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Ship and boat shafting service life predicating method on the basis of vibration fatigue coupling analysis

A coupling analysis and vibration fatigue technology, applied in the field of marine power plant, can solve the problems of shafting life prediction complexity, reduce the natural frequency of the structure, affect the vibration characteristics of the structure, etc. predicted effect

Inactive Publication Date: 2014-06-04
ZHENJIANG WATERCRAFT COLLEGE OF PLA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, for the life prediction of ship shafting, the existing methods rarely involve
The main reasons are: first, the current calibration standard, such as the allowable stress is usually derived from the fatigue strength of the shaft, as long as the standard is met, it is usually considered that the shaft has an infinite life, obviously, this is not scientific enough, and It is not targeted; the second is that because of the environment in which the shafting is located, the life prediction of the shafting itself has a certain complexity
Under the action of dynamic load, the shafting of the ship will vibrate, and the vibration will produce alternating stress. If it is in the environment of alternating stress for a long time, the structure will suffer fatigue damage; in addition, the existence of fatigue damage reduces the structural stiffness and reduces the The natural frequency of the structure, which affects the vibration characteristics of the structure

Method used

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  • Ship and boat shafting service life predicating method on the basis of vibration fatigue coupling analysis
  • Ship and boat shafting service life predicating method on the basis of vibration fatigue coupling analysis
  • Ship and boat shafting service life predicating method on the basis of vibration fatigue coupling analysis

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Embodiment

[0051] 1. Description of the embodiment

[0052] The propeller of a ship’s two-stroke diesel engine can be simulated by a single-mass torsional vibration system, such as figure 1 shown. Torsional vibration stiffness K when the shaft is not in use 0 =94.336MNm / rad, torsion section coefficient W p =0.0260m 3 , the damping ratio of the shaft ξ=0.1, the moment of inertia of the propeller I=31420Kg m 3 , the periodic disturbance torque T=167.428sin12.4tKN·m acting on the shaft (that is, the periodic disturbance torque amplitude T 0 =167.428KN·m).

[0053] The shaft fatigue performance curve satisfies: i.e. C=10 11 , m=0.75. The diesel engine is a two-stroke, and one stress cycle makes one revolution, so the diesel engine speed is The number of stress cycles in 1 hour is n r ·60=118.4·60=7104 times, for the sake of clarity, the units of life in the following are converted into hours.

[0054] 2. Calculation results

[0055] The natural frequency of the axis when not in...

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Abstract

The invention discloses a ship and boat shafting service life predicating method on the basis of vibration fatigue coupling analysis. The method comprises the steps of selecting a measuring time point ti, measuring the inherent frequency omega i (for n times of measurements, i=1, 2, 3, ..., and n and i are positive integers) of a ship and boat shafting located in the measuring time point ti, then, calculating the expected fatigue service life Ni when the ship and boat shafting is located in the measuring time ti, and finally calculating the remaining service life Mi when the ship and boat shafting is located in the measuring time ti. The method overcomes the defects of an existing method, starts from a ship and boat shafting model, calculates the service life of the ship and boat shafting on the basis of vibration and fatigue coupling environments, solves the problem that calculation and predication of the ship and boat shafting service life are not involved in the prior art, is easy to understand and easy to realize, and is more suitable for calculation and prediction of the remaining service life of the ship and boat shafting.

Description

technical field [0001] The invention relates to a life prediction method, in particular to a life prediction method for a shafting of a ship based on vibration fatigue coupling analysis, and belongs to the technical field of ship power devices. Background technique [0002] During the sailing of the ship, the vibration of the shaft system is one of the important factors affecting the safe operation of the ship's power plant. If it is not effectively controlled, there will be a series of serious consequences, such as the fracture of the shaft system. In order to make a correct evaluation of the vibration of the shafting and avoid the occurrence of damage accidents, not only detailed vibration calculations should be carried out in the design stage, but also vibration tests should be carried out in the operation stage to check whether the vibration characteristics of the power plant meet the specified standards. Many researchers at home and abroad have conducted in-depth discus...

Claims

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Application Information

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IPC IPC(8): G01M13/02G01H17/00
Inventor 董华玉杨智翟链
Owner ZHENJIANG WATERCRAFT COLLEGE OF PLA
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