板料成形接触应力及其压电测定方法研究

发布时间：2018-12-16 17:20

【摘要】：本文以高强钢板料弯曲成形和拉深成形过程为研究对象,对模具磨损控制和接触应力的演变特征进行了研究。运用塑性成形理论,计算了带凸缘的盒形件在拉深成形过程中模具圆角处的接触应力的大小,验证了理论计算结果与有限元分析结果的一致性。以高强钢板DP780的U型件为算例建立弯曲成形有限元模型,分析了不同材料参数模型对模具磨损的影响,分析结果表明：使用变化杨氏模量模型的板料对模具磨损的影响比常值杨氏模量模型要小。本文还对PVDF压电电缆的压电特性进行力电耦合有限元建模,分别求解了压电电缆在平面水平放置和半嵌入式放置下PVDF压电电缆输出电势差与输入载荷之间的关系；当PVDF压电电缆嵌入深度小于等于0.5d时,随着嵌入深度增加,PVDF薄膜层输出电势差减小；给出了PVDF压电电缆不同嵌入深度时PVDF薄膜层输出电势。同时探讨了在凹模圆角处半嵌入压电电缆对高强钢U型件弯曲成形接触应力原位测量的可行性。设计了PVDF压电电缆的标定装置,实验标定了电缆的压电系数。最后,采用实验装置对PVDF压电电缆的压电特性进行了实验测定,实测了PVDF压电电缆在平面水平放置、半嵌入式压电层输出电势差与输入载荷之间的线性关系。
[Abstract]:In this paper, the characteristics of die wear control and contact stress evolution are studied in the process of bending forming and drawing forming of high strength steel sheet. Based on the plastic forming theory, the contact stress of the box part with flange in the deep drawing process is calculated, and the agreement between the theoretical results and the finite element analysis results is verified. The finite element model of bending forming is established by taking the U-shaped part of high strength steel plate DP780 as an example. The influence of different material parameter models on the wear of die is analyzed. The results show that the influence of different Young's modulus model on die wear is smaller than that of constant Young's modulus model. In this paper, the piezoelectric characteristics of PVDF piezoelectric cable are modeled by electromechanical coupling finite element method, and the relationship between the output potential difference and the input load of PVDF piezoelectric cable under horizontal and semi-embedded placement is solved respectively. When the embedding depth of PVDF piezoelectric cable is less than or equal to 0.5 d, the output potential difference of PVDF film layer decreases with the increase of embedding depth, and the output potential of PVDF film layer is given when the embedding depth of PVDF piezoelectric cable is different. At the same time, the feasibility of in-situ measurement of contact stress in U-shaped bending of high-strength steel by semi-embedded piezoelectric cable at the corner of die is discussed. The calibration device of PVDF piezoelectric cable is designed, and the piezoelectric coefficient of the cable is calibrated experimentally. Finally, the piezoelectric characteristics of PVDF piezoelectric cable are measured by using an experimental device. The linear relationship between the output potential difference of semi-embedded piezoelectric layer and the input load is measured when the PVDF piezoelectric cable is placed horizontally in a plane.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG306

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