Polar Icebreaker Research Articles

Optimization design and sensitivity analysis of diesel/battery hybrid propulsion system for polar icebreaker

Objectives For the economic and environmental requirements of polar ice-breakers, a hybrid propulsion system composed of diesel generator sets and a rechargeable battery is proposed. Methods First, the resistance model is established on the basis of ice scale, and the energy flow model of the diesel/battery hybrid propulsion system is established using the inverse simulation method. The component parameters of the propulsion system are then optimized on the basis of an elitist nondominated sorting genetic algorithm-II (NSGA-II) with annual fuel and total cost of entire life cycle as the optimization objectives, and the optimal design is obtained via the technique for order of preference by similarity to ideal solution (TOPSIS) method. Finally, the sensitivity analysis of the optimization objectives to seven design parameters is conducted. Results The results show that the optimal design scheme of the diesel/battery hybrid propulsion system can save 1.89% in fuel consumption compared with the traditional diesel-electric propulsion system, and the pure electric navigation time accounts for 31.22% of the whole voyage, but the rechargeable battery reduces the economy of the system. The sensitivity analysis shows that the optimization objectives (annual fuel and total cost of entire life cycle) of the hybrid propulsion system are sensitive to main engine capacity, number of battery packs and battery state of charge, while less sensitive to reducer ratio, motor capacity and propeller size. Conclusions The results of this study can provide references for the research and design of polar icebreakers and other diesel/battery hybrid electric ships.

Design and application of moonpool system in polar icebreaker Xuelong 2

Objective In polar regions, the operation mode of launching and recovering detection and sampling devices for scientific research by shipside is limited due to dense ice floes around ship. For achieving the smooth acquisition of data records and samples in the densely packed ice floes regions, a square shape moonpool system was designed in the mid-ship of Xuelong 2 icebreaker. Methods Benefiting from the accumulated experiences from the polar surveys for decades, and taking into full account of operation characteristics in the ice zone, the design option of reasonable setting of switching process between shipside and moonpool operation was put forward. Specifically, innovative use of techniques such as water-tight bottom cover of moon pool, special track docking plan, de-icing of movable joints in low temperature environment was implemented. Result The field tests in Antarctic area demonstrated that the proposed scheme can effectively deal with the problem of launching and recovering of apparatus and devices for scientific survey in the densely packed ice floe region. Conclusions The proposed moonpool scheme fullfil the actual need of Chinese polar expedition, thereby increased the sampling capability of Xuelong 2 in the densely packed ice floes regions and match the capacity of icebreaking of the ship.

Ice-breaking performance sensitivity of the polar icebreaker to structure, control and ice parameters under different prediction models

Ice-breaking processes of an icebreaker are complex and many numerical models are proposed to predict the ice-breaking performance. Under the same polar conditions, different prediction models may derive different ice-breaking performances. Hence, it is necessary to analyze the influences of different prediction models and their corresponding input factors on the ice-breaking performance. However, there is almost no relevant study on such issues and it is urgent to fill this gap. In this study, different prediction models of the ice resistance are compared and analyzed. Subsequently, a global sensitivity analysis (SA) of the ice-breaking performance is performed for key input factors including structure, control, and ice parameters. Results show that the same input factors have appreciably different influences on the ice-breaking performance between different models. Besides, a global sensitivity of the maximized ice-breaking performance to structure parameters is analyzed, finding that the ship width is the most decisive factor. Impacts of different prediction models on the maximized ice-breaking performance regarding control parameters are also studied. Results indicate that model selection greatly influences the optimal performance and controls. Finally, an SA-based design process for the icebreaker is established, which can help perform the design work in a relatively efficient and economical way.

Experimental study on low temperature fatigue performance of polar icebreaking ship steel

The low-temperature mechanical properties and low-temperature fatigue properties of polar icebreakers steel are the key to ensure the safe operation of polar icebreakers under low temperature conditions. The main material of the polar icebreaker “Snow DragonⅠ” is EH36 steel due to its good impact toughness and low temperature resistance. In this paper, the tensile experiments and fatigue behavior of EH36 steel used in “Snow Dragon” under different temperatures are studied. The mechanical properties and low-temperature fatigue crack growth characteristics of the material were obtained. The experimental results show that the yield strength, tensile limit, elongation, and cross-sectional shrinkage will increase to varying degrees with decreasing temperature. As the temperature decreases, the plasticity of EH36 steel decreases and the brittleness increases. The fatigue crack growth rate of EH36 steel is lower at low temperature than normal room temperature. The fatigue crack growth threshold at low temperatures is higher than the room temperature threshold. Good resistance to crack initiation and crack growth of EH36 steel at low temperature are verified by the experiments.

