EFFECT OF RIPPLE LOAD ON THE STRESS-CORROSION CRACKING IN STRUCTURAL STEELS
The presence of small ripple loading can, under certain circumstances, significantly reduce time-to-failure and threshold stress intensity for stress-corrosion cracking (SCC) of steels. A predictive framework for such ripple-loading effects (RLE) is developed from concepts and descriptors used in SCC and corrosion fatigue characterisation. The proposed framework is capable of defining critical conditions required for the occurrence of RLE and predicting time-to-failure curves. The agreement between the predicted and laboratory data is excellent.
Effect of Loading Rate on Environmentally Controlled Cracking of Sensitized 304 Stainless Steel in High Purity Water
Abstract The environmentally-controlled crack propagation rates in the sensitized 304 stainless steel/water system at 95 C have been measured under static, monotonic; and cyclic stress conditions. It has been observed that the crack propagation rates increase with stress intensity rate and that the behavior under classical “stress corrosion” and “corrosion fatigue” conditions are quantitatively interrelatable. Of design importance, it is demonstrated that rapid loading times or even relatively small vibrations on a high mean load, are deleterious, even when the maximum stress intensity (KMAX) is below the threshold stress intensity (KISCC) measured under static loading conditions.
Economics of General-Purpose Assembly Robots
Summary A study of the comparative economics of various automatic assembly systems using general-purpose assembly robots is described. In the study, use is made of a “typical” candidate assembly whose profile is obtained from statistical analysis of actual products submitted by interested companies. It is shown that the choice of assembly system and the various parts presentation methods depends on three main factors, namely: the annual production volume per shift, the number of parts in the product and the equipment payback period.