ARAMIS光学应变测量在QP980钢板成形极限试验中的应用

Application of ARAMIS Optical Strain Measurement in QP980 Plate FLC Test

成形极限曲线(FLC)是由钢板失效时的极限主次应变点描绘成的曲线,采用FLC可以精确评价高强钢QP980成形性能优劣,并可以方便地用在钢板冲压仿真分析中,但是成形极限试验传统的网格分析测量方式过程繁琐。ARAMIS光学应变测量系统配备双相机测量设备,采用数字散斑测量方式,可实现高精度实时测量变形,克服了传统测量方式的缺点。高强钢QP980因为强度高、延伸率较低,采用传统的检测方式不容易观察到临界失稳的状态。试验表明ARAMIS光学应变测量可以方便准确找到颈缩开始时刻,获得QP980试样失稳时的表面应变分布,采用截线法和时间相关法得到FLC。通过试样应变云图,可以进行应变路径分析,进一步观察高强钢变形特点。

The forming limit curve(FLC)is a curve connected by the main and minor limit strain points of steel plate failure.FLC can be used to accurately evaluate the forming performance of QP980 high strength steel,and can be used in the simulation analysis of steel plate stamping conveniently.However,the traditional grid analysis and measurement method of forming limit test is complicated.ARAMIS optical strain measurement system is equipped with dual-camera and adopts digital speckle measurement method,which can accomplish high-precision real-time deformation measurement and overcome the shortcomings of traditional measurement method.Due to the high strength and low elongation of high strength steel QP980,it is difficult to observe the state of critical instability by using the traditional detection method.The test in this paper shows that ARAMIS optical strain measurement can find the beginning of necking conveniently and accurately,obtain the surface strain distribution of QP980 sample when it is unstable,and obtain FLC by using the transect method and time correlation method.Strain path analysis can be carried out to further observe the deformation characteristics of high strength steel through strain distribution map.