考虑附加接触变形的冷轧板带卷取过程模拟

Simulation of cold rolling strip coiling process considering additional contact deformation

在卷取过程中,由于卷取张力的作用与板带的弯曲变形会使带卷内部产生压应力,随着卷取层数的增多,压应力会增大。在实际生产中,由于板带存在表面粗糙轮廓,在压应力的作用下,除了板带本身会发生弹性变形外,各层表面粗糙轮廓相互接触时,在径向方向上也会产生附加接触变形,这在很大程度上影响了带卷内部的应力分布。在传统的解析方法中,卷取过程被视为薄壁筒逐层嵌套的轴对称模型。该模型往往通过改变径向弹性模量来体现层间接触带来的附加变形,然而当板带的材料、厚度以及表面粗糙度不同时,采用该方法计算径向弹性模量可能会出现偏差,且逐层嵌套模型与实际的缠绕型卷取存在差异。对于该差异,采用有限元方法对卷取过程的模拟更符合实际情况,但是针对具有附加接触变形的有限元研究未见报道。因此,为了克服上述方法中存在的不足,利用有限元软件MSC. Marc通过垫片单元建立了考虑接触附加变形的板带卷取模型,通过叠片压缩试验得到了板带附加变形量与压力的变化规律曲线,并将该曲线引入垫片单元来考虑接触附加变形,进而研究附加接触变形对带卷内部应力与卷筒所受压力的影响。

During the coiling process,due to the effect of coiling tension and the bending deformation of the strip,compressive stress will be generated inside the strip coil.As the number of coiling layers increases,the compressive stress will increase.In actual production,due to the presence of rough surface contours on the strip,in addition to elastic deformation of the strip itself under compressive stress,when the rough surface contours of each layer come into contact with each other,additional contact deformation occurs in the radial direction.The additional contact deformation will greatly affect the stress distribution inside the strip coil.In traditional analytical methods,the coiling process is regarded as an axisymmetric model of thin-walled cylinders nested layer by layer.This model often reflects the additional deformation caused by interlayer contact by changing the radial elastic modulus.However,for different materials,thicknesses,and roughness,using this method to calculate the radial elastic modulus may cause errors,and there are differences between the nested model layer by layer and the actual winding type coiling.For this difference,using finite element method to simulate the coiling process accords with the actual situation better,but there is no report on finite element research with additional contact deformation.Therefore,in order to overcome the shortcomings of the above methods,the finite element software MSC.Marc is used to establish a strip coiling model,and the additional contact deformation is considered by gasket elements.The variation curve between the additional deformation of the strip and the pressure is obtained through the laminated compression experiment.Then,the curve is introduced into the gasket element to consider additional contact deformation.Furthermore,the effect of additional contact deformation on the internal stress of the coil and the pressure on the mandrel is studied.