中频感应加热消除薄板焊接失稳变形的机理研究

在“轻量化造船”中，焊接产生的固有变形使得高强钢薄板制造的船体加筋板发生失稳；而伴随焊枪移动的中频感应加热，可有效地消除焊接失稳变形。通过感应加热温度场的模拟，以及感应加热和焊接加热温度场的耦合分析，得出感应加热对整体温度场分布的影响机理。通过对不同感应加热和焊接加热下整体温度场平均温度的测量和计算，建立感应加热和平均温度关系的数学模型，阐明感应加热时，整体温度场变化的现象本质。通过焊接变形的测量和有限元分析，估算感应加热作用下的焊接固有变形，初步揭示感应加热消除焊接失稳变形的内在机理。三根棒力学模型分析感应加热时的焊接过程，结合固有应变的产生机理，解释侧棒温度因感应加热升高时，主棒固有应变减小的内在机制。本项目以固有变形为依据，阐明了感应加热作用时，焊接失稳变形消除的内在机理；为高质高效的船体加筋板制造工艺的制定，提供理论依据；对提升我国高新船舶制造的市场竞争力具有重要意义。

In production of lightweight ship structures, inherent deformation generated by welding will make stiffened ship panel buckle, which is fabricated with thin plates of high tensile strength steel; medium frequency induction heating moving with welding torch simultaneous, can effectively mitigate welding induced buckling. With modelling of temperature field generated by induction heating, and coupling analysis of temperature fields generated by induction heating and welding heating, the influence mechanism of induction heating on the whole distribution of temperature is obtained. Average temperatures of the whole temperature fields caused by different induction heating processes and identical welding heating are measured and calculated, to establish the mathematical model between induction heating and average temperature, and to clarify the nature of the phenomenon of whole temperature field changing with induction heating. By measurement and FE analysis of welding distortion, welding induced inherent deformations with induction heating processes are evaluated, to preliminarily reveal the intrinsic mechanism of the phenomenon that induction heating mitigates the welding induced buckling. Three-bar model is employed to examine the welding process with induction heating; with incorporating generation mechanism of inherent strain, the intrinsic mechanism of that inherent strain of main-bar decreases when temperature of side-bar elevates due to induction heating is clarified. This project which bases on inherent deformation, clarifies the intrinsic mechanism of mitigation of welding induced buckling with medium frequency induction heating; provides theoretical basis to constitute manufacturing specification with high productivity and quality of stiffened ship panel; has an essential meaning for our country to enhance the market competition of advanced ship fabrication.