In order to design a tubular joint to carry a larger load and to possess a longer life, the prime objective of design would be to reduce stress concentration factor at the intersection of the joint; one method to achieve the same is to stiffen the joint with internal ring stiffeners. This paper presents results of the stress analysis for stress distribution, along the intersection of internally ring-stiffened tubular T-joints, under the action of axial and in-plane/out-of-plane (bending) loads, using degenerate shell elements. The stress analyses results are obtained using the general-purpose finite element package called ABAQUS. Post-processing of results has been facilitated by other small programs developed for the purpose. The nominal brace stress and the maximum principal stress values have been used for stress concentration factor computations. The effects of stiffener size, location, number, thickness (τ) and thinness (γ) ratios have been investigated, and the results validated with known analytical and experimental investigations. A comparison of the results obtained from finite element analysis, and experimental results of the Canadian Cooperative Fatigue Studies Program, carried out at Memorial University and University of Waterloo, is also made. The results obtained indicate that stiffening can considerably reduce the stress concentration in joints, and thus increase the load-carrying capacity of tubular T-joints.

1.
Aaghaakouchak, A. A., and Dharmavasan, S., 1990, “Stress Analysis of Unstiffened and Stiffened Tubular Joints Using Improved Finite Element Model of Intersection,” Proceedings of the Ninth International Conference on Offshore Mechanics and Arctic Engineering, Vol. III, Part A, Houston, TX, pp. 321–328.
2.
ABAQUS User’s Manual, 1992, Hibbit, Karlsson and Sorensen, Inc., Providence, RI.
3.
Camisetti, C., 1987, “Strain Gauge Measurements During a Fatigue Test of a Y Offshore Tubular Joint,” International Offshore Conference on Steel in Marine Structures, Paper TS 12, Delft, The Netherlands, pp. 405–429.
4.
Dharmavasan, S., and Aaghaakouchak, A. A., 1988, “Stress Concentrations in Tubular Joints Stiffened by Internal Ring Stiffeners,” Proceedings of the Seventh International Conference on Offshore Mechanics and Arctic Engineering, Houston, TX, pp. 141–148.
5.
Nwosu, D. I., 1993, “Fatigue Strength Analysis of Offshore Tubular Welded Joints Under Constant Amplitude Loading: Local Strain and Fracture Mechanics Approach,” Ph.D. thesis, Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John’s Newfoundland, Canada.
6.
Nwosu
D. I.
,
Swamidas
A. S. J.
, and
Munaswamy
K.
,
1993
, “
Numerical Stress Analysis for Fatigue Evaluation of Tubular Welded Joints
,”
Canadian Journal of Civil Engineering
, Vol.
20
, No.
2
, pp.
269
286
.
7.
Ramachandra, M. D. S., Madhava, R. A. G., Gandhi, P., Thandavamoorthy, T. S., Pant, P. K., and Murty, V. S. R., 1991, “Analytical and Experimental Investigations on Internally Ring Stiffened Steel Tubular Joints,” International Symposium on Fatigue and Fracture in Steel and Concrete Structures, Vol. 2, Madras, India, pp. 715–728.
8.
Recho, N., Andreau, E., Bouet, J., and Palamas, J., 1987, “Evaluation of Stress Concentration Factors in Ring-Stiffened Tubular Joints,” International Offshore Conference on Steel in Marine Structures, Paper TS 9, Delft, The Netherlands, pp. 363–375.
9.
Sawada, Y., Idogaki, S., and Sekita, K., 1979, “Static and Fatigue Tests on T-Joints Stiffened by Internal Ring,” Proceedings Offshore Technology Conference, Paper 3422, Houston, TX, pp. 563–568.
This content is only available via PDF.
You do not currently have access to this content.