Speed Plane Research Articles

Experimental and numerical modeling of the high speed planing vessel motion

In this paper, the motion of a high speed vessel with planing hull has been investigated using experimental and numerical methods. The aim of this investigation was to compare the results of the model towing test with the numerical results obtained in the Savitsky method.The most important issue in numerical modeling of a planing vessel is to determine its continuous motion conditions, such as trim and draught. Comparing the results, it is concluded that they are in a non-variant range in spite of uncertainties of continuous motion and hence modeling of the positions. Therefore, it could be expected that with more complete modeling, the study of the vessel motion conditions becomes possible, especially for high speed vessels.

Diagnosis of open‐switch faults in variable speed drives by stator current analysis and pattern recognition

This study addresses the problem of detection and isolation of open-switch faults in voltage source inverters by processing the stator current measurements. First, the resulting post-fault trajectories for the stator currents are analytically derived for single and concurrent faults (21 classes) by using Fourier series. This analysis motivated the proposed approach, which is based on the resulting pattern of the stator currents in the dq -frame after a fault, where a histogram of the trajectory is calculated by dividing the plane in 24 equally spaced sectors. From the calculated histogram, a distinctive signature is associated to each fault trajectory in the dq -plane. Single and double faults in the power semi-conductors are analysed that all provide linearly independent signatures for fault isolation. The proposed isolation methodology is independent of the load torque (system disturbance), supply frequency and only requires the information of the stator currents. Furthermore, since the isolation stage is focused on the angle of the current trajectories in the dq -plane, open- and closed-loop configurations of a variable speed drive can be simultaneously handled. Experimental results with a test bench of 3/4 HP induction motor under single and concurrent faults validated the proposed methodology.

Modal Testing Based on Single Point Laser Continuous Plane Scanning Vibration Measurement

Vibration Measurement Jigang Wu, Bin Qin, Xuejun Li, Zengzeng Yang Hunan University of Science and Technology/Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment, jgwuhust@gmail.com Hunan University of Science and Technology/Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment, qinbin505@sina.com Hunan University of Science and Technology/Engineering Research Center of Advanced Mine Equipment, Ministry of Education, hnkjdxlxj@163.com, yzz430104@yahoo.cn Abstract A high precision and fast testing method for pure modal of vibration body by continuous constant speed plane scanning vibration measurement using single point laser doppler vibrometer is proposed. According to pure modal theory, the relationship between the vibration displacement signal which obtained by continuous scanning the free vibration string which both ends are fixed with single point laser vibrometer and the modal shapes of the string is established theoretically based on the investigation of free vibration of a string which both ends are fixed. The processing method for the actual vibration signal is investigated, and the calculating method for the upper and lower alternate envelope of vibration displacement signal is proposed. The modal test platform based on single point laser continuous constant speed plane scanning vibration measurement is put up, and the validity of the modal testing method is verified by the modal testing of thin sheet beam.

Numerical simulation of the flow around a planing body by MPS method

In the planing of a high-speed boat, it is difficult to predict the complex geometry of spray and highly deformed free surface. The scale of spray is often larger than the length of the boat and its shape changes according to the speed and attitude of boat. In the situation, it is difficult to provide computational mesh with appropriate spatial resolution in both complex spray geometry and boundary layers around the hull. This paper presents a simulation procedure of the large spray formation around a high speed planing body. The method is based on Moving Particle Semi-implicit (MPS) method with modifications for ship hydrodynamics. They are surface tension, smooth body boundary, and efficient treatment of collision between free surfaces. The paper provides examples of two-dimensional falling wedge on the free surface and three-dimensional planing wedges.

Numerical Study of Fluid Flow on Magneto-Hydrodynamic Mixed Convection in a Lid Driven Cavity having a Heated Circular Hollow Cylinder

Abstract Magneto-hydrodynamic mixed convection in a lid driven cavity along with a heated circular hollow cylinder positioned at the centre of the cavity is studied numerically. The left and right vertical walls are kept at a constant temperature T c while the top and bottom horizontal walls of the cavity are insulated. The left vertical wall is moving in its own plane of a constant speed while all other walls are fixed. A uniform magnetic field is applied to the horizontal direction normal to the moving wall. A Galerkin weighted residual finite element method with a Newton Raphson iterative algorithm is adopted to solve the governing equations. The computations are carried out for wide ranges of the Hartmann number ( Ha ) and Richardson number ( Ri ). The results are presented in the form of streamlines, isothermal lines and average Nusselt number for the aforementioned parameters. The results show that the aforesaid parameters have noticeable effect on the flow pattern and heat transfer characteristics inside the cavity.

