Laser Peening and Bond Inspection at the ASME Turbo Expo 2012

LSP Technologies will be at the ASME
Turbo Expo 2012 – Presented by the International Gas Turbine Institute Ju
ne 11-15, 2012 at the Bella
Center in Copenhagen, Denmark.  Dr. Jeff Dulaney, founder, President and CEO of LSPT and David Lahrman, Director of
Business Development will both be at the convention and in our display booth.

Visit the ASME Turbo Expo 2012 web site for more information about the event… information from the web site…The International Gas Turbine Institute (IGTI) of ASME is
dedicated to supporting the international exchange and development of information
to improve the design, application, manufacture, operation and
maintenance, and environmental impact of all types of gas turbines,
turbomachinery and related equipment.Since 1956 IGTI has been an important resource for the gas turbine community,
hosting an annual conference and exposition, Turbo Expo, as well
as providing professional development tools to foster knowledge and
career growth. In addition, IGTI’s 18 technical committees provide
regular ongoing forums for program development and technical exchange,
addressing all areas of technical expertise related to gas turbines.

Wright Dialogue with Industry

July 20-21, 2011
Hope Hotel & Conference Center
Wright-Patterson Air Force Base, Dayton, Ohio

LSP Technologies is proud to attend again this year to discuss it’s laser peening process and services as well as it’s laser bond inspection process.

The following is taken from their website:
The Dayton Area Defense Contractors Association (DaytonDefense) will sponsor the fifth “Wright Dialogue with Industry” conference on July 20-21, 2011 at the Hope Hotel and Conference Center, Wright-Patterson AFB, OH.

The purpose of this conference is to help promote economic development activity among local defense contractors and Wright-Patterson Air Force Base. Please plan to attend this year’s Wright Dialogue with Industry to hear first-hand from key leaders of the Air Force Research Laboratory (AFRL) organization as they discuss both current and future business opportunities.  There will be opportunities throughout the day for more detailed breakout sessions where you can pose your particular questions to the Laboratory representatives. Throughout the course of the event, there will be time to network and discuss opportunities to do business in greater detail with AFRL.

Mobile Laser Bond Inspection System Demonstration

On November 10, 2009 LSP Technologies successfully demonstrated to the USAF the mobile laser bond inspection system that was constructed on two USAF SBIR (small business innovative research) programs.  This advanced pulsed laser inspection system is configured in a self-contained, environmentally-controlled enclosure that sits on a mobile platform.  This advancement is essential for rapid insertion of the LBI process into aircraft manufacturing plant operations and aircraft maintenance depots.  There exists no equivalent laser system in the commercial sector.

Laser Bond Inspection (LBI) is a local proof-testing method that applies a well-controlled dynamic stress to a composite structure, and senses the failure of weak laminate or weak adhesive bonds in response to the stress. The dynamic stress is generated by the interaction of a pulsed laser beam with a composite structure. The controlled stressing of the composite material has no effect on the material or bond if it is not damaged, defective, or substandard. The technique offers a practical structural health monitoring solution for locating composite damage and defect regions in laminate and laminate-adhesive bonds in aircraft.

Benefits of laser bond inspection include the following:

  • Allows the detection of “kissing bonds” in composite structures that are not detectable by standard nondestructive inspection techniques
  • Makes calibrated dynamic strength measurements to find weak areas in composite laminate or adhesive bonds that conventional testing cannot locate
  • LBI may be applied to metal-to-composite and metal-to-metal bonds as well as pure composite assemblies
  • LBI can be applied for inspecting a variety of commercial,  reconnaissance, and targeting aircraft
  • LBI improves reliability and reduce maintenance cost of composite aircraft structures

As program manager of the project, David W Sokol would like to thank Steve Toller, Jim Niehaus, Brad Lance, Rick Mills, and Kevin Romer for all their hard work on the program.  He would also like to thank David Lahrman for working with WPAFB staff in making this USAF SBIR program possible.

Laser Generation of 100-kbar Shock Waves in Solids

Originally published in Shock Compression of Condensed Matter 1991, S.C. Schmidt, R.D. Dick, J.W. Forbes, D.G. Tasker (editors) copyright 1992 Elsevier Science Publishers B.V.

Authored by Craig T. Walters

Neodymium-glass laser pulses (1.06-mm wavelength, 25-ns pulse width) have been used to generate shock waves with peak pressures in the 5- to 120-kbar range at the front surface of solids. Relatively uniform irradiance levels were employed with circular beam areas in the 0.4- to 1.5-cm2 range and single pulse energy up to 800 J (fluences ranged from 200-2000 J/cm2). At 1000 J/cm2, the resulting peak shock pressure is about 35 kbar. By confining the plasma with a transparent glass overlay, this peak pressure was raised to 120 kbar. The nature of the plasma initiation process has been revealed through careful simultaneous temporal resolution of the beam-power, temperature, and stress-wave details.

High-power laser pulses have been used to produce stress waves in materials for more than two decades. Most of the measurements of stress wave amplitude have been performed with pulse fluences less than 100 J/cm2. Laser exposures with fluences many orders of magnitude greater than this have been conducted, but pressures have not been directly measured in these cases. We report here measurements of stress-wave amplitudes in laser interactions with fluences in the range 200-2000 J/cm2 with and without plasma confinement (transparent overlays). A map of pressures that may be achieved with single laser pulse interactions is presented in Figure 1 in terms of peak power density. The dashed line at high intensity follows the set of ablation pressures estimated by Cottet et al.1,2 in the correlation of thin aluminum foil spallation data. These estimates follow a 0.7 power dependence on intensity. Similar estimates made by Eliezer et al.3 and Gilath et al.4 are shown in Figure 1 by the dotted line for aluminum and the chain dashed line for carbon/epoxy at lower intensity. The open circles are peak pressures measured recently with 20- to 30-ns pulses at Battelle 5,6 at the front surface of stress gage packages coated with either graphite or carbon/polymer (black paint). These data agree with the estimate of Reference 3 at low intensity, but rise nearly linearly up to 5 x 1010 W/cm2 in contrast to the model. The solid circles show the effect of confining the plasma at these intermediate intensities with a transparent overlay. These pressures were in the 90 to 120 kbar range and are believed to be the highest directly recorded pressures generated in laser interactions with solids. The solid squares and triangles present the measurements of confined interactions by Fairand and Clauer7 and by Ballard et al 8 for 30-ns pulses. These data are highly consistent up to about 3 x l09 W/cm2 (90 J/cm2). For fluences in the 100- to 1000-J/cm2 range, the detailed nature of the transparent overlay probably takes on increased importance as breakdown processes interfere with energy delivery to the absorbing interface. Our data indicate that some benefit in increased pressure from a correctly designed overlay may be possible at even higher fluences than those investigated, contrary to the plateau seen in the Ballard data. Careful examination of the pressure histories with different coatings and with and without overlays has also revealed some detail of the plasma initiation process as discussed below.

To download the entire article as a pdf: Laser Generation of 100-kbar Shock Waves in Solids