On Collapse Pressure for Pressure Vessel Components of Strain Hardening Materials. 1st Report. Mechanical Definition on Plastic Collapse for Tori-Spherical Head under Internal Pressure.

Abstract

Elastic-Plastic analyses for tori-spherical head of strain hardening material, which is a typical gross structural discontinuity of pressure vessels, are carried out in the practially wide geometrical range of the component. Plastic behaviors, such as yield zone, deformation, stress and strain in plastic range are investigated in detail. As a result, plastic collapse point is mechanically defined as the turning point of the plastic strain increment ratio at the maximum stress point of the component, which is qualitatively characterized as the starting point to excessive plastic deformation.