Hull Surface Information Retrieval and Optimization of High Speed Planing Craft

Traditional approach on ship design involve the use of a method which takes a form that was earlier called the ‘general design diagram’ and is now known as the ’design spiral‘ – an iterative ship design process that allows for an increase in complexity and precision across the design cycle. Several advancements have been made towards the design spiral, however inefficient for handling complex simultaneous design changes, especially when later variable changes affect the ship's performance characteristics evaluated in earlier stages. Reviewed in this paper are several advancements in high speed planing craft design in preliminary design stage. An optimization framework for high speed planing craft is discussed which consist of surface information retrieval module, a suite of state-of-the-art optimization algorithms and standard naval architectural performance estimation tools. A summary of the implementation of the proposed hull surface information retrieval and several case studies are presented to demonstrate the capabilities of the framework.

Optimization of the ASPN Process to Bright Nitriding of Woodworking Tools Using the Taguchi Approach

The subject of the research is optimization of the parameters of the Active Screen Plasma Nitriding (ASPN) process of high speed steel planing knives used in woodworking. The Taguchi approach was applied for development of the plan of experiments and elaboration of obtained experimental results. The optimized ASPN parameters were: process duration, composition and pressure of the gaseous atmosphere, the substrate BIAS voltage and the substrate temperature. The results of the optimization procedure were verified by the tools’ behavior in the sharpening operation performed in normal industrial conditions. The ASPN technology proved to be extremely suitable for nitriding the woodworking planing tools, which because of their specific geometry, in particular extremely sharp wedge angles, could not be successfully nitrided using conventional direct current plasma nitriding method. The carried out research proved that the values of fracture toughness coefficient K Ic are in correlation with maximum spalling depths of the cutting edge measured after sharpening, and therefore may be used as a measure of the nitrided planing knives quality. Based on this criterion the optimum parameters of the ASPN process for nitriding high speed planing knives were determined.

선저 공기공급에 따른 활주형선의 저항특성 연구

A planing craft is designed specifically to achieve comparatively high speed on the surface of the water. The frictional resistance of planing craft can be reduced further by injecting air to the craft`s bottom. In this paper, the resistance characteristics of high speed planing crafts with & without air injection at the bottom were compared by sea model-test method. As a result, we conformed that planing craft with air injection has much greater the effect of resistance reduction.

A Hydrodynamic Preliminary Design Optimization Framework for High Speed Planing Craft

Ship design optimization in preliminary design stage aims to identify optimum vesseldimensions based on performance targets and design constraints simultaneously.Although vast amount of designs have been generated and evaluated since theapplication of optimization approaches to ship design, only a few of such designshave been built or “dissected” to gain a deeper understanding as to why such designstend to be optimal. In this paper an optimization framework is introduced for thedesign of high speed planing craft, which consists of a geometry module, standardperformance estimates, and a suite of state-of-the-art optimization algorithms. Singleand multiobjective optimization problem formulations are solved using the framework.Designs identified through the process of optimization are further analyzed to uncoverrelationships among the design variables that lead to better designs. An importantcontribution of this paper is to illustrate the steps involved in deriving pseudo-performance estimates and their utility in the context of preliminary design wheresuch relationships can be effectively and efficiently used to sieve through a largenumber of designs.Keywords: planing craft, optimization, hull form, small craft, innovization, ship design1. Introduction

A Hydrodynamic Preliminary Design Optimization Framework for High Speed Planing Craft

Ship design optimization in preliminary design stage aims to identify optimum vessel dimensions based on performance targets and design constraints simultaneously. Although vast amount of designs have been generated and evaluated since the application of optimization approaches to ship design, only a few of such designs have been built or "dissected" to gain a deeper understanding as to why such designs tend to be optimal. In this paper an optimization framework is introduced for the design of high speed planing craft, which consists of a geometry module, standard performance estimates, and a suite of state-of-the-art optimization algorithms. Single and multiobjective optimization problem formulations are solved using the framework. Designs identified through the process of optimization are further analyzed to uncover relationships among the design variables that lead to better designs. An important contribution of this paper is to illustrate the steps involved in deriving pseudo performance estimates and their utility in the context of preliminary design where such relationships can be effectively and efficiently used to sieve through a large number of designs.

