【作者】 魏欣伟；

【导师】 郑振太；

【作者基本信息】 河北工业大学 ， 材料加工工程， 2007， 硕士

【摘要】 火焰成形加工工艺已成为造船生产流程的瓶颈,从而引起了人们的关注。近年来,国内外对船体复杂曲面钢板自动火焰成形的课题都进行了大量的研究,目的就是为了实现该加工过程的自动化。本文的工作就是基于这样的背景开展起来的。通过对国内外研究工作的分析可以看出,火焰成形研究的关键问题是火焰成形加工中以特征参数表示的温度场规律及变形场规律,而研究的核心则是通过理论计算、数值模拟、实验或总结经验等方法来得到温度场特征参数与变形影响参数间的关系。分析了包括热源模型、单加热线下的温度模型及变形场模型在内的整个火焰成形过程的数学模型。热源模型主要介绍了氧乙炔焰冲击射流对流换热的基本方程、边界条件,热流密度的半解析解、经验公式及高斯分布的热流密度模型。温度场模型讨论了单加热线条件下的移动热源温度场问题的基本方程和边界条件。变形场模型则分析了线移动热源作用下板的三维瞬态热弹塑性变形的数学模型。这些模型是火焰成形温度场及变形场计算和分析的理论基础。在上述数学模型的基础上,分析了火焰成形过程的温度场,在材料的热物性和边界换热条件随温度变化的情况下,用有限元法进行了三维瞬态温度场的数值分析,得出了加工过程中任意时刻钢板内的温度分布。并根据有限元计算及实验结果,提出了火焰成形温度场的特征参数。在分析了火焰成形温度场分布规律的基础上,建立了火焰成形变形场的有限元计算模型。然后根据不同加工参数下的有限元计算结果,对火焰成形的温度场及变形场作了初步分析,讨论了残余位移及残余应变在整块板上的分布特性。为了验证上述有限元计算模型的可靠性,建立了一套火焰成形的实验装置。并根据拟定的实验步骤,验证了火焰成形温度场和变形场有限元计算的可靠性。通过这些实验验证,可以认为上述火焰成形的有限元计算模型是可靠的,可以用来分析火焰成形温度场与变形场的基本规律。更多还原

【Abstract】 The whole ship industry is paying attention to the research of line heating forming because the technique has been being the bottleneck of the whole shipbuilding system in recent years. As a result, many attempts have been trying to analyze the line heating process theoretically and experimentally and making it an automatic process is the goal of the research. The paper is developed under this background.By analysis of researches both in home and abroad, it was considered that the key problem of study on line heating was the temperature field rules based on characteristic parameters and deformation field rules based on global deformation description method, and the centric study is obtain relation between temperature field characteristic parameters and deformation field affecting parameters analytically, numerically, experimentally, or experientially. In detail, four aspects were studies in this paper:The full mathematics model of line heating, including heat source model, temperature field model under single heating line and deformation field model was established. As for heat source model, the basic equation, boundary conditions, semi-analytical solution, empirical formula, and Gauss distribution heat flux model were discussed. For temperature field model, the basic equation and boundary conditions of temperature field under moving heat source were discussed. And for deformation field model, the mathematics model of 3D transient thermo elastic-plastic deformation of plate under moving heat source along line was established. These models are ground of the numerical simulation and analysis of temperature field and deformation field of line heating.Based on above mathematics model, the temperature distribution in the plate during the Line-heating procedure is analyzed, and the numerical analysis of the transient temperature distribution of a three dimension under the condition that the thermo-material property and the heat exchanging condition on the boundary vary with temperature is completed.According to FEM results, temperature field characteristic parameters were presented. Ground on above rules of temperature field of line heating, the FEM model of deformation field of line heating was setup. And a preliminary analysis of to field and deformation field was carried out, and the distribution of the residual displacement and strain on the whole pate was discussed.To verify the validity of above FEM model, a set of experiment equipments and procedure w ere setup. Then the reliability of FEM model of line heating was verified. The experiments verified the validity of above FEM model, and the rules of temperature and deformation field can be analyzed both experimentally and numerically.更多还原