薄壁球壳受刚性球面压缩的可视化连续变形测量研究

Study on Visualization of Continuous Deformation Measurement of Thin-Walled Spheres Compressed by Rigid Ball

利用三维数字图像相关(DIC)技术对薄壁球壳受刚性球面压缩的连续变形及失稳过程进行实验研究。实验中,由于乒乓球具有理想的弹塑性材料特性以及薄且均匀的壁厚,所以采用乒乓球作为压缩对象,以透明石英玻璃球作为刚性球面,通过配制与玻璃球折射率一致的折射液来消除因玻璃球折射导致的图像畸变影响,从而解决被测表面因遮挡而不可见的问题。利用三维DIC技术对与刚性球面接触的乒乓球表面在压缩过程中的连续变形进行直接测量。实验验证了所提方法的有效性。实验结果表明,通过三维DIC测量得到的乒乓球表面受刚性球面压缩产生的塑性环半径与理论结果非常吻合。

The continuous deformation and crushing behavior of thin-walled spheres compressed by rigid ball is researched experimentally by three dimensional digital image correlation （3D-DIC） technology. In experiment, ping pong balls are selected as thin-walled spheres because of its ideal elastic-plastic material properties and very thin but uniform wall thickness. Ping pong balls are compressed by a transparent quartz glass ball, which is regarded as a rigid body. It is emphasized that refractive index liquid is introduced to eliminate the image distortion caused by the light refraction of glass ball. 3D-DIC is employed to directly measure the continuous compression deformation of the contact surface of the ping pong balls.The experimental results demonstrate the validity of the proposed method. The plastic ring caused in the compression is measured by 3D-DIC, and the experimental value agrees well with that of theoretical prediction.