Mechanical property study of soft spheres based on impact analysis using the Kelvin–Voigt fractional derivative model

Some natural materials such as the soft viscoelastic spheres cells, are difficult to create geometricuniform specimens to test their mechanical properties, and thus new measurement methods should be developed. In this study, a method to measure the mechanical property of soft viscoelastic spheres based on sphere impact dynamic analysis is proposed. The Kelvin–Voigt fractional derivative (KVFD) model, which offers a compact set of viscoelastic features appropriate for characterizing soft biological materials, is chosen to build the impact kinetic model. A soft Polydimethylsiloxane (PDMS) sphere is employed to perform impact experiment and its viscoelastic mechanical parameters including elastic modulus, relaxation time and fractional order are determined by the proposed model. Next, dynamic mechanical analysis (DMA) tests are done to check the validity of the viscoelastic mechanical parameters. The consistency of the results suggest the method proposed in this paper can be a novel high-throughput mechanical property measurement for spheroidal soft materials.