With the recent sale of a Laser Bond Inspection (LBI) system to Northrop Grumman Corporation (NGC), LSP Technologies has achieved another milestone in the commercial integration of LBI technology. Northrop Grumman’s implementation of LSPT’s proprietary LBI system marks another major airframe manufacturer to pursue implementing Laser Bond Inspection in their production process, further supporting Laser Bond Inspection as a reliable method for validating adhesively bonded structures.
LSP Technologies’ Laser Bond Inspection System
As the aviation industry increasingly works to make aircraft lighter, safer, and more fuel-efficient, aeronautical engineers are incorporating more composite elements such as carbon fiber into their vehicle designs. Composite airframe structures have the advantages of being lighter and more resistant to fatigue or corrosion damage than their metal counterparts. Composite panels are joined together using adhesive bonding agents, rather than traditional rivets or fasteners, which necessitates a new inspection process to interrogate the strength and safety of the composite bonds.
CompositesWorld: In January, David Lahrman, Vice President Business Development, highlighted Laser Bond Inspection at SME AeroDef in Long Beach, California. Sara Black of CompositesWorld blogged about her experience at SME AeroDef including meeting our very own David Lahrman to discuss the evolving technology of LBI. You can read the blog post here as it discusses the uses and technologies facing composites today.
She writes, “Still, if LBI could be combined with manufacturing and process controls for adhesive bonding such as those developed for the TRUST project…, we might get closer to bonded primary aerospace structure, without redundant fasteners.”
For more information about Laser Bond Inspection, click here.
LSP Technolgies is pioneering the field of using high energy lasers to non-destructively inspect adhesive bonds in composite and other bonded materials for weak or “kissing” bonds. The use of controlled, localized stress waves in materials and bonded joints offers new opportunities for the characterization of structures. Bonded joints in particular benefit from this application because there is no nondestructive inspection method to measure bond strength. LSP Technologies’ Laser Bond Inspection uses a high peak power short pulse laser to perform a localized proof test of a bond. The method can be nondestructively applied to strong bonds but will fail a weak bond, creating an internal disbond that is detectable by the laser bond inspection system itself or by post test ultrasonic inspection. To date numerous tests have shown the method to be sensitive to weak bonds in carbon fiber reinforced polymer composites structure bonds created by poor adhesive mixing, improper surface preparation or contamination. To Learn More click on the link. Flash http://mediazone.brighttalk.com/comm/ReedElsevier/33bdd84a70-22762-2251-24177 Windows Media http://mediazone.brighttalk.com/comm/ReedElsevier/b3a9cda1c2-22762-2250-24176
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.
Frequently Asked Questions About LBI
What is Laser Bond Inspection?
Laser Bond Inspection (LBI) is a new nondestructive evaluation (NDE) technology for testing the integrity of bonded materials and structures. The technology utilizes an advanced, high energy, pulsed laser system developed by LSP Technologies and specifically tailored for evaluating adhesively-bonded composite structures.
Why not use conventional NDE techniques such as ultrasonic inspection or radiography?
Conventional NDE techniques are useful when a gap, crack, or void is present in a bonded material. However, these techniques cannot identify problems, such as “kissing bonds” where the bonded materials are in contact but without structural strength. These problems can result from surface contamination, improperly mixed or outdated adhesives, or improper adhesive application techniques.
How does Laser Bond Inspection work?