scholarly journals A new mathematical hull-form with 10-shape parameters for evaluation of ship response in waves

2021 ◽  
Author(s):  
Sadaoki Matsui
Keyword(s):  
Sensitivity Analysis ◽  
Wave Loads ◽  
Shape Parameters ◽  
Hull Form ◽  
Second Moment ◽  
Explicit Function ◽  
Seakeeping Performance ◽  
Wigley Hull ◽  
Simple Evaluation ◽  
Anterior Posterior

AbstractThis study presents a new mathematical hull-form that is expressed as an explicit function with 10 hull-form parameters, which is called the Matsui hull-form in this study. The proposed hull-form was developed by expanding the modified Wigley hull-form so that the following 10 hull-form parameters can be independently varied: main dimensions $$L$$ L , $$B$$ B , $$d$$ d , fineness coefficients $${C}_{b}$$ C b , $${C}_{\mathrm{m}}$$ C m , $${C}_{\mathrm{w}}$$ C w , second moment of waterplane area coefficient $${C}_{\mathrm{w}2}$$ C w 2 , longitudinal center of buoyancy LCB and floatation LCF, and a parameter $$\beta$$ β related to anterior–posterior asymmetry. The main purpose of this hull-form is that it is utilized for the following two objects: the first is the simple evaluation of the seakeeping performance and wave loads in the early ship designing stage without any detailed offset data, and the second is a systematical study on the influence of a ship’s dimensions on the ship response in waves. This paper presents the derivation of the Matsui hull-form and the applicability of the proposed hull-from was confirmed by comparing the ship response in waves with the actual ships. Moreover, a sensitivity analysis of the ship response in waves was conducted as an example of the application of the proposed hull-form.

Some Guidance for Hull Form Selection for SWATH Ships

1988 ◽  
Vol 25 (04) ◽  
pp. 239-252
Author(s):  
G. Robed Lamb
Keyword(s):  
High Speed ◽  
Early Stage ◽  
The United States ◽  
Practical Application ◽  
Hull Form ◽  
Stage Design ◽  
Seakeeping Performance ◽  
The World ◽  
Selection For ◽  
Early Stage Design

Even though in 1987 there were only a dozen SWATH (smali-waterplane-area twin-hull) craft and ships afloat around the world, word of their markedly superior seakeeping performance is spreading rapidly. The number of SWATH vessels is likely to double within five years. As in many other areas of technology, the United States and Japan are the acknowledged leaders in the development and practical application of the SWATH concept. This paper reviews the characteristics of existing SWATH craft and ships from the standpoint of the stated seakeeping objective. Hull form differences between four SWATH craft and ships, including the Navy's SSP Kairnalino, are analyzed and interpreted. Important considerations for the early-stage design of a SWATH ship are discussed. Differences in the range of feasible hull form geometries for coastal areas and unrestricted ocean operations, and for low-speed versus moderately high-speed applications, are pointed out.

A Seakeeping Study of the UBC Series

1997 ◽  
Vol 34 (01) ◽  
pp. 10-23
Author(s):  
Sander M. Calisal ◽  
David Howard ◽  
Jon Mikkelsen
Keyword(s):  
British Columbia ◽  
Measurement Procedure ◽  
Collection System ◽  
Fishing Vessel ◽  
The West ◽  
Hull Form ◽  
University Of British Columbia ◽  
Fishing Vessels ◽  
Seakeeping Performance ◽  
The University

