Residual Stresses

Residual stresses are always introduced in materials when they are produced, or when they undergo non-uniform plastic deformation during use. The circumstances that can cause residual stresses are therefore numerous. Residual stresses exist in all materials and, depending on their distribution, can playa beneficial role (for example, compressive surface stress) or have a catastrophic effect, especially on fatigue behaviour and corrosion properties. The subject of residual stresses took form around 1970 with the development of methods to measure macroscopic deformations during the machining of materials or on an atomic scale by X-ray diffraction. These techniques have made considerable progress in the last 20 years. The meetings organized in several countries (Germany, France, Japan, etc. ) have largely contributed to this progress, aided by the numerous exchanges of information and knowledge to which they have given rise. Studies of the formation of residual stresses began more slowly, but have progressed with the emergence of increasingly realistic models of materials behaviour and with access to ever more powerful codes for numerical calculations. Two successive meetings for discussing this topic have been held in Europe. The first, held in 1982 in Nancy (France), consisted of 30 participants from 5 countries. The second was held in Linkoping (Sweden) in 1984, with 80 participants of 16 nationalities. It was decided to hold a first International Conference, ICRS, to address all aspects of the problem. Held in 1986 in Garmisch-Partenkirschen (FRG), it was an assembly of neady 300 participants from 21 countries.