Capsizing Performance of Dead Ship Stability for Damaged Ships

2021 ◽  
Vol 55 (1) ◽  
pp. 115-126
Author(s):  
Lifen Hu ◽  
Chen Yao ◽  
Wubin Li ◽  
Xiangyang Wang ◽  
Zhongyu Sun
Keyword(s):  
Time Domain ◽  
Probability Model ◽  
Ship Stability ◽  
Significant Development ◽  
Capsizing Probability ◽  
Time Calculation ◽  
The Difference ◽  
The Time Domain ◽  
Visual Basic 6.0 ◽  
Curve Solution

AbstractThis study proposes a method for combining capsizing probability and flooding process to investigate the time-domain dead ship stability of a damaged ship. It focuses on a nonlinear righting lever GZ curve solution in the following aspects: one aspect subjects the influence of damaged tanks on a hull shape to the wind and wave, and the other aspect is based on a real-time calculation of the GZ curve. According to 1‐degree-of-freedom rolling equation, the damaged capsizing probability model is established through fourth-order Runge-Kutta algorithm and Monte Carlo simulation. Also, the model solution is applied on the basis of Visual Basic 6.0 language, and the results are compared with the NAPA platform. The most significant development in this study is combining time-domain flooding process and capsizing probability calculation. To verify the proposed methods, two damaged fishery bureau vessels are used as the sample ships. Results of time-domain capsizing probability under different loading conditions are compared, and the difference and its possible reasons are analyzed.

scholarly journals Design of Two Novel Dual Band-Notched UWB Antennas

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Bing Li ◽  
Jing-song Hong
Keyword(s):  
Time Domain ◽  
Simple Structure ◽  
The Other ◽  
Ultra Wideband ◽  
Dual Band ◽  
Uwb Antennas ◽  
Monopole Antennas ◽  
Printed Monopole ◽  
The Difference ◽  
The Time Domain

Two novel dual band-notched ultra-wideband (UWB) printed monopole antennas with simple structure and small size are presented. The size of both antennas is25×25×0.8 mm3. The bandwidth of one of the proposed antenna can be from 2.7 GHz to 36.8 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 5.14–5.94 GHz for WLAN applications. The bandwidth of the other is ranging for 2.7 to 41.1 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 4.8–5.9 GHz for WLAN applications. Bandwidths of the antennas are about 512% and 455% wider than those of conventional band-notched UWB antennas, respectively. In addition, the time-domain characteristics of the two antennas are investigated to show the difference between both antennas.

scholarly journals A Method for the Analysis of Interference from DME to ATCRBS in the Time Domain

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 393 ◽  
Author(s):  
Guofeng Jiang ◽  
Yangyu Fan ◽  
Hongbo Yuan ◽  
Pengliang Yuan
Keyword(s):  
Time Domain ◽  
Traffic Control ◽  
Initial Time ◽  
Analysis Method ◽  
Operating Modes ◽  
The Monte Carlo Method ◽  
The Difference ◽  
The Time Domain ◽  
Overlap Method ◽  
Recurrence Frequency

Analysis of the coexistence of two or more types of equipment is increasingly important. However, at present studies on the analysis method in the time domain are scant. Therefore, the aim of this paper is to explore the characteristics of signals and relations between interfering and desired signals in the time domain. Based on the periodicity of a signal, this paper presents a Periodic Pulse Overlap Method (PPOM). Using PPOM to analyze the interference from Distance Measuring Equipment (DME) to Air Traffic Control Radar Beacon System (ATCRBS) in the time domain, we obtain almost the same result as that based on the Monte Carlo Method (MCM). Furthermore, we discover the measures to reduce or even avoid interference, such as changing the Pulse Recurrence Frequency (PRF), adjusting the difference of initial time, and switching the operating modes of the equipment.

