Modeling the Effects of Underwater Detonation Wave

2013 ◽  
Vol 588 ◽  
pp. 175-183
Author(s):  
Andrzej Grządziela

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.

2014 ◽  
Vol 1036 ◽  
pp. 189-194
Author(s):  
Andrzej Grządziela ◽  
Bogdan Szturomski ◽  
Marcin Kluczyk

The paper presents problems of modeling the ship’s hull subjected to the load of shock wave associated with non-contact underwater explosion. The article presents equations for describing the parameters of shock wave subjected to an impulse load. The paper presents a proposal of identification of a degree of hazard the ship’s hull forced from underwater explosion. A theoretical analysis was made of influence of changes of hull structure in vicinity of 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. The results of testing allowed performing simulations of a similar nature to the actual loads of underwater explosions. Virtual model of the hull of the ship responds in a similar manner to the real impacts.


2007 ◽  
Vol 14 (3) ◽  
pp. 12-20 ◽  
Author(s):  
Andrzej Grządziela

An analysis of possible assessment of hazards to ship shaft line, resulting from impulse load This paper presents a proposal of identification of a degree of hazard to ship shaft line due to impulse load caused by underwater explosion. A theoretical analysis was made of influence of changes in co-axiality of shafts on second-kind critical velocities resulting from elastic deformations of hull structure in vicinity of shaft bearing foundations. Results are presented of pilotage tests of underwater explosion performed on training water area. A preliminary mathematical model of underwater explosion is given with taking into account mass of explosives and distance from the tested object. The drawn conclusions show a way of identification of hazard to shaft line by using spectral analysis and time - runs of vibration signals recorded at shaft bearings.


Author(s):  
M.A. Gribelyuk ◽  
M. Rühle

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.


Mechanik ◽  
2018 ◽  
Vol 91 (7) ◽  
pp. 498-500 ◽  
Author(s):  
Stanisław Adamczak ◽  
Mateusz Wrzochal

Roller bearing manufacturers have individual bearing vibration monitoring systems, consisting of several key components. Despite the fact that the principle of operation of these systems is the same, they differ from each other with some constructional solutions, whereas the type of construction used has an impact on the accuracy of measuring vibrations of a rolling bearing.


2014 ◽  
pp. 9-15
Author(s):  
Chris Papageorgiou ◽  
Theodore Laopoulos

The rapid growth of powerful single-chip microcomputers for monitoring and data acquisition applications permits nowadays the design of advanced measuring systems. The work reported here is presenting an advanced on-line monitoring configuration in order to improve the performance and extend the lifetime of ultrasonic transducers by applying an automated testing and calibration technique. The operation of this instrumentation system is based on the fast measurement of frequency and amplitude, performed by the proposed configuration. The combination of this information with the time of flight of each pulse-train is then used to derive practically all characteristics of ultrasonic transducers. Due to its low cost and small size, the system can be used either for characterization and classification of transducers, or as a self-testing and automated calibration section within any high performance ultrasonic system.


2021 ◽  
Vol 831 (1) ◽  
pp. 012064
Author(s):  
Long Chen ◽  
Yan Liu ◽  
Jing Lv ◽  
Xiangfeng Kong ◽  
Jingru Wang

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