The University of British Columbia (UBC) and the British Columbia Research Incorporated (BCRI) collaborated to design a fishing vessel suitable for use on the west coast of Canada. This vessel, called the UBC Series parent hull form, was designed to have a large aft deck area and a volumetric coefficient comparable to those of modern Canadian fishing vessels. The resistance characteristics of this hull were improved without compromising on functionality and usable space. A resistance algorithm developed from the results for a systematic series of low-L/B displacement-type vessels, the UBC Series, was previously published (Calisal&McGreer, 1993). However, during the design process, the seakeeping performance of the vessel was never addressed. This paper describes the seakeeping performance of the UBC series in head seas. An algorithm, developed from the results of the model tests, can be used to calculate the seakeeping response of similar low L/B vessels. To calibrate the seakeeping measurement procedure, tank instrumentation, and data collection system, the ITTC Standard Seakeeping hull form (the S-175 hull form) was tested and the results were compared against published results for this hull form. The same techniques used for the standard hull form were then used to measure the seakeeping performance of the UBC Series. Possible application of the algorithm for non-UBC Series forms is also discussed.

A Taylor Expansion Approach for Computing Structural Performance Variation From Population-Based Shape Data

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Xilu Wang ◽  
Xiaoping Qian
Keyword(s):  
Taylor Expansion ◽  
Population Based ◽  
Shape Modeling ◽  
Structural Performance ◽  
Shape Parameters ◽  
Explicit Function ◽  
Performance Variation ◽  
Statistical Shape ◽  
Function Relationship ◽  
Shape Data

Rapid advancement of sensor technologies and computing power has led to wide availability of massive population-based shape data. In this paper, we present a Taylor expansion-based method for computing structural performance variation over its shape population. The proposed method consists of four steps: (1) learning the shape parameters and their probabilistic distributions through the statistical shape modeling (SSM), (2) deriving analytical sensitivity of structural performance over shape parameter, (3) approximating the explicit function relationship between the finite element (FE) solution and the shape parameters through Taylor expansion, and (4) computing the performance variation by the explicit function relationship. To overcome the potential inaccuracy of Taylor expansion for highly nonlinear problems, a multipoint Taylor expansion technique is proposed, where the parameter space is partitioned into different regions and multiple Taylor expansions are locally conducted. It works especially well when combined with the dimensional reduction of the principal component analysis (PCA) in the statistical shape modeling. Numerical studies illustrate the accuracy and efficiency of this method.

Calculating Individual and Total Muscular Translational Stiffness: A Knee Example

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Joshua G. A. Cashaback ◽  
Michael R. Pierrynowski ◽  
Jim R. Potvin
Keyword(s):  
Experimental Data ◽  
Sensitivity Analysis ◽  
Knee Joint ◽  
Knee Flexion ◽  
Pennation Angle ◽  
Biomechanical Models ◽  
The Individual ◽  
Full Activation ◽  
Translational Stiffness ◽  
Anterior Posterior

Research suggests that the knee joint may be dependent on an individual muscle's translational stiffness (KT) of the surrounding musculature to prevent or compensate for ligament tearing. Our primary goal was to develop an equation that calculates KT. We successfully derived such an equation that requires as input: a muscle's coordinates, force, and stiffness acting along its line of action. This equation can also be used to estimate the total joint muscular KT, in three orthogonal axes (AP: anterior-posterior; SI: superior-inferior; ML: medial-lateral), by summating individual muscle KT contributions for each axis. We then compared the estimates of our equation, using a commonly used knee model as input, to experimental data. Our total muscular KT predictions (44.0 N/mm), along the anterior/posterior axis (AP), matched the experimental data (52.2 N/mm) and was well within the expected variability (22.6 N/mm). We then estimated the total and individual muscular KT in two postures (0 deg and 90 deg of knee flexion), with muscles mathematically set to full activation. For both postures, total muscular KT was greatest along the SI-axis. The extensors provided the greatest KT for each posture and axis. Finally, we performed a sensitivity analysis to explore the influence of each input on the equation. It was found that pennation angle had the largest effect on SI KT, while muscle line of action coordinates largely influenced AP and ML muscular KT. This equation can be easily embedded within biomechanical models to calculate the individual and total muscular KT for any joint.

scholarly journals Effects of Hull Form Variations on Resistance and Seakeeping Performance of Planing Hulls with and without Incoming Regular Waves

