Abstract
By means of ping-pong balls, the dynamic buckling behaviours of thin-walled spherical shells under impact loading are studied both experimentally and numerically. First, the quasi-static tests were conducted on an MTS tester, in which the ball was compressed onto a PMMA plate. Apart from the force-displacement relationship, the evolution of the contact zone between the ball and the plate was obtained by a digital camera. In the impact tests, ping-pong balls were accelerated by an air-gun and then impinged onto a rigid plate with the velocity ranging 10–45 m/s. The local dynamic buckling processes of the ball were recorded by a high-speed digital camera, from which the impact duration, the maximum contact diameter, as well as the contact diameter at snap-through buckling under different impact velocities were obtained. It is found that with the same size of contact zone, the dynamic energy absorption of the ball is much larger than that in the quasi-static tests. To understand the dynamic effects in the impact process, numerical simulations were performed by using different material properties and different impact velocities. The comparison between the experimental and numerical results show that the kinetic energy absorption of the ball is induced by the strain-rate effect, local vibration of the ball and viscous-elastic effect, respectively.
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