scholarly journals Mechanics of Graded Wrinkling

2016 ◽  
Vol 83 (12) ◽  
Author(s):  
Shabnam Raayai-Ardakani ◽  
Jose Luis Yagüe ◽  
Karen K. Gleason ◽  
Mary C. Boyce
Keyword(s):  
Thin Film ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Surface Topography ◽  
Analytical Modeling ◽  
Element Analysis ◽  
Surface Wrinkling ◽  
Stress States ◽  
Stiff Material ◽  
And Behavior

The properties and behavior of a surface as well as its interaction with surrounding media depend on the inherent material constituency and the surface topography. Structured surface topography can be achieved via surface wrinkling. Through the buckling of a thin film of stiff material bonded to a substrate of a softer material, wrinkled patterns can be created by inducing compressive stress states in the thin film. Using this same principle, we show the ability to create wrinkled topologies consisting of a highly structured gradient in amplitude and wavelength, and one which can be actively tuned. The mechanics of graded wrinkling are revealed through analytical modeling and finite element analysis, and further demonstrated with experiments.

A Finite Element Analysis for Magnetostrictive Thin Film Structures and Its Experimental Verification

2006 ◽  
Vol 306-308 ◽  
pp. 1151-1156 ◽  
Author(s):  
Chong Du Cho ◽  
Heung Shik Lee ◽  
Chang Boo Kim ◽  
Hyeon Gyu Beom
Keyword(s):  
Thin Film ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Geometric Feature ◽  
Hysteresis Phenomenon ◽  
Finite Element Code ◽  
Element Analysis ◽  
Element Mesh ◽  
Magnetostrictive Actuators ◽  
Large Length

In this paper, a finite element code especially for micro-magnetostrictive actuators was developed. Two significant characteristics of the presented finite element code are: (1) the magnetostrictive hysteresis phenomenon is effectively taken into account; (2) intrinsic geometric feature of typical thin film structures of large length to thickness ratio, which makes it very difficult to construct finite element mesh in the region of the thin film, is considered reasonably in modeling micro-magneostrictive actuators. For verification purpose, magnetostrictive thin films were fabricated and tested in the form of a cantilevered actuator. The Tb-Fe film and Sm-Fe film are sputtered on the Si and Polyimide substrates individually. The magnetic and magnetostrictive properties of the sputtered magnetostrictive films are measured. The measured magnetostrictive coefficients are compared with the numerically calculated ones.

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