连续退火薄板带屈曲起皱行为的试验研究

Experimental Study on Buckling Behavior of Continuous Annealed Sheet

为了研究薄板带材在连续退火过程中屈曲起皱规律,采用非接触式网格应变仪作为薄板起皱高度测量设备,设计了不均匀拉伸试验。试验可以准确获得试样中心起皱高度与拉伸时间、拉伸载荷的对应曲线,并可观测到试样在拉伸过程中的起皱行为及其发展过程。通过对比发现,夹持端形状为梯形的试样达到临界起皱状态所需的拉伸载荷低,且在夹持端不易产生应力集中,比夹持端为矩形的试样更适合用于测试塑性差的材料。通过试验发现,试样的长度和厚度对带材屈曲临界载荷和起皱临界载荷有十分重要的影响,当试样长宽相等且厚度较薄时,带材更容易起皱。

In order to study the buckling rule of thin strip during continuous annealing,a non-contact mesh strain gauge was used as the measuring equipment for the wrinkling height of thin plate,and a non-uniform tensile test was designed.The wrinkling height and tensile time,tensile load curve of the specimen can be accurately obtained by the test.The wrinkling behavior and development process of the specimen can be observed during the tensile process.By comparison,it is found that the tensile load required to reach critical wrinkling for the specimen with trapezoid shape of the clamping end state is low,and the stress concentration is not easy to occur at the clamping end,which is more suitable for use in materials with poor plasticity than the rectangular gripping end specimen.It is found that,the length and thickness of the specimen have a very important effect on the critical buckling load and the critical wrinkling load of the strip.When the specimen length and width are equal and the thickness is thin,the wrinkling of the strip is easier.