Browse

Periodic crack formation in brittle thin film : 취성 박막에서의 주기적 균열 형성

Cited 0 time in Web of Science Cited 0 time in Scopus
Authors
Myung Rae Cho
Advisor
박윤
Issue Date
2015-08
Publisher
서울대학교 대학원
Keywords
Periodic crack, Crack path control, Brittle crack, Thin film crack, Fracture dynamics
Description
학위논문(박사)--서울대학교 대학원 :자연과학대학 물리·천문학부,2015. 8. 박윤.
Abstract
Crack, failure of materials, is recognized as separation pattern of materials. Throughout human history we have struggled to avoid and prevent this phenomenon because crack occurrence inherently means that objects already lost its original integrity and functionality. Moreover microscopic flaws placed in the materials body will easily alter its growth characteristic. So by their catastrophic growth nature, crack patterns are usually chaotic and unpredictable. But Mother Nature always has some exceptions. These periodic or ordered crack patterns are quite distinctive because not only for their rarity but also for unexplained mechanism in most of cases. Here simple but noble generation of ordered crack from thin film system is demonstrated by using conventional semiconductor fabrication techniques and its governing conditions of periodic pattern are discussed. Strong confinement of thin film crack and arbitrary steering of its propagation are realized by inserting thin metallic layer, thin polymeric layer and even atomically thin graphene layer in between substrate and brittle thin film. This thin interlayer-mediated controllability comes from local debonding of brittle medium or effective analogues of debonding due to relatively weak adhesion or elastic softness of interlayer. Following experiments and numerical calculation using Extended Finite Element Method (XFEM) from our study reveal that this wavy crack is intrinsically analogous to so called brittle adhesive crack. Previous studies of periodic cracks such as metallic insertion layer, self debonding sol-gel film, and even drying colloidal film, could be explained by similar mechanism. This finding could provide simple analogy on various ordered periodic crack systems existing in nature. And also this simple but noble method to control crack path could lead to the development of new concept of nano fabrication techniques.
Language
eng
URI
http://dcollection.snu.ac.kr:80/jsp/common/DcLoOrgPer.jsp?sItemId=000000066942
Files in This Item:
Appears in Collections:
College of Natural Sciences (자연과학대학)Dept. of Physics and Astronomy (물리·천문학부)Physics (물리학전공)Theses (Ph.D. / Sc.D._물리학전공)
  • mendeley

Items in S-Space are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse