This work derives internal pressure induced stresses in material imbedded with
square-shaped microchannels. The first part provides background on microchanneled
materials at micro and nanoscale to motivate investigating the stress and
deformation states. The second part develops a simplified model to characterize the
plastic flow and/or motion of dislocations within crystalline, microchanneled
materials. The model helps identify slip bands around the channels under plane
strain deformation conditions. The third part derives solutions to the stress states
around the microchannels, obtaining closed form solutions which hold for
regions containing and away from the channel boundary. Figures depict
the stress solutions in both physical and stress space. The results predict
nonuniform deformation states around the channels and also reveal the yield
conditions associated with the plastic flow along different slip bands. The work
concludes with case studies on the stress states of microneedles containing square
microchannels for applications such as fluid injection, nanofiber growth, and cell
registration.
Keywords
microchannel, anisotropic deformation, stress field,
plastic flow, nanocrystalline material
