Capsule damaged by an enclosed microswimmer

Capsules, a thin deformable membrane confining liquid inside, are relevant for applications such as microfabrication, bioengineering and targeted drug delivery. With a capsule, certain substance can be released in a controlled manner and such release need a capsule to be broken. However, breaking of a capsule from the inside is rarely studied, so we focus on the breaking of a capsule by a microswimmer trapped inside in a numerical way. Due to small size of a capsule and microswimmer, we assume that the flow field is governed by the Stokes equation, which is solved by a boundary element method. We also assume the capsule membrane to be a 2-dimensional hyper-elastic material, which is calculated by a finite element method. Damage of capsule membrane is considered as quasi-brittle damage corresponding to membrane deformation. We find out the connection among damage of capsule, capillary number, and swimming mode of microswimmer.