Analytical geometry method of planetary gear trains

This paper presents an analytical geometry method for kinematics and efficiency of planetary gear trains (PGTs). The novel method which is capable of evolution and contrast analysis of mechanism kinematics, can be applied to any typical one- and two-degree-of-freedom plane PGTs containing any number of simple, compound or complex-compound planetary gear sets. The efficiency analysis of this method features a systematized and programmed process and its independence of the speed ratio. The primary contribution of this work lies in the integration of quantitative calculation, qualitative evolution and comparative analysis of kinematics of PGTs into one diagram, and in the integration of kinematics and efficiency analysis into a single method system. First, the analytical geometry method is defined, its basic properties are given, and the systematization procedure to perform kinematic analysis is demonstrated. As an application, analytical geometry diagrams of common PGTs are exhibited in the form of a list, whose kinematic characteristics and general evolution tendency are discussed. Then, with the mapping of PGTs onto the angular speed plane, the efficiency formula of analytical geometry, which has an extremely concise form, and a simple method for power flow estimation are put forward. Moreover, a general procedure is provided to analyze the efficiency and power flow. Finally, four numerical examples including a complicated eleven-link differential PGTs are given to illustrate the simpleness and intuitiveness of the analytical geometry method.

69.4: High Speed In‐Plane Switching LCD with Free Retardation

AbstractWe propose a high speed In‐Plane Switching (IPS) liquid crystal display (LCD) with free retardation and wide view property. The proposed IPS mode can considerably reduce the response time of the LC cell. The optical configuration of the proposed IPS LC cell is composed of an A‐plate and LC layer. We could achieve a fast response time without any change of an LC material in transmissive mode. The calculated and experimental results for an optical response of the proposed LC cell have shown a significant reduction of the falling time. Also, we investigated an optical configuration for wide viewing angle property of the high speed IPS LCD and compared iso‐luminance with the conventional IPS LC cell.

A computational tool for the design of ride control systems for fast planing vessels

An effective method to reduce the violent motion behaviour of fast planing vessels in waves may be found in the application of active control devices in conjunction with advanced motion control systems. This study aims to develop a computational tool for the design and optimization of these ride control systems for high speed planing monohulls. Hydrodynamic characteristics of both transom flaps and interceptors are determined by systematic series of model test experiments in the towing tank of the Laboratory of Ship Hydromechanics at the Delft University of Technology. Transom flap results at downward deflection angles are validated with formulations found in literature. In addition, experiments at up angle flap positions have been performed to increase the range of application for motion control purposes. The hydrodynamic performance of the interceptors and transom flaps are compared in order to determine their efficiency. The experimental data was implemented in a nonlinear time domain mathematical model that can predict the seakeeping behaviour of fast monohulls. Simulations demonstrate the improvement in motion behaviour of a fast planing vessel with a ride control system sailing in head waves. 2011 - IOS Press and the authors. All rights reserved.

Campbell diagrams of weakly anisotropic flexible rotors

We consider an axi-symmetric flexible rotor perturbed by dissipative, conservative and non-conservative positional forces originated at the contact with the anisotropic stator. The Campbell diagram of the unperturbed system is a mesh-like structure in the frequency–speed plane with double eigenfrequencies at the nodes. The diagram is convenient for the analysis of the travelling waves in the rotating elastic continuum. Computing sensitivities of the doublets, we find that at every particular node the unfolding of the mesh into the branches of complex eigenvalues in the first approximation is generically determined by only four 2×2 sub-blocks of the perturbing matrix. Selection of the unstable modes that cause self-excited vibrations in the subcritical speed range is governed by the exceptional points at the corners of the singular eigenvalue surfaces—‘double coffee filter’ and ‘viaduct’—which are sharply associated with the crossings of the unperturbed Campbell diagram with the definite symplectic (Krein) signature. The singularities connect the problems of wave propagation in the rotating continua with that of electromagnetic and acoustic wave propagation in non-rotating anisotropic chiral media. As mechanical examples a model of a rotating shaft with two degrees of freedom and a continuous model of a rotating circular string passing through the eyelet are studied in detail.