A stochastic method for the prediction of icebreaker bow extreme stresses

It is well established that the ship-ice interaction process is quite complex and associated ice loads on the icebreaker hull is a stochastic process. Obviously, novel accurate statistical methods and models should be developed and applied to estimate extreme bow stresses.This paper studies icebreaker bow stresses based on measured distribution of ice thickness in the Arctic Ocean on the way to and from the North Pole. Since the vessel route was carefully selected searching for easier ice conditions, the Arctic Ocean crossing was not a straight linear but a meandering path. Thus, the specific ship route data was biased with respect to general ice statistics in the region, but true with respect to the route specific ice data encountered by a ship navigating in that region. Therefore the route specific ice thickness data is directly needed for ship design and navigation analysis. It is assumed that captains are competent and knowledgeable, and therefore will select a route that provides the most favourable ice conditions.This paper contributes to study of the newest Chinese self-designed polar icebreaker, serving the purpose of enhancing icebreaker operational reliability. Finite Element Method software package ANSYS/LS-DYNA has been employed to simulate bow stress pattern for a particular icebreaker operating in the Arctic Ocean. Extreme bow stresses were estimated using Naess-Gaidai method. The latter is a first application of Naess-Gaidai method to a distribution with lower bound. Thus this paper aims at introducing an efficient method of estimating route-specific icebreaker extreme bow stresses.

The effects of unsteady change in wind direction on the airflow over the helicopter platform of a polar icebreaker

The effects of the unsteady change of the wind direction on the airwake over the helicopter platform of a Canadian Coast Guard polar icebreaker were studied experimentally. By application of particle image velocimetry on a scaled model of the icebreaker, quantitative flow field data were obtained for several rates of change in the wind direction. This study was conducted in a water channel that featured a simulated atmospheric boundary layer as inflow condition. The rate of change in the incidence angle, α˙, varied in the range −0.25 ≤ α˙L/U ≤ 0.25, where L and U are the characteristic length and velocity, respectively. In addition to the time-averaged velocity fields, the turbulence intensity was evaluated to investigate the unsteadiness of the flow. Increasing the rate of change of the incidence angle of the incoming flow resulted in an increase of the turbulent intensity for all considered nominal incidence angles of the inflow. A notable exception to this trend was observed at α = 60°, where the direction of the inflow change had a pronounced effect on the structure of the flow over the helicopter deck. Thus, negative values of α˙L/U resulted in the wake of the superstructure not affecting the flow over the helicopter platform.

Experimental investigation of airflow over the helicopter platform of a polar icebreaker

The airwake over the helicopter platform of a Canadian Coast Guard (CCG) polar icebreaker was studied experimentally. By application of high-speed particle image velocimetry (PIV) on a 1:522 scaled model of the polar icebreaker, quantitative flow field data were obtained in several vertical and horizontal planes. The investigation compared the effects of two types of inflow conditions: (i) a uniform flow and (ii) a simulated atmospheric boundary layer (ABL) on the flow structure over the helicopter platform of the ship. The incidence angle (α) between the oncoming flow and the orientation of the ship varied between 0° and 330° with the increment of 30°. The unsteadiness of the flow and the turbulent fluctuations were quantified by calculating the components of the Reynolds stress tensor and the turbulence intensity. Higher maximum values of the turbulence intensity were observed in the case of the simulated ABL. For both inflow conditions, the incidence angle of 300° corresponded to the highest turbulence levels over the helicopter platform.

The Coast Guard Advances its Arctic Readiness in 2015, But Challenges Remain

In 2015, as the United States assumed its two-year chairmanship of the Arctic Council, the U.S. Coast Guard planned and executed a number of initiatives to advance maritime safety, security, and stewardship mission readiness in the Arctic. Yet the failure of Congress to provide the level of support necessary for the Coast Guard to adequately recapitalize its small and aging polar icebreaker fleet casts doubt on the service’s ability to fully meet its mandate to provide year-round, assured access and self-rescue in the polar regions. Hopefully, that trend will be reversed in the coming years.

Research of the Optimal Propulsion System for a Polar Scientific Icebreaker

It’s very impending for our country and scientists to build a new polar scientific icebreaker in order to take the place of the scientific icebreaker “Snow Dragon”, which is not suitable for more and more scientific researches in the polar areas in future, because many latest technologies and equipments, which improve icebreaker performances and research abilities, have appeared in recent years. To ensure icebreakers break ice and sail normally in atrocious polar environment, propulsion systems must be analyzed and designed particularly. According to the relative classification rules, many propulsion systems for a new polar scientific icebreaker are analyzed and compared with each other carefully in the process of project designs. And with a view to the vessel specification and work assignments in the polar areas, Azipod units are selected as the optimal propulsion systems for the icebreaker at last.