2014 ◽  
Vol 51 (5) ◽  
pp. 369-379 ◽  
Author(s):  
Dong Jin Kim ◽  
Sun Young Kim ◽  
Seong Hwan Kim ◽  
Jeong Hwa Seo ◽  
Shin Hyung Rhee
Keyword(s):  
Regular Waves ◽  
Hull Form ◽  
Seakeeping Performance

Probabilistic Optimal Design Using Second Moment Criteria

1988 ◽  
Vol 110 (3) ◽  
pp. 324-329 ◽  
Author(s):  
A. D. Belegundu
Keyword(s):  
Finite Element Method ◽  
Sensitivity Analysis ◽  
Optimal Design ◽  
Design Sensitivity ◽  
Design Criterion ◽  
Second Order ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Programming Technique ◽  
Second Moment

Probability-based optimal design of structures is presented. The emphasis here is to develop a practical approach to optimal design given random design parameters. The method is applicable to structures which are modeled using the finite element method. The Hasofer-Lind (H-L) second-moment design criterion is used to formulate the general design problem. A method for calculating the sensitivity coefficients is presented, which involves second-order design sensitivity analysis. The importance of second order derivatives is established. A nonlinear programming technique is used to solve the problem. Numerical results are presented, where stiffness parameters are treated as random variables.

SENSITIVITY ANALYSIS OF COMPOSITE LAMINATED PLATES USING THE MESHLESS IN THE STATE SPACE FRAMEWORK

2013 ◽  
Vol 10 (05) ◽  
pp. 1350023 ◽  
Author(s):  
D. H. LI ◽  
G. H. QING
Keyword(s):  
Sensitivity Analysis ◽  
State Space ◽  
Governing Equation ◽  
Laminated Plates ◽  
The State ◽  
Response Analysis ◽  
Static Response ◽  
Shape Parameters ◽  
Composite Laminated Plates ◽  
Sensitivity Coefficients

A hybrid governing equation is presented by using the meshless method with radial basis functions for the response and sensitivity analysis of composite laminated plates in the state space framework. Analytical method (AM), semi-analytical (SA) and finite difference (FD) expresses of the hybrid governing equation are also derived for the sensitivity analysis. Numerical examples are consisted of the static response analysis, dynamic response analysis and their sensitivity analysis. The sensitivity coefficients of the static response and natural frequency are obtained by AM, SA and FD with respect to the material prosperities and the shape parameters of the cross-ply composite laminated plates. One of the main advantages of the hybrid governing equation in the response analysis and sensitivity analysis is that the convoluted algorithm can be avoided in sensitivity analysis, and the response quantities and the sensitivity coefficients are obtained simultaneously.

Seakeeping and Added Resistance of IACC Yachts by a Three-Dimensional Panel Method

1993 ◽  
Author(s):  
P. D. Sclavounos ◽  
D. E. Nakos
Keyword(s):  
Sensitivity Analysis ◽  
Potential Flow ◽  
Three Dimensional ◽  
Panel Method ◽  
Radius Of Gyration ◽  
Experimental Measurements ◽  
Shape Parameters ◽  
Added Resistance ◽  
Pitch Motion ◽  
America’S Cup

A three-dimensional panel method developed for the prediction of the seakeeping properties of conventional ships has been extended to predict the motions and added resistance of IACC Yachts. The method solves the three dimensional unsteady potential flow around the yacht in monochromatic oblique waves. Predicted quantities include the heave and pitch motion amplitudes and phases and added resistance over a broad range of wave frequencies yacht speeds. Computations have been carried out for a series of IACC hull shapes studied by PACT (Partnership for America's Cup Technology) and correlations with experimental measurements are found to be very satisfactory. The same method was also used to study the added-resistance properties of hull shapes supplied by the America3 Foundation. A sensitivity analysis was carried out of the added resistance on the principal yacht hull shape parameters, including the slenderness, displacement, LCB­LCF separation and pitch radius of gyration.

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