Mr. David Lahrman will present a paper he co-authored entitled, “The LaserPeen™ Process and Emerging Applications”  September 12-15, 2011 at the 11th International Conference on Shot Peening.
ABSTRACT

“Laser peening has been demonstrated as a unique and valuable method to increase the resistance of aircraft gas turbine engine compressor and fan blades to foreign object damage (FOD) and improve high cycle fatigue (HCF) life.  Laser peening is also known as the LaserPeen^™ Process or laser shock processing (LSP).

 Laser peening drives a high amplitude shock wave into a material surface using a high-energy laser pulse.  The plastic deformation caused by the shock wave results in deep compressive residual stresses in the surface of the part.  The depth and magnitude of the residual stresses depend upon the material and the processing parameters.  Compressive residual stresses typically extend as deep as 0.040-0.060 inches (1.0 to 1.5 mm) below the surface and can approach the yield strength of the material.  These compressive residual stresses increase the resistance of materials to surface-related failures such as fatigue, fretting fatigue, and stress corrosion cracking.

 The successful use of laser peening on aircraft turbine engines blades is driving development efforts to expand the use of this technology to airframe structures, automotive gears, medical devices, nuclear systems, and general industrial applications.  The laser peening process is described and factors important for successful applications are discussed.”

Two additional papers are planned to be presented.  One by Yunfeng Cao and Yung C. Shin of the Center for Laser-based Manufacturing at Purdue University entitled, “Predictive self-closed modeling of laser shock peening and parametric study,” another by Anoop Vasu1 and Ramana V. Grandhi2 of the Department of Mechanical and Materials Engineering at Wright State University entitled, “Compressive Residual Stress Optimization in Laser Peening of a Curved Geometry.”  Follow the links below to read the abstracts for these two papers.

Predictive self-closed modeling of laser shock peening

Compressive Residual Stress Optimization in Laser Peening of

Dr. Jeff Dulaney and Dr. Allen Clauer of LSP Technologies will attend the 3rd International Conference on Laser Peening & Related Phenomena on October 11-14, 2011 in Grand Cube Osaka, Japan.  Dr. Dulaney has joined the conference committee. 

Dr. Dulaney will present on the topic Future Shock: Accelerating Technology, here is the abstract for his presentation. 

It takes an enormous effort to take technology from a laboratory research environment to commercial use.  Laser Shock Processing (LSP) of the 1970s evolved into the commercial success known today as laser peening.  There are several variants of laser peening in use today, and others yet to be discovered, developed, and integrated into commercial use.  The study of the laser-generated shock waves, so critical to laser peening, will find commercial applicability beyond imparting compressive residual stress in metals.  Computer models, currently being used to support commercial applications development, will continue to improve and lead the way to new applications and uses.  Overlay materials will evolve to enhance the effectiveness of laser peening through the use of special materials and techniques.  In situ process controls and diagnostics will continue to be developed to provide real-time feedback for process control and continuous quality assurance as critical parts are being processed.  Advancement of laser peening systems will enable new and unexpected applications. 

Dr. Clauer will present a paper he co-authored with Peter Gaydos entitled, “The Effect of Surface Treatments on Fatigue of Carburized X2M Steel.”   Here is the abstract for his paper.

“Carburized X2M specimens were tested in 3-point bending fatigue after having their surface treated with four different treatments both individually and in combination. The bend specimens were 102 mm x 34 x 8.5 mm, with the longitudinal edges of the tensile surface tapered. The surface treatments were Isotropic Surface Finishing (ISF), Low Stress Grinding (LSG), Shot Peening (SP) and Laser Shock Peening (LSP). The first three were also applied in combination with a follow-up LSP treatment, and also a combined ISF/SP/LSP treatment.
The results show that the fatigue strength increased with the type of surface treatment in the order of ISF, LSG, SP, LSP. The combination treatments produced fatigue strength equivalent to or slightly better than the LSP treatment alone.

These results will be discussed in the context of residual stress profiles and scanning electron microscopy of the surfaces and fracture surfaces. The observed modifications of the surfaces and compressive residual stresses lead to observable changes in crack initiation behavior.”

Other committee members from Ohio include:

Ramana V. Grandhi: Wright State University, USA

Kristina Langer: Wright-Patterson AFB, USA

S. R. Mannava: University of Cincinnati, USA

Visit the conference website to learn more

http://www.mapse.eng.osaka-u.ac.jp/3rdLP/

Residual stress profiles generated in AISI 8620 steel automotive ring gears showing the depth of beneficial compressive residual surface stress for LaserPeen® processing.

Effect of LaserPeen® Processing on Residual Stress and Fatigue Properties

Representative residual stress profile for Ti-6Al-4V showing the depth of beneficial compressive residual surface stress for LaserPeen® processing.