title: Pattern formation in plastic liquid films on elastomers by ratcheting.
abstract: Plastic liquids, also known as Bingham liquids, retain their shape when loads are small, but flow when loads exceed a threshold. We discovered that plastic liquid films coated on elastomers develop wavy patterns under cyclic loads. As the number of cycles increases, the wavelength of the patterns remains unchanged, but the amplitude of the patterns increases and then saturates. Because the patterns develop progressively under cyclic loads, we call this phenomenon as "patterning by ratcheting". We observe the phenomenon in plastic liquids of several kinds, and studied the effects of thickness, the cyclic frequency of the stretch, and the range of the stretch. Finite element simulations show that the ratcheting phenomenon can occur in materials described by a commonly used model of elastic-plastic deformation.
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. clarke@seas.harvard.edu suo@seas.harvard.edu.
authors.forename: Jiangshui
authors.initials: J
authors.lastname: Huang
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. clarke@seas.harvard.edu suo@seas.harvard.edu and School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, China.
authors.forename: Jiawei
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. clarke@seas.harvard.edu suo@seas.harvard.edu.
authors.forename: Lihua
authors.initials: L
authors.lastname: Jin
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. clarke@seas.harvard.edu suo@seas.harvard.edu.
authors.forename: David R
authors.initials: DR
authors.lastname: Clarke
authors.affiliation: School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. clarke@seas.harvard.edu suo@seas.harvard.edu.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Suo