Hydrostatic stress

About: Hydrostatic stress is a research topic. Over the lifetime, 1568 publications have been published within this topic receiving 37773 citations.

Hydrostatic Stress Effects in Metal Plasticity

Abstract: Since the 1940s, the theory of plasticity has assumed that hydrostatic stress does not affect the yield or postyield behavior of metals. This assumption is based on the early work of Bridgman. Bridgman found that hydrostatic pressure (compressive stress) does not affect yield behavior until a substantial amount of pressure (greater than 100 ksi) is present. The objective of this study was to determine the effect of hydrostatic tension on yield behavior. Two different specimen geometries were examined: an equal-arm bend specimen and a double edge notch specimen. The presence of a notch is sufficient to develop high enough hydrostatic tensile stresses to affect yield. The von Mises yield function, which does not have a hydrostatic component, and the Drucker-Prager yield function, which includes a hydrostatic component, were used in finite element analyses of the two specimen geometries. The analyses were compared to test data from IN 100 specimens. For both geometries, the analyses using the Drucker-Prager yield function more closely simulated the test data. The von Mises yield function lead to 5-10% overprediction of the force-displacement or force-strain response of the test specimens.

The Effect of Hydrostatic Pressure on Plastic Deformation and Creep of Polycrystalline Metals at Elevated Temperatures

Abstract: It has been the object of the present study to elucidate the effect of hydrostatic stress on the mechanical behavior of polycrystalline metals at elevated temperatures. In the studies hitherto made by authors, the effect of hydrostatic stress on metallic tensile creep and torsional creep was investigated through the tests under combined hydrostatic pressure at room temperature. The question concerning the pressure effect under the influence of elevated temperatures has, however, been left still for further inquiry. From (The present) analytical and experimental studies on tensile plastic deformation and tensile creep under hydrostatic pressure at elevated temperatures, the following conclusions have been made.(1) The effect of combined hydrostatic pressure on the plastic flow stress of polycrystalline metals at elevated temperature is observable in the region of large plastic deformation. Therefore, it is necessary to consider the influence of hydrostatic stress in the yielding condition at this region.(2) The effect of concentrated pressure on metallic creep results in decrease in the strain rate of second creep stage at elevated temperature as the same behavior at room temperature. The effect of hydrostatic pressure on metallic creep at elevated temperature may be more intensive than that on the static tensile strength at the same temperature.