高强钢板自由温弯曲成形及回弹反馈控制研究

high-strength steel plate bending parts have been widely used in mechanical engineering, automobile chassis etc. Because of its cold bending trend to arise crack, excessive springback and poor consistency of production, the warming bending for it is put forward to solve problems above. But the temperature in the warm bending process and punch stroke strong influence each other, so the comprehensive control of cracking and springback compensation is need. In addition, the springback is also sensitive to fluctuations of temperature and material performance parameters from nominal values, so precise control of forming and springback compensation problem is more prominent. In response to this situation, the current project is to be carried out to optimize high-strength steel warm bending process and springback feedback online control. Firstly, Prediction models of forming shape of high-strength steel for warm bending process are created. A springback prediction model is created consider variable temperature of plate in unloading phase. The methods of compensation springback and cracking control of high strength steel plate were established, and the bending compensation law based on punch stroke and the bending compensation law based on the temperature were determined. The closed loop control model for the bending compensation law based on punch stroke and the bending compensation law based on the temperature are established respectively. Based on the control theory, studies the phenomenon of over bending and less bending of the control model were studied. On line feedback control of bending and springback of high strength plate is realized combined machine vision technology. The study on this project is a basis for further production intelligent equipment for high-strength steel warm bending process.

高强钢中厚板弯曲件在汽车底盘、工程机械中应用广泛，因其冷弯曲易产生开裂、过量回弹和一致性差等问题，力求温弯曲工艺解决上述问题，但温弯工艺中弯曲行程和成形温度强影响成形，需要综合控制开裂和补偿回弹，加之回弹对温度和材料性能等参数偏离名义值波动较敏感，精确控制成形及补偿回弹问题更突出。针对这一现状，拟开展高强钢板自由温弯曲成形及回弹在线反馈控制研究。该项目拟建立自由温弯曲成形极限预测模型和回弹预测模型。综合建立高强钢板自由温弯曲回弹补偿和开裂控制工艺方法，确定板料基于行程的过弯补偿规律和基于温度的弯曲补偿规律。分别建立高强钢板自由定温或微变温度条件下行程补偿弯曲回弹闭环控制模型和高强钢板自由弯曲回弹定行程温度补偿闭环控制模型。基于控制理论，研究控制模型的过弯和欠弯曲现象，确定合理系统参数。联合机器视觉技术实现高强板自由温弯曲成形及回弹在线反馈控制，为生产智能专用装备奠定坚实的基础。

高强钢中厚板弯曲件在汽车底盘、工程机械中应用广泛，因其冷弯曲易产生开裂、过量回弹和一致性差等问题，力求温弯曲工艺解决上述问题。针对这一现状，拟开展高强钢板自由温弯曲成形及回弹在线反馈控制研究。首先基于不同温度的应力应变数据比较了Voce、Voce++、Voce+ Voce、ludwik几种不同的本构模型对材料数据点的适用度，提出了柔性融合本构模型。确定了ludwik和voce模型的弯曲积分模型，针对预测模型后期载荷下降问题，构造了线性搜索与二分算法联合的求解算法，建立了高强钢板自由温弯曲成形及回弹预测模型。研究了不同成形温度、凹模跨度、凸模圆角半径、凹模圆角半径、成形行程、厚度条件下高强钢板自由温弯曲回弹规律。建立高强钢板自由温弯曲回弹工艺控制方法，弯曲行程保持不变，研究不同温度、不同曲率半径下板料基于成形温度的弯曲补偿规律。分析了整个变形过程中成形温度不变或微变温条件下不同温度、不同行程、不同曲率半径下板料过弯补偿行程量，基于识别方法实现了热弯曲回弹波动性的补偿方法，基于波动数据利用神经网络实现了温弯曲回弹补偿模型。利用abaqus VUMAT二次开发接口，开发了含剪切效应的细观损伤隐式本构模型，分析了非耦合断裂准则和耦合断裂准则的适用性，建立了考虑弯曲剪切效应的弯曲耦合断裂预测模型，开发了联合ABAQUS软件的优化程序，实现了耦合断裂本构模型中材料参数的逆向自标定方法，确定了高强钢板自由温弯曲成形工艺参数可行域。分析了不同温度，不同变形阶段下的弯曲断裂过程，得出了在不同三轴度和罗德角下的裂纹扩展机理和材料的初始损伤以及孔洞集聚增长机理。建立了高精度的弯曲设备，基于labview技术开发了基于软件控制的热弯曲系统，完成了智能专用装备样机开发，为转化应用奠定了基础。