Shear-enhanced yield stress in electrorheological fluids.
We report the enhancement of yield stress in electrorheological (ER) fluids by a shear-annealing method, using creep-recovery (CR) cycles under an external electric field. The enhancement depends on the duration and the strength of the applied shear stress, as well as on the number of the CR cycles. The shear-annealing method enables the particles in the ER fluid to form microstructures with an increased yield stress, manifest as better aligned and denser columns. For a sufficiently large number of CR cycles, with an optimal combination of stress duration and shear strength, a stable state can be obtained whereby shear deformation becomes elastic.
Lau
Kai Chi
KC
Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Shi
Lihong
L
Tam
Wing Yim
WY
Sheng
Ping
P