Analytical and experimental investigations on internally ring stiffened steel tubular joints

1992 ◽  
Vol 14 (6) ◽  
pp. 417
Keyword(s):  
Experimental Investigations ◽  
Tubular Joints ◽  
Stiffened Steel

Structural Efficiency of Internally Ring‐Stiffened Steel Tubular Joints

1992 ◽  
Vol 118 (11) ◽  
pp. 3016-3035 ◽  
Author(s):  
D. S. Ramachandra Murthy ◽  
A. G. Madhava Rao ◽  
P. Gandhi ◽  
P. K. Pant
Keyword(s):  
Structural Efficiency ◽  
Tubular Joints ◽  
Stiffened Steel

Behavior of Unstiffened and Stiffened Steel Tubular T-Joints

1989 ◽  
Vol 111 (1) ◽  
pp. 56-60 ◽  
Author(s):  
G. Raghava ◽  
A. G. M. Rao ◽  
D. S. R. Murthy
Keyword(s):  
Stress Concentration ◽  
Stress Gradient ◽  
High Stress ◽  
Vital Role ◽  
Wave Forces ◽  
Tubular Joints ◽  
Abrupt Changes ◽  
Element Technique ◽  
Stiffened Steel ◽  
Very High

Offshore towers standing in deep sea are susceptible to cyclic nature of wave forces. Fatigue failure initiates at the welded tubular joints of these structures where a very high stress gradient and localized stress concentration exist due to abrupt changes in the geometry. Stress concentration plays a vital role in the design of steel tubular joints, as it directly affects the fatigue life of the structures. This paper presents results of an experimental study on the behavior of an unstiffened and a stiffened steel tubular welded T-joint under axial brace loading. The effect of internal ring stiffeners has been studied theoretically and experimentally. In the experimental technique, the specimens were extensively strain-gaged and the stress distribution determined under static load. The analytical results have been obtained by finite element technique.

Fatigue crack growth in stiffened steel tubular joints in seawater environment

2000 ◽  
Vol 22 (10) ◽  
pp. 1390-1401 ◽  
Author(s):  
P. Gandhi ◽  
D.S. Ramachandra Murthy ◽  
G. Raghava ◽  
A.G. Madhava Rao
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Tubular Joints ◽  
Seawater Environment ◽  
Stiffened Steel

Interactive Buckling Tests of Externally Pressurized Stiffened Bent Pipelines

2013 ◽  
Vol 553 ◽  
pp. 103-109
Author(s):  
V. Hoseinzadeh ◽  
H. Showkati
Keyword(s):  
Weld Line ◽  
Bending Moment ◽  
External Pressure ◽  
Mode Shapes ◽  
Experimental Investigations ◽  
Buckling Modes ◽  
Real Behavior ◽  
Pure Compression ◽  
Interactive Buckling ◽  
Stiffened Steel

The paper reports an experimental study on the collapse of long uniformly pressurized ring-stiffened bent pipelines. Bending in the presence of external pressure is experienced by pipelines during their installation and operation. The buckling aptitude of shells is dependent on two leading geometric ratios, i.e. the length to radius and radius to thickness. In this paper, four different ring-stiffened steel pipeline specimens were tested to collapse. The evolution of the specimens behavior that has been recorded in the presence of a uniform external pressure is outlined. A thin-walled pipeline is sensitive to buckling phenomena when it experiences locally a compressive stress. It is often considered that its behavior under bending is rather similar to pure compression, but very few are the experimental investigations that precise the real behavior of it. A comparison of experimental data to empirical formulae and design recommendations is finally achieved. Consequently, it has been found that with using ring stiffeners the structure behavior against the combination of loads is improved in all loading paths. Also it has been found that buckle propagation in all manners occurs suddenly and dynamically and the amount of initial bending moment is not serious in defining the number of buckling modes. Also, the considerable effects of a longitudinal spot weld line on the buckling strength and mode shapes are verified.

Experimental investigations of the use of cartilage in tympanic membrane reconstruction

2000 ◽  
Vol 21 (3) ◽  
pp. 322-328 ◽  
Author(s):  
T ZAHNERT ◽  
K HUTTENBRINK ◽  
D MURBE ◽  
M BORNITZ
Keyword(s):  
Tympanic Membrane ◽  
Experimental Investigations

EXPERIMENTAL INVESTIGATIONS OF THE QUANTUM PHOTOVOLTAIC EFFECT IN InAs-GaSb SEMICONDUCTOR SUPERLATTICES

1987 ◽  
Vol 48 (C5) ◽  
pp. C5-183-C5-186
Author(s):  
J. BLEUSE ◽  
P. VOISIN ◽  
M. VOOS ◽  
L. L. CHANG ◽  
L. ESAKI
Keyword(s):  
Photovoltaic Effect ◽  
Experimental Investigations ◽  
Semiconductor Superlattices

Evaluation of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings by the multi-frequency radio wave method of a slow surface electromagnetic waves

2020 ◽  
pp. 51-58
Author(s):  
Aleksandr I. Kazmin ◽  
Pavel A. Fedjunin
Keyword(s):  
Radio Wave ◽  
Noise Level ◽  
Electromagnetic Waves ◽  
Dielectric Materials ◽  
Geometric Parameters ◽  
Experimental Investigations ◽  
Wave Method ◽  
Dielectric Coatings ◽  
Surface Electromagnetic Waves ◽  
Multilayer Dielectric

One of the most important diagnostic problems multilayer dielectric materials and coatings is the development of methods for quantitative interpretation of the checkout results their electrophysical and geometric parameters. The results of a study of the potential informativeness of the multi-frequency radio wave method of surface electromagnetic waves during reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings are presented. The simulation model is presented that makes it possible to evaluate of the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric coatings. The model takes into account the values of the electrophysical and geometric parameters of the coating, the noise level in the measurement data and the measurement bandwidth. The results of simulation and experimental investigations of reconstruction of the structure of relative permittivitties and thicknesses of single-layer and double-layer dielectric coatings with different thicknesses, with different values of the standard deviation (RMS) of the noise level in the measured attenuation coefficients of the surface slow electromagnetic wave are presented. Coatings based on the following materials were investigated: polymethyl methacrylate, F-4D PTFE, RO3010. The accuracy of reconstruction of the electrophysical parameters of the layers decreases with an increase in the number of evaluated parameters and an increase in the noise level. The accuracy of the estimates of the electrophysical parameters of the layers also decreases with a decrease in their relative permittivity and thickness. The results of experimental studies confirm the adequacy of the developed simulation model. The presented model allows for a specific measuring complex that implements the multi-frequency radio wave method of surface electromagnetic waves, to quantify the potential possibilities for the accuracy of reconstruction of the electrophysical and geometric parameters of multilayer dielectric materials and coatings. Experimental investigations and simulation results of a multilayer dielectric coating demonstrated the theoretical capabilities gained relative error permittivity and thickness of the individual layers with relative error not greater than 10 %, with a measurement bandwidth of 1 GHz and RMS of noise level 0,003–0,004.

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