﻿ 船体加筋板结构焊接变形和残余应力热弹塑性有限元分析
 舰船科学技术  2016, Vol. 38 Issue (6): 47-51, 80 PDF

Thermal elastic-plastic FEM analysis of welding deformation and residual stress of a stiffened plate structure in hull
YU Qi, CHEN Zhen
School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiaotong University, Shanghai 200240, China
Abstract: In order to improve the efficiency of thermal elastic plastic finite element method (TEP FEM), the static substructure method is adopted to fulfill heat transfer analysis of welding process. The overall stiffened plate structure is divided into several uniform static substructures according to its repeatability and symmetry. Heat transfer analysis of one substructure welding is implemented by means of TEP FEM and then the temperature fields of other substructure welding are obtained via mirroring and translation from the calculated results. The static substructure method is applied to the welding simulation of a stiffened plate structure in hull and good agreements of thermal and mechanical results are obtained. The efficiency of the proposed approach is proved extremely high compared with the existed method.
Key words: welding simulation     static substructure     temperature field mapping     stiffened plate structure     welding distortion
0 引言

1 问题的提出

 图 1 船体加筋板几何尺寸 Fig. 1 Geometry of stiffened panel

2 静态子结构方法与温度场映射 2.1 静态子结构

 图 2 子结构和温度场映射 Fig. 2 Substructures and temperature mapping
2.2 温度场映射

3 有限元数值模拟

 图 3 计算流程图 Fig. 3 Flowchart of analysis

 图 4 计算有限元模型 Fig. 4 FE model

 图 5 材料属性 Fig. 5 Material properties

 $q = \frac{{3Q}}{{\pi {r_a}^2}}\exp \left\{ {\frac{{ - 3{r^2}}}{{{r_a}^2}}} \right\}\text{。}$ (1)

4 计算结果分析与讨论 4.1 静态子结构与完整结构计算对比

 图 6 子结构边缘温度与完整结构温度对比图 Fig. 6 Temperature comparison between the edge of SS1 and overall structure

 图 7 点 A 的温度历程曲线 Fig. 7 Temperature history of point A

4.2 全结构焊接变形

 图 8 船体加筋板整体变形云图 Fig. 8 Overall vertical deflection

 图 9 纵横路径的位置示意图 Fig. 9 Location of L1~T3

 图 10 结构的面外变形 Fig. 10 Vertical distortion
4.3 残余应力

 图 11 水平板中面在 T2 处的纵向残余应力 Fig. 11 Longitudinal residual stress at middle surface of plate at T2

 图 12 水平板上表面 T2 处的横向残余应力分布图 Fig. 12 Transverse residual stress at middle surface of plate at T2
5 结语

1）通过静态子结构方法有效地降低了热传导分析的自由度，实现焊接数值模拟中热传导分析，并将其应用于船体多筋加筋板的焊接残余变形和应力的预报，在保证计算精度的同时，大幅度提高了计算效率。因此该方法可以应用于船体某些大型板架的焊接数值模拟。

2）船体板架的焊接会引起纵横 2 个方向的收缩，使结构产生双向弯曲，焊接顺序不对称还会引起板架的整体扭曲变形。

3）船体加筋板在焊缝附近，焊接纵向残余拉应力大小约为材料屈服极限，在远离焊缝区域残余应力迅速降低并转变为均匀分布的压应力。在焊接结束后，加筋板的水平板中横向残余应力基本呈对称分布，焊接顺序对板架的残余应力分布并无明显的影响效应。

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