A unit for experimentally determining the life of cylindrical samples under the combined action of cyclic normal stresses and constant or variable tangential stresses under conditions of increased temperatures

1975 ◽  
Vol 7 (5) ◽  
pp. 642-644
Author(s):  
Z. B. Sankev ◽  
Ts. T. Dzhonov
Keyword(s):  
Normal Stresses ◽  
Tangential Stresses ◽  
Combined Action ◽  
Cylindrical Samples

scholarly journals Evaluation of bond between reinforcement and concrete

2018 ◽  
Vol 230 ◽  
pp. 02027 ◽  
Author(s):  
Olena Romashko ◽  
Vasyl Romashko
Keyword(s):  
Bond Strength ◽  
Stressed State ◽  
Statistical Evaluation ◽  
Contact Layer ◽  
Normal Stresses ◽  
Tangential Stresses ◽  
Universal Dependence ◽  
State Changes ◽  
Experimental Values ◽  
Concrete Elements

The scheme of stressed state changes of the concrete contact layer and reinforcing rod during its pulling out of concrete is considered. The most important drawbacks of the known methods for evaluating the bond strength of reinforcement to concrete have been analyzed. Particular attention is focused on bond estimating by average tangential stresses. It is substantiated why the linear dependence of these stresses on normal stresses in the reinforcement cannot cover the processes of reinforcement bonding with concrete in the stage of use of reinforced concrete elements. A universal dependence of the average tangential stresses for estimating the reinforcement bond to concrete at any stage of elements deformation is proposed. Statistical evaluation of the obtained dependence was made on the basis of theoretical and experimental values of the average tangential bonding stresses comparison. The area of use of reinforcement bond with concrete average stresses dependence is defined.

scholarly journals RESEARCH DEVELOPMENT OF CONTACT DEFORMATION STRESSES WHILE ROLLING

2020 ◽  
pp. 103-110
Author(s):  
Vasyl Muzychuk ◽  
Oleksii Tokarchuk
Keyword(s):  
Contact Area ◽  
Transverse Direction ◽  
Contact Stresses ◽  
Normal Stresses ◽  
Geometric Shapes ◽  
Tangential Stresses ◽  
Method Of Determination ◽  
Deformation Force ◽  
Over Time

The method of determination of contact normal and tangential stresses during rolling is considered, taking into account the development of deformation over time. There are many methods for determining the contact normal and tangential stresses, but they all consider the distribution along the strain boundary. This approach to solving problems does not allow to take into account the uneven deformation in the transverse direction and the influence of lateral non-contact zones adjacent to the actual deformation center. These factors should be taken into account when determining the tangent and normal stresses when rolling in calibers with different ratios of geometric shapes and rolling billet. Also, existing methods of determining contact normal and tangential stresses do not take into account the development of deformation over time. Deriving the equations that determine the deformation force of the friction force and pressure, it was assumed that the normal to the plane would not coincide with any of the axes of the coordinate system, and the inclined platform was considered as an inclined section in the parallelepiped voltage across the edges of the volume, which is distributed uniformly. The obtained formulas for determining the normal and tangent contact stresses in the deformation zone take into account rolling in calibers with different ratio of geometric shapes and rolling billet, characterize the dynamics of change of the deformation cell in time. The paper deals with rolling of AK6 alloy workpieces having Ø25x150 mm dimensions in oval caliber, with a height of 13 mm and a width of 29 mm and calculated normal and contact stresses. The plots of normal and tangent stresses show a change in the value of stress with increasing contact area and deformation time. The results of studies of normal and tangent stresses show a change in their values with increasing contact area and deformation time. When checking the proposed method, the discrepancy between the results of the theoretical calculation and the experimental data is not more than 4%, which confirms the possibility of using the method to determine the contact normal and tangential stresses during rolling.

A method of testing the strength of adhesive joints under the combined action of normal and tangential stresses

1989 ◽  
Vol 21 (4) ◽  
pp. 557-559
Author(s):  
S. V. Builov ◽  
E. A. Vlasenko ◽  
S. V. Dyatchenko ◽  
A. F. Shabanov
Keyword(s):  
Adhesive Joints ◽  
Tangential Stresses ◽  
Combined Action ◽  
Strength Of Adhesive Joints

An Analysis on Sliding of Biped Robots

2010 ◽  
Author(s):  
C. H. Liu ◽  
Chi-Hwa Wu ◽  
Yin-Tien Wang
Keyword(s):  
Stress Distribution ◽  
Point Contact ◽  
Ground Reaction Forces ◽  
Line Contact ◽  
Normal Stresses ◽  
Biped Robots ◽  
Tangential Stresses ◽  
Reaction Forces ◽  
Instantaneous Center ◽  
Contact Stress Distribution

In this paper we study the instability of biped robots that is a combination of both sliding and tipping over. Specifically, when robot falling occurs, the ground reaction forces and moments on a foot may determine if sliding also happens. We deal with the situation that tipping over is impending, and treat the following three possible types of contact stress distribution on the foot: point contact, line contact, and area contact. In line and area contact regions we assume that normal stresses are Hertzian, then tangential stresses may be determined by utilizing theory of instantaneous center of zero velocity in planar kinematics. From these normal and tangential stresses we may determine force combinations that cause sliding.

The Effect of Stress and Warfarin on the Adrenal Gland in Relation to Spontaneous Hemorrhage, as Judged by Measurement of Adrenal Ascorbic Acid and Serum Corticosterone

1971 ◽  
Vol 26 (02) ◽  
pp. 275-288 ◽  
Author(s):  
S Chattopadhyay ◽  
D. D Johnson ◽  
G. J Millar ◽  
L. B Jaques
Keyword(s):  
Ascorbic Acid ◽  
Acid Concentration ◽  
Ascorbic Acid Concentration ◽  
Corticosterone Concentration ◽  
Serum Corticosterone ◽  
Spontaneous Hemorrhage ◽  
Combined Action ◽  
Series Of Experiments ◽  
Pituitary Adrenal Axis

SummaryRats were subjected to the following procedures: No treatment, Stressor (10% NaCl i.p.), Warfarin for 7 days, Stressor followed by Warfarin; and groups were sacrificed at intervals for assessment of spontaneous hemorrhage and of adrenal ascorbic acid concentration. There was no hemorrhage in the no treatment and stressor groups; some hemorrhage in the warfarin group; profound hemorrhage with Warfarin + Stressor. The adrenal ascorbic acid concentration was found to be lower, 8 h and again 5 days after stress, and remained lower in the warfarin + stress animals. Warfarin had no effect on adrenal ascorbic acid level.In another series of experiments in which the stress consisted of an electric current to the cage floor for 6 sec over 15 min, rats were sacrificed daily for determination of serum corticosterone concentration and occurrence of spontaneous hemorrhage. There was a statistically significant increase of serum corticosterone concentration with stress, warfarin and combined warfarin and stress treatments (P< 0.001 for all three variables). There was a significant correlation (r = 0.96 and 0.89, P< 0.01) for serum corticosterone concentration with hemorrhage score and incidence of hemorrhage in stressed rats receiving warfarin, but not in those receiving only warfarin. The results indicate an activation, rather than an exhaustion, of the pituitary-adrenal axis during the combined action of anticoagulant and stress, which results in the development of spontaneous hemorrhage.

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