Development of Precision Springback Measurement and Bending System of Sheet Metal

钣金精密回弹测量及弯曲系统的研制

• 批准号: 12555202
• 负责人: YANG Ming
• 金额: $ 4.1万
• 依托单位: Tokyo Metropolitan University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12555202/
• 关键词: Prediction on Springback; Decrease of Elastic Modulus; Precision measurement system; Nano-Indentation; Micro instrumentation; Simulation; Database; Precision Bending; ヤング率測定; 微視的測定評価; FEMシミュレーション; 加工精度; スプリングバック評価; 画像処理; マイクロ材料物性; 応力測定; 適応

In this project, we developed two precise instruments for measuring young's modulus after large plastic deformation and distribution of internal stress of the workpiece, and attempt to calculate the springback from the measured young's modulus anc stress. The instrument for measuring young's modulus consists of a laser interferometer and optical extensometer. The stress sensor consists of magnetic field generator and semi-conduct magnetic detector based on hall effect.Experimental results show that the young's modulus measurement instrument is capable of measuring young's modulus of the test piece at beginning and after more than 20% plastic deformation with the same accuracy, and the accompanying stress in the tensile test was proportional to measured magnetoresistance of workpiece. It is found that the young's modulus decreased according to increase of plastic strain, and the young's modulus decreased to 75% of initial value after deformation with 20% plastic strain. Furthermore, the … More variation in the young's modulus was applied to predict the springback value by using FEM simulation. The results show that prediction of springback with varied young's modulus was more accurate than using only initial value.In order to clarify the mechanism of the changes in elastic modulus due to the plastic strain, microscopic measurement of material properties was performed. The changes of through-thickness distribution for mild-steel sheets were measured by analyzing the cross-sectional microphotographs of material structure. Furthermore, the elastic modulus and hardness around a grain was investigated by a nano-indentation test for measuring distribution of regional material properties. The results show that the elastic modulus decrease near the grain boundary, and the decrease of the regional material properties could significantly influence on the macro material properties, such as springback value. It's caused by piled-up dislocations, which may lead to increase of spring-back.FE simulation of V-bending process is carried out for the practical V-bending die. The discrepancies between the simulated and experimental results are evaluated in both laboratorial and practical V-bending processes. An adaptive filter to compensate for the discrepancies is proposed. The modified simulation results are stored in a database and used in the intelligent process control system based on the database developed by the authors. The AI control system of the V-bending process was evaluated by bending several kinds of materials. The results show that the FEM simulation database with the online adaptive filter is effective for the precision process control, and compatible to the practical process. Less

在本项目中，我们开发了两种精密仪器，用于测量工件在大塑性变形和内应力分布后的杨氏模量，并试图通过测量的杨氏模量计算应力下的回弹。测量杨氏模量的仪器由激光干涉仪和光学伸长仪组成。应力传感器由磁场发生器和基于霍尔效应的半导体磁探测器组成。实验结果表明，杨氏模量测量仪能够测量试件在初始和20%以上塑性变形后的杨氏模量，精度相同，拉伸试验中伴随的应力与被测工件的磁阻成正比。结果表明，随着塑性应变的增大，杨氏模量减小，当塑性应变为20%时，杨氏模量减小到初始值的75%。此外，采用有限元模拟方法，利用杨氏模量的变化来预测回弹值。结果表明，不同杨氏模量对回弹的预测比仅使用初始值更准确。为了弄清塑性应变引起弹性模量变化的机理，对材料性能进行了微观测量。通过分析材料结构的截面显微照片，测量了低碳钢薄板通过厚度分布的变化。此外，通过纳米压痕试验研究了颗粒周围的弹性模量和硬度，以测量材料区域性能的分布。结果表明：弹性模量在晶界附近降低，材料局部性能的降低对材料回弹值等宏观性能有显著影响；这是由堆积的位错引起的，这可能导致回弹增加。对实际的v形弯曲模具进行了v形弯曲过程的有限元仿真。在实验室和实际的v型弯曲过程中，对模拟结果和实验结果之间的差异进行了评估。提出了一种自适应滤波器来补偿误差。修改后的仿真结果存储在数据库中，并用于基于该数据库开发的智能过程控制系统。通过对几种材料进行折弯，对v形折弯过程的人工智能控制系统进行了评价。结果表明，基于在线自适应滤波的有限元仿真数据库能够有效地进行精密过程控制，并与实际过程相适应。少

项目成果

秋山 裕太, 楊 明, 真鍋 健一, 小山 純一: "塑性変形による材料物性変化の微視的計測評価"H15年度塑性加工春期講演論文集. (2003)

Yuta Akiyama、Ming Yang、Kenichi Manabe、Junichi Koyama：“塑性变形引起的材料性能变化的微观测量评估”2003 年春季塑料加工讲座论文集（2003 年）。

Ming YANG, Takashi FUJITA, Kenichi MANBE: "Measurement of variation in Young's modulus after large deformation and simulation of Its influence on Springback Characteristic during bending"International Conference on Materials and Processing 2002. 631-636 (

Ming YANG，Takashi FUJITA，Kenichi MANBE：“大变形后杨氏模量变化的测量及其对弯曲过程中回弹特性的影响的模拟”国际材料与加工会议2002. 631-636（

Jun-ichi Koyama, Ming YANG, Ken-ichi MANABE: "Analysis of influential factors on accuracy of bending process"Proc. of ICTP. (印刷中). (2002)

Jun-ichi Koyama，Ming YANG，Ken-ichi MANABE：“弯曲加工精度的影响因素分析”，ICTP（出版中）。

Takashi FUJITA, Ming YANG: "Development of New Springback Characteristic Measurement System"Proc. Of 51th Joint Conference for Technology of Plasticity. 421-422 (2000)

Takashi FUJITA、Ming YANG：“新型回弹特性测量系统的开发”Proc.

Y.Akiyama, M.Yang, K.Manabe & J.Koyama: "Microscopic Measurement of Deformation and Material Properties of Sheet Metal by Nano-Indentation Test"Proc. Of Spring Conference for Technology of Plasticity. 429-430 (2002)

Y.秋山、M.Yang、K.Manabe