Browsing by Author "Murugan, N."

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Effect of grooves on the static strength of tubular T joints of offshore jacket structures
(Elsevier Ltd, 2019) Murugan, N.; Kaliveeran, V.; Nagaraj, M.K.
The present research work deals with effect of grooves on static strength and stiffness of tubular T joints of offshore jacket structures. Tubular structures are commonly employed in offshore jacket platforms due to better mechanical properties and economic advantages. The tubular T model considered for this study has chord dimensions of 1000 mm length, diameter 102 mm and thickness 5 mm and brace dimensions of 388 mm length, diameter 55 mm and thickness 4 mm. Material used for present analysis is Steel with Young's modulus of 210 GPa and the Poisson ratio of 0.3. Three-dimensional finite element analysis has been carried out to investigate the effect of grooves placed over thickened chord section on the static strength of tubular T joints subjected to axial compressive load. In the present study, unstiffened tubular T joint is analysed and compared with stiffened tubular T joints to observe the improvement in the static strength of the tubular T joints. The groove configurations considered are: 5 circumferential grooves at 16.5 mm spacing, 3 circumferential grooves at 16.5 mm spacing and 3 circumferential grooves at 33 mm spacing. The grooves were having the dimension of 1 Ã— 1 mm, 2 Ã— 2 mm were used for the analysis. The joint local stiffness of ungrooved tubular T joint is 116.43 N/mm. The grooved configuration increases the joint local stiffness by more than 250 percent. Â© 2019 Elsevier Ltd. All rights reserved.
Experimental and Numerical Studies on the Stiffening of Tubular T-joint of Offshore Jacket Structures
(Springer Science and Business Media Deutschland GmbH, 2024) Murugan, N.; Kaliveeran, V.; Raveesh, R.M.; Kundapura, S.
Present study investigates the stiffening effect on the behavior of tubular T-joints in offshore platform jacket structures subjected to axial compression. Stiffening is crucial to enhance the structures' strength and lifetime. Tubular cross section structures are preferred due to their mechanical properties and cost-efficiency. The study introduces an innovative technique by adding stiffeners at the interface between braces and chords to effectively distribute loads from multiple directions. The T-joint specimen used has specific dimensions: Chord length 400 mm, brace length 200 mm, chord diameter 100 mm, brace diameter 50 mm, chord thickness 4 mm, and brace thickness 3 mm. Experimental tests and Numerical simulations were conducted to measure failure loads for both stiffened and unstiffened T-joints. Stiffened configurations (4, 6, and 8 strips) has a notable impact on the ultimate capacity of the T-joint, showcasing an increase in strength compared to the unstiffened joint. Stiffened joints showed a significant increase in ultimate strength compared to unstiffened joints, with improvements ranging from 67.18 to 73.33% for different stiffener configurations. Joint local stiffness also improved substantially, with percentage increases ranging from 67.03 to 140.80% for various stiffener configurations. Present research work demonstrates the positive impact of stiffeners on tubular T-joints, improving their strength and stiffness while showing strong agreement between numerical simulations and experimental results and the study also concludes that the addition of stiffeners effectively enhances the ultimate capacity and local stiffness of tubular T-joints. These findings emphasize the effectiveness of the proposed reinforcement strategies for optimizing tubular T-joints in offshore structures. © The Author(s), under exclusive licence to Shiraz University 2023.
Experimental Investigation of the Behavior of Tubular T-Joint of Jacket Structures
(Springer, 2024) Murugan, N.; Kaliveeran, V.; Kundapura, S.
This study deals with a preliminary experimental study to examine the behavior of tubular T-joint of Jacket structures under compressive load, which is helpful for further study of reinforcement in T-joints for strengthening. A specimen of T-joint with geometric dimensions of chord length = 494 mm, chord diameter = 141 mm, chord thickness = 5 mm, and brace length = 237 mm, brace diameter = 90 mm, brace thickness = 4.5 mm was considered for this study. The specimen is subjected to axial compressive load which is applied from the top end of the brace member. The ends of the chord member are in simply supported condition. The experiment is conducted in a 40 T UTM machine. The loads are applied with an interval of 50 kgf starting from zero to the yield load of 9,600 kgf. The experimental setup, specimen details, and the relevant results (load-deformation relationship and failure mechanism) are presented. The findings of the study, i.e., local joint deformation behavior under compressive load, are presented graphically. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.