Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

A Study of the Double-Side Induction Line Heating for Shipbuilding
aLichun Chang a, Yao Zhao a,b,c, Hua Yuan a,b,c
School of Naval Architecture and Ocean Engineering, Huazhong University of Science and Technology
Wuhan, Hubei, Chinab
Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE)
Shanghai, ChinacHubei Key Laboratory of Naval Architecture and Ocean Engineering Hydrodynamics
Wuhan, Hubei, China
using a simplified surface heat source is proposed. The results of thesimplified calculation and the fully coupled calculation are compared,
and it is concluded that the simplified calculation can improve thecalculation efficiency while maintaining the calculation accuracy. Dong(2018) investigates the width of induction coils in line heatingprocessing and concludes that a larger induction coil can improve theprocessing efficiency. Zhao (2017) proposed to combine line

ABSTRACTThe double-curved plates forming is an important task in shipbuilding,and the line heating plate forming method is the traditional complex
curved plate forming process. This paper proposes the double-sided
electromagnetic induction line heating process used in plate forming.
By using this process, the in-plane shrinkage deformation is decoupledfrom the bending deformation. Using the thermo-elastic-plastic finite
element method, we study the characteristics of the double-sided
heating processing under the conditions of different process parametersand different initial curvatures.

heating and roller bending for surface processing. By combining
different machining tools with each other, a richer deformation
can be produced.

KEY WORDS: Line heating; double-side heating; plastic strain;
plate forming; finite element analysis.
INTRODUCTION
The curved surface plates forming is an important work in shipbuilding,and the line heating process is the traditional process of plate forming
and processing complex curved surfaces with bidirectional curvature.
With the development of manufacturing technology in shipbuilding, theelectromagnetic induction line heating method is widely used inshipyards. In the line heating process, various deformations such astransverse bending, transverse shrinkage, longitudinal bending, andlongitudinal shrinkage are usually produced.
There have been many published studies on the processing of line
heating. Ueda (1994) studied the characteristics of line heatingprocessing, gave the application of line heating process is actually
curved plate forming, and proposed to use the inherent deformation todescribe the processing. Vega (2008) studied the mutual influence
between different heating lines when they are superimposed on eachother, and gave the deformation influence regularity when the paths
are superimposed. Lee (2013) investigated the line heating-induced
permanent deformation behavior of thick plate through both numericalanalysis and experimental testing by applying high-frequency induction
heating. Zhu (2018 and 2019) proposed to use electromagnetic thermal
full coupling finite element method to simulate the electromagnetic
induction line heating process, and a simplified calculation method

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This paper proposes a new processing method using double-sided
induction line heating, through which the in-plane shrinkage
deformation can be increased and the bending deformation can bereduced, making the in-plane shrinkage deformation decoupled fromthe bending deformation to a certain extent. In this paper, the doublesided induction heating process is investigated employing thermoelastic
finite element calculation.

NUMERICAL ANALYSESIn this paper, the electromagnetic induction line heating process with adouble-sided heat source in the shipbuilding process is studied. Acircular coil is selected as the heat source with an outer diameter of 100mm and an inner diameter of 60 mm, and the frequency of induction
heating is 12.7 kHz. Firstly, the heat source model of the heating coil isestablished by using electromagnetic field finite element analysis, andthe heat source is simplified to a surface heat flow density by referring
to Zhu (2019) and Dong's (2019) method. A square steel plate of1m  1m  20mm is used for simulation calculations, and a line heatingprocess is performed in the center of the plate along the x-direction. As
shown in Fig. 1.
ABAQUS software is used to calculate the temperature and stress fields
during the line heating process. A 1m  1m  20mm square steel plate isused for the simulation. The grid is set to 10mm  10mm with 10,201
nodes and 10,000 elements, shown in Fig. 2. A four-node reduced
integral shell element (S4R) is used in the deformation calculation, anda four-node heat transfer element (DS4) is used in the heat transfer