidden surface of a workpiece to create a shock wave. Alteratively a surface of the recess may be modified to laser shock process the hidden surface. In one particular embodiment, the reflective member is specifically shaped toprovide diction of a pulse of coherent energy to a hidden surface so that a substantially uniform energy density is applied to the hidden surface. In an additional embodiment, the method is optimized for preventing damage to the reflective member. In one particular embodiment, the reflective member is composed of a fluid.

Abstract: A method and apparatus for quality control of laser shock processing. The method includes measuring emissions and characteristics of a workpiece when subjected to a pulse of coherent energy from a laser. These empirically measured emissions and characteristics of the workpiece are correlated to theoretical shock pressure, residual stress profile, or fatigue life of the workpiece. The apparatus may include a radiometer or acoustic detection device for measuring these characteristics.

Abstract: An apparatus for measuring the strength of a pressure pulse created from a laser peening device. The apparatus is reusable, and includes a pressure-sensitive medium, a back-up disk, and a cap, all disposed within a housing having a removable lid. All components of the apparatus are replaceable, thereby allowing an operator to utilize the apparatus more than once despite the harsh environment of laser peening.

Abstract: An apparatus for measuring the strength of a pressure pulse created from a laser peening device. The apparatus is reusable, and includes a pressure-sensitive medium, a back-up disk, and a cap, all disposed within a housing having a removable lid. All components of the apparatus are replaceable, thereby allowing an operator to utilize the apparatus more than once despite the harsh environment of laser peening.

Abstract: A monitor of a plurality of optical signals utilizing fiber optics which form an array. An image of the array is captured and the captured image is processed for detecting a quality of an optical signal such as the presence, absence, intensity, wavelength, or other quality of the optical signal. A method of monitoring a plurality of optical signals by capturing a plurality of optical signals from an array of signals and detecting a quality of at least one optical signal is also disclosed.

Abstract: A method and apparatus for quality control of laser shock processing. The method includes measuring emissions and characteristics of a workpiece when subjected to a pulse of coherent energy from a laser. These empirically measured emissions and characteristics of the workpiece are correlated to theoretical shock pressure, residual stress profile, or fatigue life of the workpiece. The apparatus may include a radiometer or acoustic detection device for measuring these characteristics.

Abstract: An apparatus for measuring the strength of a pressure pulse created from a laser peening device. The apparatus is reusable, and includes a pressure-sensitive medium, a back-up disk, and a cap, all disposed within a housing having a removable lid. All components of the apparatus are replaceable, thereby allowing an operator to utilize the apparatus more than once despite the harsh environment of laser peening.

Abstract: A method and apparatus for quality control of laser shock processing. The method includes measuring emissions and characteristics of a workpiece when subjected to a pulse of coherent energy from a laser. These empirically measured emissions and characteristics of the workpiece are correlated to theoretical shock pressure, residual stress profile, or fatigue life of the workpiece. The apparatus may include a radiometer or acoustic detection device for measuring these characteristics.

Abstract: The invention includes a laser processing method for processing a hidden surface of a workpiece, the hidden surface disposed within a recess having an opening. The method comprises inserting a reflective member into the recess and directing a pulse of coherent energy to reflect off of said reflective member and impact the hidden surface of workpiece to create a shock wave. Alteratively a surface of the recess may be modified to laser shock process the hidden surface.

Abstract: Methods and apparatus for improving properties of a solid material in a target (11) by providing shock waves therein. There are directed to the surface of the material (11) pulses of coherent radiation (12) having average energy fluence of at least about 10 Joules per square centimeter and rise time of not longer than about 5 nanoseconds within a fluorescence envelope lasting about 0.5 to 5 milliseconds, at a rate of about 1 radiation pulse per 100 to 200 microseconds.The leading edge of each pulse (12) is sharpened by providing in its path an aluminum film (18) about 150 to 5000 angstroms thick that is vaporized by the pulse and then is moved across the path so that a later pulse (12) strikes an area of the film (18) not already vaporized by an earlier pulse (12).The radiation (12) is amplified by an amplifier (23) comprising a rod of phosphate laser glass that was strengthened by an ion exchange process.

Abstract: An improved method and an apparatus for altering properties in a solid target by using the radiation emitted by a high power pulsed laser to generate a short duration, high amplitude pressure pulse is directed at the front side of solid target to alter material properties. The front side of the solid target is covered with an overlay material that is transparent to laser light, and the back side is placed in direct contact with a trapping material having substantially the same acoustical impedance as the metal substrate. When the solid target is processed by the pulsed laser, the microstructure and the stress state of the target are altered in a predictable manner.

Abstract: A method for imparting increased mechanical strength to a glass object having imperfections in a surface thereof. The glass object is heated to a temperature above the strain point of the glass. A laser beam is generated having a wavelength absorbable by the glass and impinged on all portions of the surface containing the imperfections. The power density at which the beam is impinged is sufficient to rapidly heat a surface stratum of the glass to establish a thermal gradient therein whereby the viscosity at a depth from the surface sufficient to encompass the imperfections is low enough that the stress induced by the surface tension of the glass at the sites of the imperfections is sufficient to cause flow of glass and effect a reforming of the glass surface at said sites.