IMU Sensor-based Vibration Measuring of Ship Sailing

Minehunters are subjected to specific sea loads due to waving and dynamical impacts associated with underwater explosion. Sea waving can be sufficiently exactly modeled by means of statistical methods. Much more problems arise from modeling impacts due to underwater explosion. Knowledge of a character of impulse loading which affects ship shaft line can make it possible to identify potential failures by means of on-line vibration measuring systems. The problem of influence of sea mine explosion on hull structure is complex and belongs to more difficult issues of ship dynamics. Underwater explosion is meant as a violent upset of balance of a given system due to detonation of explosives in water environment. A paper presents a proposal of identification of a degree of hazard the ships hull forced from underwater explosion. A theoretical analysis was made of influence of changes of hull structure in vicinity of hull. The main problem of naval vessels is a lack of dynamical requirements of stiffness of the hull. Modeled signals and hull structure were recognized within sensitive symptoms of three sub models: model of hull structure, model of impact and model of propulsion system. All sub models allow testing forces and their responses in vibration spectrum using SIMULINK software and FEM models.

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An Integrated Joint Dynamics System for Elastically Jointed Structures

ASME 1991 Computers in Engineering Conference: Volume 1 — Artificial Intelligence; Expert Systems; CAD/CAM/CAE; Computational Fluid/Thermal Engineering ◽

10.1115/cie1991-0034 ◽

1991 ◽

Author(s):

Y. Rong ◽

H. S. Tzou

Keyword(s):

Dynamic Characteristics ◽

Dynamic Performance ◽

Measuring Device ◽

Joint Friction ◽

Vibration Data ◽

Unit Structure ◽

Joint Dynamics ◽

Joint Clearances ◽

Stochastic Simulator ◽

Vibration Measuring

Abstract The dynamic behavior of elastic joints strongly affect the dynamic performance of a jointed mechanical system. The dynamic contacts introduced by joint clearances create a system with nonlinear characteristics. Special effort needs to be made to study jointed mechanical systems. This paper presents an integrated joint dynamics system, which can be used to predict the dynamic characteristics of a newly designed structure, or to analyze an existing jointed structure. This joint dynamics system can also be applied as a real time monitoring and diagnosis system when it is connected with a vibration measuring device. The joint dynamics system includes: 1) a theoretical model of jointed structures, in which the joint clearance and joint friction effects are considered; 2) a stochastic simulator which is used to generate vibration data and evaluate system dynamic characteristics; 3) a diagnostic monitoring algorithm for vibration state detection; and 4) a forecasting vibration control scheme. The joint dynamics system is applied to the dynamic analysis of a truss-cell unit structure. The results presented in this paper show that the joint dynamics system is effective.

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