Synchronized Heterogeneous Indentation Behavior of Viscoelastic Materials Upon Macroscopic Compression via a Distributed-Deflection Sensor

Built upon a distributed-deflection sensor, an experimental technique is presented in this paper that allows for measuring the synchronized heterogeneous indentation behavior of viscoelastic materials upon macroscopic compression. The core of the distributed-deflection sensor is a whole polymer microstructure embedded with a resistive transducer array underneath. A cylinder probe is utilized to exert macroscopic compression on a material sample placed on the distributed-deflection sensor, and the synchronized heterogeneous indentation behavior of the sample is then translated to distributed deflections of the microstructure and is recorded as distributed resistances by the transducer array. In a measurement, the input signal is the indentation depth of the probe, the output signals are the macroscopic compression load and the distributed resistance changes of the sensor. From the measured distributed load-deflection relations of a sample along its length at multiple indentation depths with the same 5s hold time and 5s recovery time, the instant and the 5s relaxed indentation modulus of a sample are extracted, revealing non-negligible effect of the neighboring regions on the indentation behavior at a location in a sample.