大型船体结构焊接变形热弹塑性有限元数值模拟方法研究-船舶与海洋工程专业论文.docx

上海交通大学硕士学位论文 上海交通大学硕士学位论文 万方数据 万方数据 大型船体结构焊接变形热弹塑性有限元数值模拟方法研究 摘 要 热弹塑性有限元方法作为一种精度高、结构适应性强的焊接数值 模拟方法，被广泛应用于焊接接头和小型结构的焊接问题研究。但是 该方法计算耗时长、运算规模大，难以应用于大型复杂结构的焊接模 拟。本文针对焊接模拟热弹塑性有限元方法，提出了改进方法以提高 计算效率，并实现了大型船体加筋板结构的焊接过程模拟，本文所做 工作主要包括： (1)针对船体焊接中常见的 T 型接头形式，基于 ABAQUS 软件中 具有截面积分特性的 shell 单元配合 solid 单元提出了 shell/solid 模型 方法，有效的降低了建模复杂程度和求解自由度。通过对 T 型接头焊 接变形和残余应力计算对比，验证了采用 shell/solid 模型模拟结构焊 接过程的计算精度。 (2)提出了焊接模拟瞬时移动热源的简化等效方法，将瞬时移动热 源简化为分段移动热源：将焊缝划分为若干段，忽略各段内的热源移 动效应，沿焊缝方向依次施加各段的段状热流密度。通过 T 型接头算 例计算对比表明，通过合理划分分段数目，分段移动热源可以在保证 相近的计算精度下，有效的降低计算耗时。 (3)将 shell/solid 模型和分段移动热源应用于大型船体加筋板结构 的焊接过程模拟，计算了焊接变形和残余应力，通过与实测值比较， 验证了该方法的可行性和可靠性。 关键词：热弹塑性有限元方法，shell/solid 模型，分段移动热源，大 型船体结构，焊接变形与残余应力 I WELDING SIMULATION OF LARGE-SCALE HULL STRUCUTRE USING THERMAL ELASTIC-PLASTIC FE METHOD ABSTRACT Thermal elastic-plastic FE method(short for TEP) is widely used in the welding simulation of welding joint or small structures owing to its high accuracy and good adaptation. However, it is hard to realize the welding simulation of large scale structures using the method for its high computational costs. This thesis brings forward the shell elements model and segmented moving heat source used in TEP method for the purpose of enhancing computation efficiency of the approach. Also, welding simulation of a large scale stiffened structure of hull is realized by the improved TEP method and the accuracy is verified through comparing the calculation results and practical measured values of the structure. The main work in the thesis can be summarized as follow: By means of shell elements with section integration in ABAQUS code, a shell/solid model strategy is brought forward to improve the calculation efficiency of TEP method. A typical tee joint model is selected as an example to verify the precision of the new FE strategy. A segmented moving heat source is developed and employed in TEP method to replace the transient moving heat source. One welding line is divided into several segments. The materials of w