Transverse Structural Strength Characterization of a Deep-U Catamaran Vessel

• Author(s): Azubuike John Chuku ; Daniel Tamunodukobipi ; Charles Ugochukwu Orji ; Samson Nitonye
• Paper ID: 1706307
• Page: 387-397
• Published Date: 21-09-2024
• Published In: Iconic Research And Engineering Journals
• Publisher: IRE Journals
• e-ISSN: 2456-8880
• Volume/Issue: Volume 8 Issue 3 September-2024

Abstract

This paper sets out to characterize the transverse structural behaviour of a Cork composite hullform of a deep-U Catamaran vessel (DUC) based on the conventional transverse shear force and bending moment theory and Henky’s von-Mises Stress criteria. It considered the Transverse Still-water and Maximum Global wave induced loads on the vessel. Further, it ascertained the deformation and stresses imposed on the structure as a result of both the Still-water and wave-induced loads. The Still-water loads utilized existing conventional principles, whereas the wave-induced loads were derived from the vessel’s hydrodynamic motion characterization based on the Modified Pierson Moskowitz Spectrum for narrow banded wave and benign sea state, solved through the numerical analysis on the ANSYS. From the analysis on the global transverse shear force (kN), the hogging and sagging shear forces exhibited similar trends, with initial increases, fluctuations, sharp reversals, and gradual recoveries. Both forces reach their maximum values at different vessel width. The Still-water transverse shear force values range from -18 kN to 18 kN. at a corresponding positions at the Still-water transverse bending moment values range from -2.2 kNm to 46 kNm. The maximum global positive transverse shear force is 121 kN, occurring at -0.45m. The maximum negative shear force is -121 kN, occurring at 0.45m. The maximum positive transverse shear force is 101 kN, occurring at -0.45m. The highest negative shear force is -101 kN, occurring at 0.45m. The shear force is zero at -1.8 and 1.8 along the vessel breadth for both hogging and sagging, indicating points where there is no maximum global transverse shear force. The maximum transverse (cross-deck/local) bending moment exhibited a hogging moment at its maximum value of 170 kNm. The values decrease symmetrically as you move away from the midpoint, reaching 0 at both port and starboard (positions -1.8m and 1.8m). The sagging moment also has its peak at the midpoint, but it is lower than the hogging moment, with a maximum of 90 kNm. Similar to the hogging moment, the sagging values decrease symmetrically towards the ends, reaching 0 at vessel breadth of -1.8m and 1.8m respectively. For the maximum transverse torsional moments, the positions along the deck where the moments are measured are: -1.8m, -1.35m, -0.9m, -0.45m, 0m, 0.45m, 0.9m, 1.35m & 1.8m represent transverse positions across the breadth of the vessel. At the midpoint (across the breadth), the hogging moment starts at 0 kNm. The values initially increase slightly (11 kNm) and then decrease to a minimum of -271 kNm at 1.35m, before slightly increasing to -261 kNm at position 1.8m. The values initially decrease slightly (-6 kNm), then increase (11 kNm) before decreasing to a minimum of -261 kNm at position 1.8m. The graph indicates that torsional moments are higher towards the ends of the deck in both hogging and sagging conditions. Wave crest acting at fore and aft perpendicular of the DUC vessel hull had loads of 103kN at the midsection of hull and near the midship a load of 51.5kN at two corners on the deck surface of the vessel were applied. This resulted in the maximum total deformation of 1.8229e-004m and maximum shear stress of 1.44MPa. The equivalent Henky’s von-Mises stress criteria of 2.8677M6Pa was statically lower than the ultimate strength of 3.0MPa of the Cork composite. By this results, the structural integrity of the DUC vessel is not threatened.

Keywords

Numerical, Structural, Catamaran, Strength, von-Mises

Citations

IRE Journals:
Azubuike John Chuku , Daniel Tamunodukobipi , Charles Ugochukwu Orji , Samson Nitonye "Transverse Structural Strength Characterization of a Deep-U Catamaran Vessel" Iconic Research And Engineering Journals Volume 8 Issue 3 2024 Page 387-397

IEEE:
Azubuike John Chuku , Daniel Tamunodukobipi , Charles Ugochukwu Orji , Samson Nitonye "Transverse Structural Strength Characterization of a Deep-U Catamaran Vessel" Iconic Research And Engineering Journals, 8(3)