Dynamic characterization of Roma Plastilina No. 1 from Drop Test and inverse analysis

• Inverse method to characterize parameters of soft malleable materials is presented.
• Inverse method uses as input to the penetration profile from a Drop Test.
• Proposed characterization method was validated on Roma Plastilina No. 1.
• Drop Test on Roma Plastilina No. 1 was performed at medium strain rates.

Mechanical characterization of soft malleable materials represents a research challenge due to the impossibility to perform standard tests on this type of materials. Diverse characterization procedures are found in the literature for their characterization; however, little advances have been achieved at medium strain rates. This paper presents a characterization method for soft malleable materials to determine the material parameters associated with a given constitutive model. The characterization methodology posed as an inverse problem of Drop Test is formulated and solved as an optimization procedure. The input of the optimization procedure is the experimental measurement from the impact of a steel sphere, of specific diameter, freely released from a specific height on to the soft material. Specifically, the input data consist of the penetration history captured by high speed photography. The output of the procedure is the optimum set of material parameters determined by fitting a numerical simulation to the Drop Test experimental measurements. To evaluate and validate the performance of the proposed characterization method, experiments on Roma Plastilina No. 1 were conducted.