Most soft
materials behave as if they were hardened when subjected to an impact force.
The strain rate dependence of viscosity resistance is the reason for this behavior.
The authors carried out drop impact tests on several types of soft materials
under the condition of a flat frontal impact. The impact force waveform of soft
materials was found to consist of a thorn-shaped waveform and a succeeding
mountain-shaped waveform. Based on our experimental observations, we believe
that a large viscosity resistance is rapidly changed to a small resistance in
the course of the impact. In the present study, the cause of this distinct
waveform is discussed based on a dynamics model. The study applies a standard
linear solid (SLS) model in which the viscosity transient phenomenon is
considered is applied. Three types of impact force waveforms of actual soft
materials are simulated using the SLS model. Some features of the impact force
waveform of soft materials can be explained using the SLS model.
References
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