﻿ 钛合金耐压球壳极限强度数值估算方法
 舰船科学技术  2019, Vol. 41 Issue (4): 49-53 PDF

1. 山东交通学院威海校区，山东 威海 264200;
2. 中国船舶重工集团有限公司，北京 100097;
3. 哈尔滨工业大学（威海）船舶与海洋工程学院，山东 威海 264209

Research on the numerical method on the ultimate strength of titanium alloy pressure spherical shell
ZHANG Xi-qiu1, YU Hao2, YU Chang-li3, YANG Shuo3
1. Shandong Jiaotong University Weihai Campus, Weihai 264200, China;
2. China Shipbuilding Industry Corporation Co., Ltd., Beijing 100097, China;
3. Harbin Institute of Technology (Weihai), School of Naval Architecture and Ocean Engineering, Weihai 264209, China
Abstract: Deep Sea Vehicle (DSV) is indispensable to marine development, and the pressure spherical shell, the structure design of which is key to general performance and weight index of DSV, forms the heart of equipment and personnel safety. The welding process has an assignable impact on the ultimate strength of the pressure shell. Therefore, in this paper, a numerical method considering the welding process is presented, which takes the material property change, the residual stress as well as the deformation induced by welding into account. Firstly, welding numerical simulation is carried on based on Gaussian heat source. Secondly, the material affected by welding is distinguished as equivalent property and equivalent zone. Finally, the ultimate strength of the pressure shell is worked out by numerical method. Comparison with previous experiment as well as numerical simulation shows that the numerical results proposed in this study are slightly lower, that’s because the welding process is not completely considered in the literature. Thus the numerical method in the present study allows for the safety margin, it has high engineering value.
Key words: titanium alloy     pressure spherical shell     ultimate strength     numerical method
0 引　言

 图 1 耐压球壳材料属性区划分 Fig. 1 Material properties distinction scheme of pressure spherical shell
1 数值计算模型

 图 2 随温度变化的材料热动力属性 Fig. 2 The Change of material thermodynamic properties with temperature

 图 3 网格划分方案 Fig. 3 Scheme of meshing

 ${w_i} = \frac{{0.01 \cdot t}}{{{2^{i - 1}}}}\text{。}$ (1)

2 钛合金球壳焊接数值模拟

 $\begin{split} {{q}_{r}}= &\frac{6\sqrt{3}Q}{{}^{{{{\text{π}} }^{3}}}\!\!\diagup\!\!{}_{2abc}\;}\exp \left(-3\left( {{\left( \frac{x}{a} \right)}^{2}}+ \right.\right. \\ & \left.\left. {{\left( \frac{y}{b} \right)}^{2}}+{{\left( \frac{z}{c} \right)}^{2}} \right) \right) {\text{。}} \end{split}$ (2)

 图 4 焊接初始阶段模拟结果 Fig. 4 Numerical result for welding inital stage

 图 5 焊接模拟过程结果 Fig. 5 Numerical result for welding process

 图 6 过程温度场 Fig. 6 Teperature distribution for welding process

 图 7 焊缝垂线位置温度变化曲线 Fig. 7 Temperature variation of position vertical welding track
3 基于焊接热影响区域划分的钛合金球壳极限强度评估

 图 9 耐压球壳极限强度时应力分布 Fig. 9 Stress distribution of pressure spherical shell inlimite state

 图 10 耐压球壳击溃时失效模式图 Fig. 10 Failure mode of collapse pressure spherical shell

 图 11 评估结果对比 Fig. 11 Comparison of assessment results with references

 $\begin{split} {{P}_{U}}= &-1.408\times {{10}^{5}}\times {{\left( {t}/{R}\; \right)}^{3}}+1.822\times {{10}^{4}}\times \\ & {{\left( {t}/{R}\; \right)}^{2}}+1.065\times {{10}^{3}}\times \left( {t}/{R}\; \right)-0.714\ 7 \text{。} \end{split}$ (3)

Matlab中和方差（SSE）与确定系数（R-square）可以很好地反应数据拟合的效果，其中SSE越接近0，R-square越接近1，说明拟合效果越好。式（3）拟合的SSE值足够小，仅为4.949，而R-Square值为0.999 8，足够接近1，证明式（3）充分反映了原始数据之间的关系。

4 结　语

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