Simulation and Retargeting of Complex Multi-Character Interactions
Yunbo Zhang, Deepak Gopinath, Yuting Ye, Jessica Hodgins, Greg Turk, Jungdam Won
Advanced Materials Journal
The rheological parameters required to print viscoelastic nanoparticle suspensions toward tough elastomers via Digital Light Synthesis (DLS) (an inverted projection stereolithography system) are reported. With a model material of functionalized silica nanoparticles suspended in a poly(dimethylsiloxane) matrix, the rheological-parameters-guided DLS can print structures seven times tougher than those formed from the neat polymers. The large yield stress and high viscosity associated with these high concentration nanoparticle suspensions, however, may prevent pressure-driven flow, a mechanism essential to stereolithography-based printing. Thus, to better predict and evaluate the printability of high concentration nanoparticle suspensions, the boundary of rheological properties compatible with DLS is defined using a non-dimensional Peclet number (Pe). Based on the proposed analysis of rheological parameters, the border of printability at standard temperature and pressure (STP) is established by resin with a silica nanoparticle mass fraction (ϕsilica) of 0.15. Above this concentration, nanoparticle suspensions have Pe > 1 and are not printable. Beyond STP, the printability can be further extended to ϕsilica = 0.20 via a heating module with lower shear rate to reduce the Pe < 1. The printed rubber possesses even higher toughness (Γ ≈ 155 kJ m−3), which is 40% higher over that of ϕsilica = 0.15.
Yunbo Zhang, Deepak Gopinath, Yuting Ye, Jessica Hodgins, Greg Turk, Jungdam Won
Harrison Jesse Smith, Qingyuan Zheng, Yifei Li, Somya Jain, Jessica K. Hodgins
Simran Arora, Patrick Lewis, Angela Fan, Jacob Kahn, Christopher Ré