受扭圆环薄膜褶皱变形的试验研究

Experimental study on wrinkling deformation of an annular membrane under torsion

通过对圆环薄膜进行受扭试验,研究薄膜的褶皱变形机理及其随影响因素的变化规律。为减小边界条件的误差扰动,研发高精度试验装置。通过砝码和同步装置对圆环膜施加预张力,借助旋转平台施加扭矩,采用激光位移传感器对褶皱变形进行非接触测量,主要研究边界条件、预张力以及膜厚等因素对薄膜褶皱变形及其特征参数的影响规律。结果表明:随着扭转角的增加,褶皱幅值逐渐增大,由于没有二次屈曲发生,褶皱数量和褶皱半波长没有明显变化;增大预张力能够有效提高薄膜刚度,从而褶皱幅值和褶皱半波长减小,但使褶皱数量增多;膜厚增加能够提高薄膜的抗弯刚度,在相同扭转角和预张力的情况下,褶皱数量减少,但使得褶皱幅值和褶皱半波长增大。研究成果揭示褶皱因素对褶皱变形的影响规律,有助于通过其影响特性对薄膜褶皱变形进行有效控制,保证薄膜结构的形面精度。

Wrinkling deformation and its variation with the influencing factors were studied through the experiment of an annular membrane under torsion.An accurate experimental apparatus was developed to reduce the perturbation of errors resulting from boundary conditions.Pre-tensioning force was applied with weights and the home-made synchronizing equipment,and torque was exerted with the rotating platform.Wrinkling deformation was measured with the non-contacting laser displacement sensor.The research focused on the influences of boundary conditions,pre-tensioning force and thickness on the wrinkling deformation and its characteristic parameters.The results show that wrinkling amplitude increases with the torsional angle,but little change can be found in the wrinkling number and half wavelength due to the absence of secondary buckling.The increasing pre-tensioning force can reduce the wrinkling amplitude and half wavelength owing to its contribution to the membrane stiffness,but it can also induce a rise in the wrinkling number.Increase in the thickness can strengthen the bending stiffness and decrease the wrinkling number,but increase the wrinkling amplitude and half wavelength when boundary conditions and pre-tensioning force are constant.The present research reveals the effect of wrinkle-influencing factors and helps to prevent the wrinkling deformation for the surface precision of membrane structures.