Laser Applications

Contains research objectives and reports on five research projects.U. S. Air Force - Office of Scientific Research(Contract F44620-71-C-0051)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DAAB07-71-C-0300Naval Air Systems Comman

Quantum Electronics

Contains research objectives and summary of research for eight research projects split into three sections and a report on one research project.U. S. Air Force - Office of Scientific Research (Contract F44620-71-C-0051)Joint Services Electronics Program (Contract DAAB07-75-C-1346

Laser Applications

Contains research objectives and reports on three research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DAAB07-71-C-0300U. S. Air Force Office of Scientific Research (Contract F44620-71-C-0051)Naval Air Systems Comman

Quantum Electronics

Contains research objectives and summary of research on eight projects in three sections and reports on two research projects.U. S. Air Force - Office of Scientific Research (Contract F44620-71-C-0051)Joint Services Electronics Program (Contract DAAB07-74-C-0630)University of California, Livermore (Subcontract No. 7877409)U. S. Army Research Office - Durham (Contract DAHC04-72-C-0044

Quantum Electronics

Contains reports on three research projects.U. S. Air Force - Office of Scientific Research (Contract F44620-71-C-0051)Joint Services Electronics Program (Contract DAAB07-74-C-0630)University of California, Livermore (Subcontract 7877409

Quantum Electronics

Contains reports on three research projects.U. S. Air Force Office of Scientific Research (Contract F44620-71-C-0051)Joint Services Electronics Program (Contract DAAB07-71-C-0300)University of California, Livermore (Subcontract No. 7877409)U. S. Army Research Office - Durham (Contract DAHC04-72-C-0044

The effects of process variations on residual stress in laser peened 7049 T73 aluminum alloy

This paper reports measurements of the distribution of residual stress with depth from the surface in laser peened coupons made of a high-strength aluminum alloy. Residual stresses were measured using slitting (also known as the crack compliance method). Measurements were made on several coupons to: compare laser peening (LP) and shot peening (SP) residual stresses; ascertain the influence of LP parameters on residual stress; determine whether tensile residual stress existed outside the peened area; assess the variation of residual stress with in-plane position relative to the layout of the laser spots used for peening; and, determine the importance of a uniform spatial distribution of laser energy within the spot. Residual stress 0.1 mm from the surface due to LP and SP were comparable and the depth of the compressive stress for LP was far greater than for SP. Variations of most LP parameters did not significantly alter residual stress at shallow depths, but greater laser energy and larger layer overlap increased residual stress at depths between 0.2 and 0.6 mm from the surface. Residual stresses adjacent to the peened area were found to be compressive. Decreased levels of surface residual stress were found when laser spots had a non-uniform distribution of laser intensity. (C) 2002 Elsevier Science B.V. All rights reserved

The effects of process variations on residual stress in laser peened 7049 T73 aluminum alloy

This paper reports measurements of the distribution of residual stress with depth from the surface in laser peened coupons made of a high-strength aluminum alloy. Residual stresses were measured using slitting (also known as the crack compliance method). Measurements were made on several coupons to: compare laser peening (LP) and shot peening (SP) residual stresses; ascertain the influence of LP parameters on residual stress; determine whether tensile residual stress existed outside the peened area; assess the variation of residual stress with in-plane position relative to the layout of the laser spots used for peening; and, determine the importance of a uniform spatial distribution of laser energy within the spot. Residual stress 0.1 mm from the surface due to LP and SP were comparable and the depth of the compressive stress for LP was far greater than for SP. Variations of most LP parameters did not significantly alter residual stress at shallow depths, but greater laser energy and larger layer overlap increased residual stress at depths between 0.2 and 0.6 mm from the surface. Residual stresses adjacent to the peened area were found to be compressive. Decreased levels of surface residual stress were found when laser spots had a non-uniform distribution of laser intensity. (C) 2002 Elsevier Science B.V. All rights reserved