Mechanical Characterization and Finite Strain Constitutive Modeling of Electrospun Polycaprolactone under Cyclic Loading
Electrospun polymers have potential for use as tissue engineered scaffolds, yet in this environment they must be able to withstand multiple cycles of loading, slightly elevated temperatures, moisture, and other degrading chemical interactions. In this work, the effects of cyclic loading, temperature, and moisture on electrospun polycaprolactone are investigated through tensile testing of dogbone-shaped specimens. Effects of fiber alignment on the macroscopic mechanical behavior are investigated by comparing samples collected on a flat plate with samples collected on a rotating cylinder. Small temperature changes had only a small effect, but moisture significantly degraded the performance of the material. In cyclic testing, the mechanical behavior changed significantly after the first cycle, suggesting that damage to the original structure occurs when first loaded. A hyperelastic representative volume element-based constitutive model was modified to capture the effect of cyclic damage and was found to reproduce the general trend quite well.