European countries have designs on planned polar research icebreaker Aurora Borealis

European countries have designs on planned polar research icebreaker Aurora Borealis

USCGC Healy (WAGB 20)—A Case Study for Implementing Reliability-Centered Maintenance

In new ship construction, maintenance planning affords both an opportunity and a challenge. On one hand, a new ship class enables maintenance planners to start with a clean slate and consider improved and more cost-effective maintenance methods. On the other hand, new manning concepts, lack of timely technical information when maintenance planning is conducted in parallel with detail design, use of equipment new to the fleet, and the like impose a measure of uncertainty on the planning process. In this paper, we review why and how Reliability-Centered Maintenance (RCM) techniques were applied to the new Polar icebreaker U.S. Coast Guard Cutter (CGC) Healy (frontispiece). We review how we incorporated condition-based maintenance techniques where appropriate. We discuss the decision process used for fine-tuning the Maintenance Procedure Cards (MPC) for CGC Healy's hull, mechanical, and electrical (HM&E) Preventive Maintenance Manual. Finally, we share some lessons learned in the process.

Optimized Alignment of a USCG Polar Class Icebreaker Wing Shaft Using a Distributed Bearing Finite-Element Model

There are indications that new analytical techniques must be employed for determining and optimizing the shaft alignment of the wing shafts of the U.S. Coast Guard's Polar Class icebreakers. These indications include failing shaft coupling bolts and excessive stress concentration factors in the shaft. Current design practices dictate the use of point bearing loads for both design and realignment analysis of propulsion shafts. In this work, a general purpose finite-element code is utilized for modeling the shaft. The bearings are modeled as flexible distributed supports. A public domain optimization routine is coupled to the analysis for determining the optimum shaft alignment. The new process is validated, and then utilized for analyzing the USCG Polar Class ice-breaker wing shafts. Results are presented and discussed.

Using Simulation to Determine the Maneuvering Performance of the WAGB‐20

ABSTRACT The WAGB‐20 is a U. S. Coast Guard polar icebreaker with an integrated diesel‐electric propulsion system. Power is generated by four main diesel engines driving AC generators. Two main 15,000‐HP AC synchronous propulsion motors are directly coupled to the port and starboard propellers. Two cycloconverters provide variable‐voltage, variable‐frequency power for controlling each propulsion motor.The simulation of the electric propulsion system is being developed to analyze the steady‐ state and transient performance of the system during open water and icebreaking operations. The objectives of the analysis are to support propulsion plant design, aid in the integration of system components, develop control system algorithms, predict system performance, and determine the requirements for dynamic braking resistors.The analysis consists of mathematical models for the ship, shaft systems, propellers, AC synchronous propulsion motors, motor controllers, cycloconverters, generators, generator exciters, voltage regulators, diesel engines, and engine governors. These models are based on actual machinery data.The WAGB‐20 specification requires the propulsion system to have the capability of going from full power ahead to full power astern in open water in 25 seconds or less. This paper presents the simulation results which show that by controlling the regenerative power the crash astern maneuver can be performed to meet this requirement without the need for dynamic braking resistors.

Breaking the Ice of Acquisition Reform

ABSTRACT In the spring of 1992 the Naval Sea Systems Command was forced to cancel the solicitation for the Coast Guard Polar Icebreaker replacement due to affordability issues. Yet less than a year later a contract was awarded for detailed design and construction of a Polar Icebreaker. To accomplish this, a team was organized in April of 1992 to rethink the technical and programmatic approach for acquisition. A number of the approaches used have been included in the new Department of Defense (DoD) acquisition policy statement of June 1994.Because of the innovative nature of the approach, the Program Office conducted a lessons learned review by revisiting program documentation and interviewing the major players. This paper examines the process through which changes were made and the rationale for them. It finishes with a summary of some of the more important lessons learned by the project team both during the redevelopment of the solicitation and the first phase of the contract.

Firesafety Analysis of the Polar Icebreaker Replacement Design

Fire safety aboard Coast Guard cutters is an important part of their design. In 1987, a pro ject was completed that involved a developmental application of the Ship Fire Safety Engineering Methodology (SFSEM) to the firesafety analysis of the Polar Icebreaker Replacement (PIR) design. The passive and active fire protection was analyzed for every compartment on the PIR in the integrated framework provided by SFSEM. Conventional fire protection engineering was used whenever information necessary for SFSEM was not avail able. Recommendations for alternative solutions to accomplish performance-based fire safety objectives, as well as guidelines for selected fire protection systems on the PIR, were provided.This paper describes the framework for the firesafety evaluation, techniques for quantifica tion, and the advantages and limitations identified by this application of the SFSEM for ship firesafety design. The quantification integrated available statistical data with case study analysis, inspection of the op...

