Constitutive Equation for Stainless Steel Used in Structural Engineering
Stainless steel is characterized by nonlinear stress-strain behavior, material anisotropy and different mechanical properties in tension and compression. As a result, it is necessary to define stress-strain relations of stainless steel precisely for the researches of mechanical behavior and stability of stainless steel member. This paper reviews the researches in constitutive relations models home and abroad, after introducing, analyzing, comparing the exist models, presents the three-stage stress-strain model proposed by Quach, which is defined using the three basic Ramberg-Osgood parameters and could be used in structural design by the current codes, considering the Quach equation as the most accurate constitutive equation for stainless steel material.
Experiments on stainless steel hollow sections—Part 1: Material and cross-sectional behaviour
Abstract Basic material properties and cross-sectional data (stress–strain curves and load–end shortening curves) are presented for square, rectangular and circular hollow section specimens in Grade 1.4301 stainless steel. The material tests cover flat material in tension and in compression as well as corner material in tension. Modifications to the Ramberg–Osgood representation are suggested to ensure a close fit to both tensile and compressive behaviour over the full range of strains of interest. Results, including full load–end shortening curves, for a total of 37 stub column tests have been presented. The results have been used to develop an explicit relationship between cross-sectional slenderness and cross-sectional deformation capacity, which forms the basis for a proposed new design approach for stainless steel structures.
Mechanism of the depressor response to dopamine in the rat treated with phenoxybenzamine.
Alterations of hypotensive responses to dopamine by antagonists were characterized in alpha-blocked, anaesthetized rats. Responses were not affected by d-propranolol (0.1 mg/kg) whereas d,1-propranolol (0.1 mg/kg) or haloperidol (1.0 mg/kg) attenuated them; higher doses of inhibitors (1.0 mg/kg; 5.0 mg/kg, respectively) failed to produce a higher inhibition, but combinations of low doses abolished the depressor responses. In adrenalectomized rats, hypotensive responses decreased; haloperidol always attenuated the responses while d,1-propranolol became ineffective. Dopamine produced an enhancement of plasma adrenaline and noradrenaline levels, which was decreased by d,1-propranolol and increased by haloperidol. The data suggest that in rats the depressor component of dopamine is due to activation of both dopaminergic and beta-adrenoceptors. The beta component appears to be due to the release of adrenaline. The results also support the concept of the existence in sympathetic nerve endings and adrenal glands of stimulatory beta-adrenergic and inhibitory dopaminergic prejunctional receptors.