The design of twin-saddle supported multi-layered glass-reinforced plastic vessels—the development of a parametric equation for the maximum strain

Abstract

The maximum strain in a glass-reinforced plastic vessel, supported on rigid saddle supports, invariably occurs at the uppermost point of the support known as the saddle horn. The strain, which is in the circumferential direction, is compressive on the outside and tensile on the inside surfaces of the vessel. This can create problems in composite vessels since local cracking of the inner surface may allow liquid ingress to the glass through the matrix, with premature local failure by stress corrosion cracking. The analysis of this support problem has been solved using a double Fourier series by Tooth et al, [8], by which the maximum strain in the support region can be derived. The present paper presents a parametric study for an extensive range of vessels, in use in the process and chemical industries, using this analysis. To aid the design process the results for the crucial maximum strain values are presented in a ‘closed form’, using an equation-fitting technique. The details of the procedure used to achieve these equations should be of interest to analysts in other fields of work. Typical examples are given to illustrate the use of the derived equations for a symmetric laminate.

Keywords

saddle supports horizontal glass-reinforced plastic vessels design method composites parametric study

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References

PD 5500:2000 Unfired Fusion Welded Pressure Vessels (British Standards Institution, London).

BS 4994:1987 Design and Construction of Vessels and Tanks in Reinforced Plastic (British Standards Institution, London).

Ong

L. S.

Tooth

A. S.

Analysis of a cylindrical shell supported by two longitudinal beams

Proc. Instn Mech. Engrs, Part E, Journal of Process Mechanical Engineering, 1996, 210 (E2), 109–119.

ASME Boiler and Pressure Vessel Code, Section X, Fibreglass-reinforced Plastic Pressure Vessels, Appendices 1–5, Attachments and Supports, 1986 (American Society of Mechanical Engineers, New York).

Zick

L. P.

Stresses in large horizontal cylindrical pressure vessels on two saddle supports

Welding J. Res. Suppl., September 1951, 30, 435S–445S.

Duthie

Tooth

A. S.

The analysis of horizontal cylindrical vessels supported on saddles welded to the vessel—a comparison of theory and experiment. In Proceedings of the Third International Conference on

Pressure Vessel Technology (ICPVT-3), Tokyo, 1977, pp. 25–38 (American Society of Mechanical Engineers, New York).

Tooth

A. S.

Duthie

White

G. C.

Carmichael

Stresses in horizontal storage vessels—a comparison of theory and experiment

J. Strain Analysis, 1982, 17, 169–176.

Tooth

A. S.

Banks

W. M.

Seah

C. P.

Tolson

B. A.

The twin-saddle support of horizontal multi-layered GRP vessels—theoretical analysis, experimental work and a design approach

Proc. Instn Mech. Engrs, Part E, Journal of Process Mechanical Engineering, 1994, 208 (E1), 59–74.

Fok

W. C.

Tooth

A. S.

A procedure for equation fitting of computer-generated design data

J. Strain Analysis, 1997, 32 (5), 365–373.

10.

Banks

W. M.

Nash

D. H.

Flaherty

A. E.

Fok

W. C.

Tooth

A. S.

The derivation of a ‘best fit equation’ for maximum strains in a GRP vessel supported on twin saddles. In Proceedings of the Ninth International Conference on

Pressure Vessel Technology (ICPVT-9), Sydney, Australia, April 2000, Vol. 1, Design and Stress Analysis, Materials and Manufacturing, pp. 109–119 (American Society of Mechanical Engineers, New York).

11.

Nash

D. H.

Tooth

A. S.

The influence of the flexibility of the dished end on twin supported pressure vessels. In Proceedings of the Eighth International Conference on

Pressure Vessel Technology (ICPVT—8), Montreal, Canada, Vol. 2, Design and Analysis, 1996, pp. 55–59 (American Society of Mechanical Engineers, New York).

12.

Nash

D. H.

Local loading and saddle supports on cylindrical vessels. PhD thesis, University of Strathclyde, Glasgow, Scotland, February 1999.