内高压成形机理与关键技术

在中国国家杰出青年科学基金资助项目“镁合金热态液力成形技术”、中国国家自然科学基金资助项目“轻体件高内压液力成形机理的研究”、“管材热态内压成形新方法及其机理研究”和“激光拼焊管内高压成形机理”、以及中国教育部高等学校博士学科点专项科研基金资助项目“镁合金热态内高压成形机理研究”共同资助下，开展内高压成形机理及关键技术研究，在内高压成形塑性变形规律、起皱和破裂等失稳行为、提高成形极限和降低成形压力方法，以及液力胀接、热态内压成形和拼焊管内高压成形等方面取得重要进展，并在汽车和航天等领域实现内高压成形技术产业化应用，报告上述研究的理论和工程体系。 根据塑性变形特点，将内高压成形分为变径管内高压成形(IHPF of TPVD)、弯曲轴线管内高压成形(IHPF of TPCA)和多通管内高压成形(IHPF of TPB/BT)等3类，提出IHPF of TPVD由充填、成形、整形等步骤组成，IHPF of TPCA由弯曲、预成形、内高压成形等步骤组成，IHPF of TPB/BT由胀形、补料、整形等步骤组成。以此为出发点，通过实验和理论分析，研究IHPF塑性变形规律与失稳行为。

Mechanism of Internal high Pressure Forming and its Key Technologies

Funded by Projects “Hydroforming of magnesium alloy tubes at elevated temperature”, “Study on internal high pressure forming of light weight components”, “Study on tube hydroforming technology at elevated temperature”, “Study on internal high pressure forming of tailor welded tube” from NSFC, and project “Study on mechanism of magnesium alloy tube hydroforming at elevated temperature” for the Doctoral Program of Higher Education of China, the mechanism of internal high pressure forming and its key technologies are investigated. Great progress is made and important results are achieved in terms of the laws of plastic deformation, wrinkling and fracturing behavior, increase of forming limits and reduction of forming pressure, hydro expanded connecting, hydroforming at elevated temperature, hydroforming of tailor welded tube, and important applications have been achieved and reported in the fields of automobile and aviation etc.. Bending, preforming and hydroforming. As for TPB/BT, hydrobulging, axial feeding and calibration are often needed. The plastic deformation process and instability behavior of these three types of parts are studied by experiment and theoretical analysis. All stress states during IHPF are positioned on the plane stress yield locus. The force analysis, stress state figure and strain state figure are given for each forming process. The stress locus of typical points during whole IHPF process has also been described and analyzed. The model of thickness dividing circle (TDC) for TPVD and the V shaped constant thickness line for Y shaped branch tube has been proposed.