Theoretical Analysis of the Stresses in Pipe Bends Subjected to Out-of-Plane Bending

1967 ◽  
Vol 9 (2) ◽  
pp. 115-123 ◽  
Author(s):  
R. T. Smith

Most of the experimental and theoretical work on the flexure of pipe bends has concerned bending in the plane of the bend but comparison of the results of some experiments using out-of-plane bending with calculations based on existing theories indicated a need for a more exact theoretical analysis of this form of loading. In this paper a comprehensive theoretical treatment of the elastic flexure of curved tubes already published for in-plane bending has been adapted to deal with out-of-plane bending. The equations for both forms of loading have been programmed for solution by a digital computer and a design procedure is suggested to find the maximum stresses due to combined in-plane, out-of-plane and torsional bending moments.

1963 ◽  
Vol 30 (1) ◽  
pp. 134-135
Author(s):  
E. A. Utecht

Curves are presented which give stress intensification factors for curved, thin-walled circular tubes under various combinations of in-plane and out-of-plane bending moments.


Author(s):  
R Kitching ◽  
P Myler

Tests to failure have been carried out on six smooth pipe bends constructed by hand lay-up from polyester resin and glass in the form of chopped strand mat. The failure loads under out-of-plane bending only are compared with those where this type of loading is combined with internal pressure. The results are discussed in relation to the design procedure adopted in BS 7159: 1989.


1994 ◽  
Vol 116 (2) ◽  
pp. 49-55 ◽  
Author(s):  
A. K. Soh ◽  
C. K. Soh

A parametric stress analysis of DT/X square-to-square and square-to-round tubular joints subjected to axial loads, in-plane, and out-of-plane bending moments has been performed using the finite element technique in order to provide a sound basis for using such sections in the design of complex structures. The results of this analysis are presented as a set of equations expressing the stress concentration factor as a function of the relevant geometric parameters for various loading conditions. A comparison is made between the results obtained for square-to-square and square-to-round tubular joints and those obtained for round-to-round tubular joints by other researchers. In general, the stress concentration factors for square-to-square tubular joints are the highest, followed by those of the corresponding round-to-round joints, with those of the corresponding square-to-round joints the lowest when the joints are subject to axial loads. In the case of in-plane bending moment, the stress concentration factors for square-to-square joints are generally still the highest, but followed by those of the corresponding square-to-round joints, with those of the corresponding round-to-round joints the lowest. However, the stress concentration factors for the three types of joint are comparable when they are subject to out-of-plane bending moments.


Author(s):  
Hany F. Abdalla

Ninety degree back–to–back pipe bends are extensively utilized within piping networks of modern nuclear submarines and modern turbofan aero–engines where space limitation is considered a supreme concern. According the author’s knowledge, no shakedown analysis exists for such structure based on experimental data. In the current research, the pipe bend setup analyzed is subjected to a spectrum of steady internal pressures and cyclic out–of–plane bending moments. A previously developed direct non–cyclic simplified technique, for determining elastic shakedown limit loads, is utilized to generate the elastic shakedown boundary of the analyzed structure. Comparison with the elastic shakedown boundary of the same structure, but subjected to cyclic in–plane bending moments revealed a higher shakedown boundary for the out–of–plane bending loading configuration with a maximum bending moment ratio of 1.4 within the low steady internal pressure spectrum. The ratio decreases towards the medium to high internal pressure spectrum. The simplified technique outcomes showed excellent correlation with the results of full elastic–plastic cyclic loading finite element simulations.


1971 ◽  
Vol 6 (4) ◽  
pp. 213-225 ◽  
Author(s):  
M P Bond ◽  
R Kitching

A theoretical analysis has been developed to predict stress distributions and flexibility factors associated with out-of-plane bending of multi-mitred pipe bends. The estimated range of validity of the analysis is sufficient to include most practical multi-mitred pipe bends. Tests on a large-diameter, thin-walled, three-weld right-angled multi-mitred bend were undertaken and the results closely agreed with computations based on the analysis. Predictions for both flexibility factors and overall maximum-stress ratios from the analysis were almost identical with those given by an in-plane bending theory that had been developed from a similar method of approach.


2020 ◽  
Vol 211 ◽  
pp. 110434 ◽  
Author(s):  
Chengqing Liu ◽  
Bida Zhao ◽  
Juan Yang ◽  
Qian Yi ◽  
Zeyang Yao ◽  
...  

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