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Huajian Gao’ KEYNOTE seminar “Theory of controlled fragmentation in cold drawing: towards a mechanics-based technological platform for large-scale manufacturing of structures at the micro- and nanoscale”

Time: Thu 2021-09-23 16.15

Location: zoom

Lecturer: Professor Huajian Gao, Nanyang Technological University, Singapore

Huajian_Gao_Sept_23_2021.pdf (pdf 242 kB)

Abstract. Cold drawing is a mature and widely adopted technique in the shaping of metallic and polymeric materials in industry. Interestingly, cold drawing of a ductile cladding containing a brittle core wire or a ductile substrate with a deposited brittle film has recently emerged as a method to produce micron sized rods and ribbons through controlled fragmentation induced by local necking. While this method shows potential in providing an economic yet efficient technological platform for large-scale manufacturing of structures at the micro- and nanoscale, there is so far no theoretical guideline on how to control the size of the fragmented components. Here, we develop a theory of controlled fragmentation in cold drawing of both axisymmetric core-cladding and plane-strain film-substrate systems. The theory reveals that the process is governed by a reverse shear lag effect which gives rise to a peak tensile stress leading to controlled fragmentation near the necking zone. Of particular interest is that the fragmentation size is predicted to depend on the interfacial shear strength, geometrical dimension and stiffness of the brittle material, and therefore can be reduced via increasing the strength of interfacial interactions and/or decreasing geometrical dimensions such as the core radius or film thickness

Page responsible:Kommunikation SCI
Belongs to: KTH Solid Mechanics seminar series
Last changed: Sep 04, 2021