Proposal for material viscoelasticity evaluation method under impact load

A novel practical method for evaluating the viscoelasticity of materials under impact load is proposed. The method is characterized by the fact that preparation of the test specimen is very easy and the testing time is very short. In the method, a mass that is levitated with a pneumatic linear bearing, and hence encounters negligible friction, is made to collide with a material under test. During the collision the Doppler frequency shift of a laser beam reflecting from the mass is accurately measured using an optical interferometer. The velocity, position, acceleration and inertial force of the mass are calculated from the measured time-varying Doppler shift. To demonstrate the high performance of the proposed method, the impact response of a gel block is highly accurately determined by means of the proposed method.