Simplified elastic-plastic method

Elastic Stress Analysis - Simplified Elastic-Plastic Method. This method may be used in the case where the method indicated above shows the Pr + Pb + Q stress limits are not satisfied, but indicates that the Pl + Pb + Q range and excluding thermal effects must be less than Sps- Additionally, the effective alternating equivalent stress amplitude must include the fatigue penalty factor, ICej, which is based off of the simplified elastic-plastic criteria from the pre-2007 Section VIII, Division 2. Finally, a thermal stress ratcheting assessment must be made. 

Prediction of the restitution coefficient has been a challenging research topic for decades. Unfortunately, no reliable and accurate prediction method has been found so far. However, some useful simplified models with certain limits have been developed. One of them is the elastic-plastic impact model in which the compression process is assumed to be plastic with part of the kinetic energy stored for later elastic rebounding, with the rebound process considered to be completely elastic [Johnson, 1985]. In this model, it is postulated that (1) during the plastic compression process, a — r3/2a (2) during the compression process, the averaged contact pressure pm is constant and is equal to 3 Y and (3) the elastic rebound process starts when maximum deformation is reached. Therefore, the compressional force is... 

Houtman, J.L., Elastic-plastic strains from thermal shock at a discontinuity -a simplified approach. Simplified Methods in Pressure Vessel Amlysis, ASME Publication PVP-PB-029, Barsoum, R.S., Ed., pp. 1-12,1978. 

---