宽厚板四点弯曲压力矫平理论建模与有限元分析

Theoretical modeling and finite element analysis of four-point bending flattening for heavy steel plate

宽厚板厂采用压头可移动式压平机进行厚规格板材矫平,压下参数的设定多基于人工经验,制约了生产效率和产品质量的提升。为了进一步提高压平机的矫直精度和工作效率,尤其是针对弯曲半径较大的板材,提出四点弯曲压力矫平方案。运用弹塑性力学理论并结合压力矫平过程的特点,建立宽厚板四点弯曲压力矫平模型;在材料力学性能参数和初始挠度已知的情况下,自动计算出压平力和反弯量等压下参数;通过对不同板宽、板厚、跨距和屈服强度等工艺参数的设定,根据模型计算出的数据采用有限元模拟压力矫平过程,计算出压平后板材的平直度。结果表明,各种工况均满足工业上宽厚板平直度要求,如在板厚大于25 mm、屈服强度小于460 MPa的情况下,板材的不平度均小于7 mm/m,验证了模型的可靠性。

Heavy steel plate factories use movable head flattening presses to flatten thick plate, and the setting of pressing parameters is mostly based on manual experience, which restricts the improvement of production efficiency and product quality. A four-point bending flattening scheme is proposed in order to further improve the straightening accuracy and working efficiency of the flattening machine, especially for the plate with large bending radius. A four-point bending flattening model of heavy steel plate is established according to the theory of elastic-plastic mechanics and the characteristics of flattening process. The flattening force and reverse bending value can be calculated when the mechanical property parameters and initial deflection of the plate are known. By setting different process parameters such as plate width, plate thickness, span and yield strength, the process of flattening is simulated by finite element according to the data calculated by the model, and the flatness of the flattened plate is calculated. The results show that all kinds of conditions can meet the flatness requirements of heavy steel plate in industry, such as the unevenness of plate is less than 7 mm/m when the thickness is greater than 25 mm and the yield strength is less than 460 MPa, which verifies the reliability of the model.