Reduction of metal consumption in engineering structures attainable by the energy-based method for strength analysis

Abstract

The main disadvantages of the traditional stress-based method for static strength analysis are shown which prevent effective usage of plastic, hardening and cold-resistant steels and alloys. The energy-based method for strength analysis whose keystone is the determination of allowable stresses offers the possibility of a differentiated increase in the level of those stresses for many structural materials owing to the analytically developed mechanism of quantitative consideration of the available plasticity, strain- and low-temperature hardening and fracture toughness (crack growth resistance) and transformation of those characteristics from qualitative to calculated ones. This is equivalent to an automatic correction of safety factors when instead of being the values strictly standardized, they become the values dependent on the main properties of specific materials. The development of the new energy-based method is a result of the evolution of the mechanics of a deformable solid which is implemented directly in the practice of strength analyses. Its application, instead of the stress-based method which is a particular case of the energy-based one, provides a complete consideration of actual strength reserves for different elastic, hardening and cold-resistant metallic materials and their reduced consumption under the principle “the higher the quality, the lower the consumption”. The validity of the energy-based method is supported by the test results for welded pressure vessels under static and cyclic loading by internal pressure at room and cryogenic temperatures.