﻿ 船体板架纵骨错位对焊接变形及应力的影响
 舰船科学技术  2023, Vol. 45 Issue (22): 18-24    DOI: 10.3404/j.issn.1672-7649.2023.22.004 PDF

Effect of longitudinal dislocation on welding deformation and stress
HUANG Jia-le, CHEN Zhen
State Key Laboratory of Ocean Engineering, Shanghai Jiaotong University, Shanghai 200240, China
Abstract: In the welding process of hull grillage, dislocation of the longitudinal stiffener caused by the manufacturing errors has a negative iMPact on welding process and welding quality. To deal with the problem, the present paper proposes an analytical approach for welding hull grillage with dislocated longitudinal stiffener based on thermal elastic-plastic finite element method. A typical hull grillage is taken as an example to investigate the dislocation influence on the welding distortion and residual stress considering the effect of forced alignment. It is found that the asymmetry of panel distortion on both sides of the dislocated stiffener becomes obvious gradually as the dislocation degree increases. In other words, panel distortion close to the side of the dislocated stiffener is aggravated, while that away from the other side is reduced, the deformation difference between the two sides can be increased by 3.7 times at most. When the dislocation is constant, the influence of longitudinal dislocation increases with the decrease of plate thickness. In addition, stress is increased when the dislocation degree is developed, and when the dislocation is 10mm, the residual tensile stress and compressive stress are 4.4 and 4.9 times higher than that of the longitudinal without dislocation.
Key words: longitudinal dislocation     hull grillage     welding distortion     residual stress
0 引　言

1 概　述

 图 1 船体板架纵骨错位示意图 Fig. 1 Longitudinal dislocation of hull grillage
2 分析模型 2.1 研究对象

 图 2 船体板架几何尺寸 Fig. 2 Geometry of hull grillage
2.2 有限元模型

 图 3 有限元模型 Fig. 3 Finite element model
2.3 焊接顺序及边界条件

 图 4 焊接顺序及边界条件 Fig. 4 Welding sequence and boundary conditions

2.4 热源模型与材料属性

 图 5 双椭球热源模型 Fig. 5 Double ellipsoid heat source model

 ${q}_{f}(x,y,z)=\frac{6\sqrt{3}({f}_{f}Q)}{{a}_{f}bc {\text{π}} \sqrt{{\text{π}} }}\mathrm{exp}\left(-\frac{3{x}^{2}}{{a}_{f}{}^{2}}-\frac{3{y}^{2}}{{b}^{2}}-\frac{3{z}^{2}}{{c}^{2}}\right)，x > 0 。$

 ${q}_{r}(x,y,z)=\frac{6\sqrt{3}({f}_{r}Q)}{{a}_{r}bc{\text{π}} \sqrt{{\text{π}} }}\mathrm{exp}\left(-\frac{3{x}^{2}}{{a}_{r}{}^{2}}-\frac{3{y}^{2}}{{b}^{2}}-\frac{3{z}^{2}}{{c}^{2}}\right)，x\leqslant0。$

 图 6 材料属性 Fig. 6 Material properties
3 计算方法

 图 7 计算流程图 Fig. 7 Flowchart of analysis

4 数值模拟结果与分析 4.1 温度场结果

 图 8 瞬态温度分布及热循环曲线 Fig. 8 Transient temperature distribution and thermal cycle curve
4.2 焊接变形

 图 9 整体结构垂向变形云图 Fig. 9 Overall vertical deflection

 图 10 S区域焊接变形图 Fig. 10 Welding deformation in S region

 图 11 A、B区域三维变形图 Fig. 11 3D deformation of regions A and B

 图 12 直线位置 Fig. 12 Position of lines

 图 13 Line1处焊接垂向变形 Fig. 13 Deflection on line1

 图 14 Line2和Line3处焊接垂向变形 Fig. 14 Deflection on line2 and line3

 图 15 各板厚下Line1处垂向变形 Fig. 15 Deflection at Line1 under each plate thickness

4.3 应力场结果

 图 16 强制装配产生的应力 Fig. 16 Stresses due to forced assembly

 图 17 焊后残余应力 Fig. 17 Residual stress after welding
5 结　语

1）纵骨错位现象使得该纵骨两侧板格的焊后变形分布不一致，随着错位量的增加，两侧板格焊后变形差异愈加明显，最大可相差5.3倍。

2）错位纵骨左右两侧板格的焊接变形与纵骨错位量的关系呈相反变化趋势，其中左侧板格的焊接变形与错位量呈正比。纵骨错位10 mm与纵骨未错位相比，左右两侧板格变形差值增加3.7倍。

3）当错位量一定时，外板厚度越小，纵骨错位对船体板架焊接变形的影响越大。

4）随着错位量的增加，焊接初始应力与焊接残余应力均增加。初始拉应力与压应力最大可达到294.8 MPa和 234.1 MPa；对于焊接残余应力而言，当错位量为10 mm时，最大拉应力与压应力分别是纵骨未错位的4.4倍与4.9倍。

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