LSP Conference 2010

LSP Technologies, Inc. will be presenting at the 2nd International Conference on Laser Peening. Three of our executives will be presenting, as listed below.

 

The conference is specifically designed to bring together the most relevant scientists/specialists from all over the world. This conference will enable them to exchange their knowledge and to discuss and cooperate on recent state-of-the-art innovative technologies related to Laser Peening/Laser Shock Processing, along with the latest developments and implementations in the industrial applications of laser peening. The scope of the conference will be dedicated not only to the academic or industrial community working on laser-peening systems or applications, but also to all those working on surface modification technologies or structural integrity interested by the emergence of this process.

Monday, April 19, 9:40 AM
“Advances in Modeling of Laser Peening for Carburized Steels”
Mr. Richard D. Tenaglia

Laser peening is being evaluated by the U.S. Army to toughen helicopter gears, transmission components, and other rotorcraft structural parts.  A critical need exists to boost engine power, particularly when operating in high altitude environments.  Laser peening offers the potential to increase the fatigue performance or damage tolerance of these components without increasing the size or the weight of the propulsion system.

Computer simulation is essential for reducing the development time and costs for optimizing the use of laser peening of actual components.  Modeling of advanced carburized gear steels presents unique challenges.  The composition and hardness gradients in the surface of the carburized steel parts cause gradients of mechanical and physical properties, which affect the laser peen processing response.  To simulate the response properly, it is important to carry the residual stress state from heat treatment forward into the laser shock peening models to predict the resulting compressive residual surface stress profiles, and then transition these profiles to the final part loading models for performance prediction.

This paper presents the recent results of modeling and experimental validation efforts to simulate laser peening of carburized steels, with a correlation of residual stress profiles to fatigue performance.

Monday, April 19, 2:10 PM
“Production Laser Peening Using Automated Overlay Applicators”
Dr. Jeff L. Dulaney

Over the past three years, LSP Technologies has developed an automated overlay applicator system suitable for production laser peening.  This automated system increases throughput and decreases production cost by eliminating manual operations typically associated with tape overlays.  The automated overlay applicators are interfaced with the laser and parts positioning equipment to create a smooth production operation.  The part moves into position, the liquid opaque overlay is applied, the transparent water overlay is applied, the laser fires, and a blast of air preps the surface for the next automated sequence.  The sequence is repeated at the repetition rate of the laser system until processing is completed.

This technology represents an important breakthrough in how laser peening will be implemented in the future: no more expensive, labor-intensive manual applications of tape or similar opaque overlays.  We have successfully introduced automated overlay applicator technology into our production operations, using it to process thousands of parts across two different market sectors: gas turbine engines and tooling dies.

In this presentation, the author will discuss the operation of the automated overlay applicator system, critical elements of its operation, and how it transitioned from development to production.  The presentation will include photographs of hardware and an operational video showing the system in action. 

Tuesday, April 20, 8:00 AM
“Fretting Fatigue of Laser Peened Ti-6A1-4V”
Dr. Allan H. Clauer

Fretting fatigue tests of laser peened Ti-6Al-4V were performed. The laser peening conditions included use of large, 5.6 mm diameter, and small, 1 mm diameter spots. Both produced significant increases in fatigue life. Depending on the fatigue loading conditions, fatigue life was increased from 10 to greater than 25 times, with most of the laser peened specimens running out at 106 cycles. Increasing the bulk fatigue loads to produce failures was limited by the capacity of the fatigue testing machinery.  The fretting fatigue cracks observed in the laser peened material, appear to be similar to those formed in non-laser peened Ti-6Al-4V, presumably because the contact stresses dominate the laser peening induced compressive residual stresses at the fretting surface. However, the laser peening compressive residual stress inhibited their evolution into propagating fatigue cracks. The small laser spot patterns produced a rough surface compared to the large spots, and showed a much different fretting behavior. However both spot sizes produced comparable fatigue life increases.  Metallographic examinations of the fretting surfaces and fretting cracks produced within the fatigue bars and the fretting pads by different fretting and laser peening conditions will be presented and discussed.

This investigation demonstrates that laser peening produces a significant life increase in Ti-6Al-4V under fretting fatigue conditions. It also shows that small spots can produce comparable life increases to large spots even though the fretting situation differs due to the rougher surface produced by the small spots.