Optimal manufacturing method for self-healing microcapsules in damaged composite structures

Abstract

A new method for manufacturing self-healing microcapsules for repairing damaged composite structures is proposed to control the size of microcapsules without controlling the stirring speed and to stabilize the flow in an agitator to suppress cavitation. Compared with the conventional method, when microcapsules are prepared with a mesh inserted into the agitator, cavitation is reduced during the stirring process, thereby stabilizing the internal flow and suppressing the phenomenon of lumping of the shell material around the rotating shaft. Particle size analyzer observations showed that the size of the microcapsules decreased and the distribution became uniform after the insertion of the mesh. Numerical analysis was performed by modeling the agitator to investigate the velocity field, turbulent kinetic energy, and vorticity in the agitator. The analysis showed that a large ring-shaped vortex caused by the rotation of the impeller was divided into small vortices by the mesh. Moreover, due to the insertion of the mesh, the turbulent kinetic energy was constant and the vorticity was increased, resulting in smaller and uniformly distributed microcapsules.