Calculation method of still water shear force and bending moment based on STL model

LIU Chun-lei; YIN Yong; SUN Xiao-feng; ZHANG Xiu-feng; SHEN He-long

Volume 17 Issue 2

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LIU Chun-lei, YIN Yong, SUN Xiao-feng, ZHANG Xiu-feng, SHEN He-long. Calculation method of still water shear force and bending moment based on STL model[J]. Journal of Traffic and Transportation Engineering, 2017, 17(2): 73-82.

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LIU Chun-lei, YIN Yong, SUN Xiao-feng, ZHANG Xiu-feng, SHEN He-long. Calculation method of still water shear force and bending moment based on STL model[J]. Journal of Traffic and Transportation Engineering, 2017, 17(2): 73-82.

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Calculation method of still water shear force and bending moment based on STL model

Key Laboratory of Marine Simulation and Control of Ministry of Transport, Dalian Maritime University, Dalian 116026, Liaoning, China

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Author Bio:
LIU Chun-lei(1987-), male, doctoral student, +86-411-84729651, 18940930042@163.com

YIN Yong(1969-), male, professor, PhD, +86-411-84723925, bushyin@163.com
Received Date: 2016-11-12
Publish Date: 2017-04-25

Abstract

Abstract

To improve the calculation accuracy of ship strength, a method based on STL model was proposed to calculate still-water shear force and bending moment of ship.In calculating the total longitudinal strengths, the initial values of ship floating condition were calculated by the conventional method, and then the draught, heeling angle and trim of ship were calculated by the iteration method.The transverse section of each rib was obtained by cutting the hull according to the rib position, the area of underwater part of each section was calculated by using the Green formula, and the buoyancy curve was obtained by the longitudinal integration.The mass distribution table of each cabin was established offline by cutting the STL model of ship cabin, and the actual mass distribution of cabin was used instead of the trapezoid mass distribution to calculate the mass distribution curve.Finally, based on the distribution curves of buoyancy and mass, the bulk carriers "Taihang 128"and "SPRING COSMOS"were taken as examples tocalculate the shear forces and bending moments under 5 typical loading conditions.Calculation result shows that the average relative errors of shear forces and bending moments calculated by the proposed method and the design software NAPA of ship are about 1%, the maximum error is 2.6%, the errors are smaller, so the accuracy of proposed method is higher.The iterative algorithm of ship floating condition only needs to calculate the drainage volume and buoyancy center coordinates of ship in free floating condition, so the program is simple, stable and reliable.The proposed method is applied to any floating condition of ship, the buoyancy distribution curve of ship can be calculated by directly cutting the hull, so the proposed method makes up for the deficiency of the conventional method that can calculate only ship's longitudinal strength.By establishing the mass distribution table of ship cabins and using the actual distribution of mass instead of the traditional trapezoid distribution of mass, the calculation precision of ship strength rises, and the calculated amount reduces.
- ship engineering,
- still-water shear force,
- bending moment,
- STL model,
- free floatation,
- loading computer

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References(30)

References

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