The Direct Evaluation Method of Dead Ship Stability for Intact Ship

2019 ◽  
Vol 161 (A3) ◽  
Keyword(s):  
Second Generation ◽  
Evaluation Method ◽  
Stability Criteria ◽  
Ship Stability ◽  
Direct Evaluation ◽  
Intact Stability ◽  
Capsizing Probability ◽  
The Dead ◽  
The Difference ◽  
Effective Wave

The International Maritime Organization is currently establishing second generation intact stability criteria, the dead ship stability is considered one important criterion, so the development of its direct stability assessment regulation has become a topic undergoing close review. In this paper a peak-over-threshold (POT) method is proposed to evaluate the dead ship stability, which focuses on the statistical extrapolation that exceed the threshold, also the traditional Monte Carlo simulation is carried out to approve the method. On the basis of verification calculation of the sample ship CEHIPAR2792, the capsizing probability of a certain warship is also conducted. Moreover, the influence of initial stability height GM and effective wave slope coefficient on the capsizing probability is analysed. The results and the possible reason for the difference are examined. This study is expected to provide technical support for the second-generation stability criteria and establish the capsizing probability of damaged dead ship stability.

Finite Element Velocity Perturbation Application in Investigating Compressor Dovetail Fretting in Time Domain

2020 ◽  
Author(s):  
Loc Q. Duong ◽  
Olivier J. Lamicq
Keyword(s):  
Finite Element ◽  
Time Domain ◽  
Fatigue Properties ◽  
Perturbation Approach ◽  
Velocity Perturbation ◽  
Element Analysis ◽  
Factors Affecting ◽  
The Difference ◽  
The Time Domain ◽  
Contact Response

Abstract In the design of a gas turbine airfoil, avoiding resonance at all conditions is impossible. The airfoil may vibrate fiercely during resonant passages, which then may induce small oscillation motion at the disk attachment. Due to microslip at the contact regions, fretting would occur in conjunction with the reduction of material fatigue properties. This paper presents a finite element analysis using the Velocity Perturbation Method (VPM) in predicting airfoil attachment nonlinear fretting-behavior in the time domain at a resonant frequency of interest. Numerical simulation, showing design fretting fatigue characteristics based on fundamental Ruiz and Smith-Watson-Topper (SWT) criteria, is demonstrated on two models, simplified and representative. The simplified model was used for detail analysis set-up and basic post-processing while the representative model illustrated the difference in nonlinear contact response of an industrial compressor under bending and torsional modes in the time domain. This Finite Element velocity perturbation approach can be used to study the main factors affecting fretting of any two bodies in contact: load, coefficient of friction, contact geometry and impact of different frequencies or modal shapes in the time domain.

scholarly journals Dilemma and Solution of Traditional Feature Extraction Methods Based on Inertial Sensors

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Zhiqiang Peng ◽  
Yue Zhang
Keyword(s):  
Feature Extraction ◽  
Angular Velocity ◽  
Frequency Domain ◽  
Time Domain ◽  
Inertial Sensors ◽  
Extraction Methods ◽  
Feature Extraction Method ◽  
The Difference ◽  
The Time Domain ◽  
Almost All

Correctly identifying human activities is very significant in modern life. Almost all feature extraction methods are based directly on acceleration and angular velocity. However, we found that some activities have no difference in acceleration and angular velocity. Therefore, we believe that for these activities, any feature extraction method based on acceleration and angular velocity is difficult to achieve good results. After analyzing the difference of these indistinguishable movements, we propose several new features to improve accuracy of recognition. We compare the traditional features and our custom features. In addition, we examined whether the time-domain features and frequency-domain features based on acceleration and angular velocity are different. The results show that (1) our custom features significantly improve the precision of the activities that have no difference in acceleration and angular velocity; and (2) the combination of time-domain features and frequency-domain features does not significantly improve the recognition of different activities.

The Analysis of a Transmission Line Crosstalk in the Time Domain Based on First-Order Upwind

2014 ◽  
Vol 543-547 ◽  
pp. 813-816
Author(s):  
Yin Han Gao ◽  
Tian Hao Wang ◽  
Jun Dong Zhang ◽  
Kai Yu Yang ◽  
Yu Zhu
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Time Domain ◽  
Splitting Method ◽  
Discontinuous Solution ◽  
Characteristic Line ◽  
First Order ◽  
The Difference ◽  
Leapfrog Scheme ◽  
The Time Domain

This article will combine the difference scheme of first-order upwind with the multi-conductor transmission lines equation to analysis the multi-conductor transmission lines crosstalk in the time domain. First-order upwind is a finite difference algorithm in the time domain; it has a first order accuracy, in the discontinuous solution there is no non-physics-oscillation, when simulate the signal. The flux splitting method which is applied to the first-order upwind solved the problem that the characteristic line direction of the wind type make plus or minus transformation along with the coefficient, make the programming simple. In this paper, simulation results of transmission line crosstalk in this algorithm will be compared with the traditional leapfrog scheme, to verify its effectiveness.