U.S. polar icebreakers

An interagency study of the nation's polar ice‐breaking requirements through the end of the century was recently completed. The Polar Icebreaker Requirements Study (PIRS) Group presented fleet size alternatives and recommended that the Icebreaker User Council define the capabilities required for new icebreakers. The User Council consists of representatives from the U.S. Navy, National Science Foundation, the Maritime Administration, and the U.S. Coast Guard.Polar icebreakers are needed for three basic purposes: (1) resupply of Antarctic and Greenland stations, (2) logistical support of polar operations, and (3) scientific research. One of the PIRS recommendations was that any new icebreaker designs should enhance science support while meeting the requirements for escort and logistics. The U.S. Coast Guard will soon begin the preliminary design for a new class of polar icebreakers.

Some Considerations in the Design of Polar Icebreakers

This paper highlights some primary considerations in the design of polar icebreakers. Factors affecting determination of power-displacement relationships and the propulsion horsepower are discussed, as is the importance of clearly defining the manner in which the various ice conditions are to be handled. The authors deal briefly with hull construction aspects, outlining the general requirements for polar-class icebreakers, choice of parameters, and the principal hull design features of a proposed new Canadian polar icebreaker. Propulsion machinery options are discussed, including medium-speed diesel engines, aircraft and industrlal-type gas turbines, and combination systems.

Design Considerations for Shipboard Vibration

Shipboard vibration continues to present serious problems to both the shipbuilder and operator. The principal reasons for this deficiency is the lack of a design procedure, useful in the early phases of design, and the absence of a suitable criterion for hull vibration. This paper describes a detailed study carried out for the U.S. Coast Guard for a "new design polar icebreaker" and a procedure for further simplification of this approach presently under development at the Naval Ship Research and Development Center (NSRDC). Procedures for the measurement and evaluation of shipboard vibration are briefly discussed together with possible approaches to the development of suitable shipboard vibration criteria.

MODEL TESTING IN ICE

Naval Engineers JournalVolume 80, Issue 2 p. 259-264 MODEL TESTING IN ICE LIEUTENANT COMMANDER G. P. VANCE, LIEUTENANT COMMANDER G. P. VANCE USCG THE AUTHOR: was graduaed from the U. S. Coast Guard Academy in June 1957 with a Bachelor of Science Degree and an Ensign's Commisison in the U. S. Coast Guard. His first assignment was a weather patrol ship operating in the North Atlantic. He first served as a deck officer; later as an engineering watch officer. The period from 1960 to 1961 was spent as Commanding Officer of Ulithi Loran Station in the South Pacific. The period from 1961 to 1963 was spent at the University of Michigan in pursuit of a Master of Science Degree in Naval Architecture, Marine Engineering and Nuclear Engineering. Upon graduation from Michigan, LCDR Vance served as engineering officer aboard the Coast Guard icebreaker WESTWIND until 1965, when he was transferred to Coast Guard Headquarters to work on the design of a new Coast Guard polar icebreaker. LCDR Vance is a member of the American Society of Naval Engineers and a Registered Professional Engineer in the state of Michigan.Search for more papers by this author LIEUTENANT COMMANDER G. P. VANCE, LIEUTENANT COMMANDER G. P. VANCE USCG THE AUTHOR: was graduaed from the U. S. Coast Guard Academy in June 1957 with a Bachelor of Science Degree and an Ensign's Commisison in the U. S. Coast Guard. His first assignment was a weather patrol ship operating in the North Atlantic. He first served as a deck officer; later as an engineering watch officer. The period from 1960 to 1961 was spent as Commanding Officer of Ulithi Loran Station in the South Pacific. The period from 1961 to 1963 was spent at the University of Michigan in pursuit of a Master of Science Degree in Naval Architecture, Marine Engineering and Nuclear Engineering. Upon graduation from Michigan, LCDR Vance served as engineering officer aboard the Coast Guard icebreaker WESTWIND until 1965, when he was transferred to Coast Guard Headquarters to work on the design of a new Coast Guard polar icebreaker. LCDR Vance is a member of the American Society of Naval Engineers and a Registered Professional Engineer in the state of Michigan.Search for more papers by this author First published: April 1968 https://doi.org/10.1111/j.1559-3584.1968.tb04509.xCitations: 2 AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume80, Issue2April 1968Pages 259-264 RelatedInformation