火工矫正工艺数学模型及热弹塑性分析

【作者】 张爱霞；

【导师】 刘玉君； 纪卓尚；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2003， 硕士

【摘要】 在船舶建造和修理过程中，焊接变形是不可避免的。为矫正船体结构焊接变形，船厂一般利用人工操作进行火工矫正，从而造成生产效率低，劳动强度高，船体建造成本增加等问题。人工操作已经不能满足现代造船业及国际市场的需求；火工矫正工艺的信息化问题成为当前船体建造过程中迫切需要解决的重要课题之一。 本论文课题源于“大连造船厂国防预研项目×××舰945钢火工矫正方法研究”，结合火工矫正工艺的实际实验，就以下内容进行了研究： 1、火工矫正工艺的实验原理及测试方法 介绍了用火工矫正工艺减少焊接变形的原理；并结合实践说明火工矫正工艺的实验对象、实验参数、实验目的、测量仪器及实验步骤。 2、火工矫正工艺数学模型的研究 通过建立数学模型，描述火工矫正变形量与火工矫正工艺参数，如加热时间及加热线长度之间的关系，并通过对回归模型的检验分析，证明所建立的数学模型可以部分地应用在生产中。 3、火工矫正温度场的数值分析 用有限元法进行三维瞬态温度场的数值分析，得出了火工矫正过程中任意时刻结构内的瞬态温度分布，并分析其温度场特征。 4、焊接残余应力及变形的数值分析 分析焊接残余应力及残余变形产生的根源；并以典型结构为例，求解其焊接残余应力及变形。 5、火工矫正工艺热弹塑性研究 通过对火工矫正过程进行非线性数值模拟，得出加热过程中任意时刻结构的应力场、应变场和位移场，以及最终的残余应力和残余变形；并对板厚及加热速度对残余应力及变形的影响作了分析。 通过以上研究，本文揭示了火工矫正工艺的本质规律。更多还原

【Abstract】 It is well known that weld distortion often occurs unavoidably in sectional hull building. One effective way that most shipyards prefer to use to correct distortion is flame correction. Up to now, this kind of process usually depends on the experience of skilled workers and, as a result, brings about such problems as low efficiency and high costs. On the other hand, the increasing competition over the last few years in the shipbuilding industry has forced shipyards to increase productivity and decrease costs. So the interest in shipbuilding automation, especially in the technology of correcting deformation by flame has increased enormously in recent years. In this paper, the following subjects are discussed:1 This paper introduces the principles and methods of technology of deformation correction by flame, and also sample pieces, parameters in the process, experimental purpose, etc.2 The paper sets up mathematical models which reflect the influence of two parameters such as heating time and length of heating line on this kind of technology; and proves that the models built can be used in practical production.3 The temperature field of the typical plate structure during the process of deformation correction by flame is analyzed, and the numerical analysis of the transient three-dimensional temperature field is completed.4 The factors that cause welding residual stresses are analyzed; and the residual stresses and deformation of typical plate structure are obtained.5 A general finite element program is used to simulate the three dimensional thermo-elastic-plastic process of the technology. By calculation, the results such as stresses, strains and displacements of the plate structure at any time during process of deformation correction are obtained.更多还原