The Direct Evaluation Method of Dead Ship Stability for Intact Ship

2019 ◽  
Vol 161 (A3) ◽  
Author(s):  
LF Hu ◽  
QZ Zhang ◽  
WY Zhang ◽  
HB Qi
Keyword(s):  
Second Generation ◽  
Evaluation Method ◽  
Stability Criteria ◽  
Ship Stability ◽  
Direct Evaluation ◽  
Intact Stability ◽  
Capsizing Probability ◽  
The Dead ◽  
The Difference ◽  
Effective Wave

The International Maritime Organization is currently establishing second generation intact stability criteria, the dead ship stability is considered one important criterion, so the development of its direct stability assessment regulation has become a topic undergoing close review. In this paper a peak-over-threshold (POT) method is proposed to evaluate the dead ship stability, which focuses on the statistical extrapolation that exceed the threshold, also the traditional Monte Carlo simulation is carried out to approve the method. On the basis of verification calculation of the sample ship CEHIPAR2792, the capsizing probability of a certain warship is also conducted. Moreover, the influence of initial stability height GM and effective wave slope coefficient on the capsizing probability is analysed. The results and the possible reason for the difference are examined. This study is expected to provide technical support for the second-generation stability criteria and establish the capsizing probability of damaged dead ship stability.

THE DIRECT EVALUATION METHOD OF DEAD SHIP STABILITY FOR INTACT SHIP

2021 ◽  
Vol 161 (A3) ◽  
Author(s):  
L F Hu ◽  
Q Z Zhang ◽  
W Y Zhang ◽  
H B Qi
Keyword(s):  
Second Generation ◽  
Evaluation Method ◽  
Stability Criteria ◽  
Ship Stability ◽  
Direct Evaluation ◽  
Intact Stability ◽  
Capsizing Probability ◽  
The Dead ◽  
The Difference ◽  
Effective Wave

The International Maritime Organization is currently establishing second generation intact stability criteria, the dead ship stability is considered one important criterion, so the development of its direct stability assessment regulation has become a topic undergoing close review. In this paper a peak-over-threshold (POT) method is proposed to evaluate the dead ship stability, which focuses on the statistical extrapolation that exceed the threshold, also the traditional Monte Carlo simulation is carried out to approve the method. On the basis of verification calculation of the sample ship CEHIPAR2792, the capsizing probability of a certain warship is also conducted. Moreover, the influence of initial stability height GM and effective wave slope coefficient Y on the capsizing probability is analysed. The results and the possible reason for the difference are examined. This study is expected to provide technical support for the second-generation stability criteria and establish the capsizing probability of damaged dead ship stability.

scholarly journals Evaluation of Unfilled Sheath in Concrete Structures Using Response Waveform in Time Domain

2021 ◽  
Vol 11 (23) ◽  
pp. 11402
Author(s):  
Kota Ikebata ◽  
Yoshikazu Kobayashi ◽  
Kenichi Oda ◽  
Katsuya Nakamura
Keyword(s):  
Time Domain ◽  
Dominant Frequency ◽  
Conventional Technique ◽  
Internal Defects ◽  
Small Defect ◽  
The Difference ◽  
A New Technique ◽  
The Time Domain ◽  
Value Changes ◽  
The Impact

The impact elastic wave method (IEW) has been applied to evaluate the thickness and internal defects of the target structure based on the dominant frequency of the response wave that is formed by the repeated reflections in the thickness direction. However, it is difficult to evaluate the size and position of the defect by IEW if the size and depth are relatively small and deep, respectively, and further, it is known that the technique is inapplicable if the target is not a plate-like structures. Therefore, the authors propose a new technique that uses Difference value as a new evaluation index to overcome the limitations of the conventional methods. Difference value shows the change of the response waveform in the time domain; it is computed by using a response waveform of the structures in sound condition as a reference. In this paper, the practicality of the Difference value is investigated by performing experiments using concrete specimens. The results of the experiments demonstrate that Difference value changes by the influence of internal defects, and Difference value evaluates the location of the relatively small defect that is difficult to evaluate by the conventional technique.

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