Method for evaluating yield strength under extreme working condition of ship tail energy-saving conduit
A technology of ultimate working condition and yield strength, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve problems such as large tail slamming load, structural strength evaluation standards for unenergy-saving conduits, and achieve the effect of ensuring safety
Inactive Publication Date: 2018-08-17
708TH RES INST OF CSSC
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Problems solved by technology
Energy-saving ducts are usually located below the water surface and are subject to complex external environmental loads, especially when the ship is subjected to a large tail slamming load when it pitches under extreme conditions such as encountering severe sea conditions, and is subjected to lateral flow when the rudder is turned. Side thrust loads under action, with a certain risk of damage
At present, classification societies at home and abroad have no structural strength assessment standards and guidelines for this type of energy-saving duct
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[0053] In further embodiments of the present invention, please continue to refer to Figure 5 As shown, taking the slamming load on the bottom of the tail energy-saving duct as an example, the simplified calculation model of the tail energy-saving duct is a movable 5-node plane straight-rod rigid frame model, which is subjected to a uniformly distributed slamming load. The moment of inertia of the plane straight rod frame is equal to the moment of inertia of the wing-shaped section of the tail energy-saving duct, and the two ends of the plane straight rod frame are rigidly fixed. Establish the mechanical balance equation, calculate the bending moment at the lower end of the plane straight rod frame by the displacement method, and derive the minimum section modulus value required for the airfoil section of the tail energy-saving duct according to the allowable value of the material yield strength. The balance equation is:
[0054]
[0055] Among them, M 21 Is the bending moment of...
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The invention discloses a method for evaluating yield strength under an extreme working condition of a ship tail energy-saving conduit. The method comprises the steps of calculating slamming load received by a structural outer panel of a ship tail under the extreme working condition when longitudinal shaking occurs, calculating lateral direction thrust load of incoming flow on the energy-saving conduit of the ship tail during the steering operation, determining whether or not the geometric shape of the airfoil profile of the energy-saving conduit of the ship tail is reasonable, modifying the geometric shape of the airfoil profile, establishing an finite element model of the energy-saving conduit of the ship tail, respectively applying the slamming load and the lateral thrust load on the finite element model and obtaining the stress response of the energy-saving conduit of ship tail under slamming load action and / or the lateral thrust load action through finite element analysis. Preliminary evaluating is conducted on the rationality of the shape of the airfoil profile of the energy-saving conduit, the structural rigidity problem of the energy-saving conduit can be predicted in advance, and an excessive plate thickness requirement caused by an unreasonable shape scale in subsequent finite element calculation is avoided.
Description
Technical field [0001] The invention relates to the technical field of energy-saving ducts at the stern of a ship, in particular to a method for evaluating the yield strength of an energy-saving duct at the stern of a ship under extreme working conditions. Background technique [0002] With the development of large-scale ships and the increasing requirements for energy conservation and environmental protection, more and more ships are equipped with energy-saving ducts at the stern to improve or improve the propulsion efficiency of the propellers by changing the flow field at the stern. [0003] The ship energy-saving duct is a cylindrical thin-walled reinforced structure, divided into two main forms: unilateral duct and double duct. Energy-saving ducts are usually located below the water surface and bear complex external environmental loads, especially when the ship is subject to heavy tail slamming loads under extreme conditions such as severe sea conditions and pitching, as well ...
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IPC IPC(8): G06F17/50
CPCG06F30/23G06F2119/06
Inventor 吴嘉蒙刘奕谦蔡诗剑于海
Owner 708TH RES INST OF CSSC