Spray Strip부착에 따른 고속 활주형선 저항특성 연구

The planing craft is designed specifically to achieve comparatively high speed on the surface of the water. Most of planing crafts have installed the spray strip in decreasing of wave impaction and improving motion performance of rolling and pitching et al. It is known to reduce the spray and frictional resistance by the effect of lift and improvement of wave profile in high speed. In this paper, the high speed planing crafts with & without spray strip in bottom were performed to compare the resistance performance by model-test. In conclusion, the high speed planing crafts with spray strip in bottom was proved to effect of the resistance decrement of .

Cnoidal wave solutions to Boussinesq systems

In this paper, two different techniques will be employed to study the cnoidal wave solutions of the Boussinesq systems. First, the existence of periodic travelling-wave solutions for a large family of systems is established by using a topological method. Although this result guarantees the existence of cnoidal wave solutions in a parameter region in the period and phase speed plane, it does not provide the uniqueness nor the non-existence of such solutions in other parameter regions. The explicit solutions are then found by using the Jacobi elliptic function series. Some of these explicit solutions fall in the parameter region where the cnoidal wave solutions are proved to exist, and others do not; so the method with Jacobi elliptic functions provides additional cnoidal wave solutions. In addition, the explicit solutions can be used in many ways, such as in testing numerical code and in testing the stability of these waves.

High Speed Lapping of SiC Ceramic Material with Fixed Abrasive

An experimental investigation is carried out to machine SiC ceramic material through method of high speed plane lapping with fixed abrasive. The results show that the material removal mechanism and the surface roughness are chiefly related to the granularity of abrasive and the lapping pressure for the brittle materials such as SiC ceramic. It is easily realized to machine SiC ceramic material in ductile mode with a high efficiency and a low cost using W3.5 grit under a lapping pressure of 0.1MPa and then a smooth surface with surface roughness of Ra 2.4nm can be achieved.

Heat transfer effects on the stability of low speed plane Couette-Poiseuille flow

The stability problem of low-speed plane Couette-Poiseuille flow of air under heat transfer effects is solved numerically using the linear stability theory. Stability equations obtained from two-dimensional equations of motion and their boundary conditions result in an eigenvalue problem that is solved using an efficient shoot-search technique. Variable fluid properties are accounted for both in the basic flow and the perturbation (stability) equations. A parametric study is performed in order to assess the roles of moving wall velocity and heat transfer. It is found that the moving wall velocity and the location of the critical layers play decisive roles in the instability mechanism. The flow becomes unconditionally stable whenever the moving wall velocity exceeds half of the maximum velocity in the channel. With wall heating and Mach number effects included, the flow is stabilized.

고속어선의 운동성능 개선장치 개발에 관한 연구

In spite of many efforts, in the design of high speed fishing vessel the sea-keeping performance improvement without neglection of resistance-propulsion performance by hull form itself has its limitations. In this paper, the development of sea-keeping improving appendage pitching and trim improver for high speed planing hull on behalf of the hull form of fishing vessel has been introduced. The developed appendage verified its effectiveness in the full scale test and also has been proved the better resistance performance in the model test and full scale test.

On Stability and Dynamics of Milling at Small Radial Immersion

Stability and dynamics of milling at small radial immersion are investigated. Stability charts are predicted by the Semi Discretization method. Two types of instability are predicted corresponding to quasiperiodic and periodic chatter. The quasiperiodic chatter lobes are open and distributed along the spindle speed axis only, while the periodic chatter lobes are closed curves distributed in the plane of spindle speed and depth of cut. Experiments confirm the stability predictions, revealing the two principal types of chatter, the bounded periodic chatter lobes, and some special chatter cases. The recorded tool deflections in these cutting regimes are studied. The experiments also show that the modal properties of a slender tool may depend on spindle speed.