title: Fracture of ceramic/ceramic/polymer trilayers for biomechanical applications.
abstract: Fracture damage in trilayers consisting of outer and inner brittle layers bonded to a compliant (polycarbonate) substrate and subjected to concentrated surface loading is analyzed. The principal mode of fracture is radial cracking at the undersurface of the inner (core) layer, even in the strongest of core ceramics--other damage modes, including radial cracking in the outer (veneer) layer, are less invasive in these all-brittle coating systems. Tests on simple trilayer structures fabricated from glasses, sapphire, and dental ceramics are used to examine the dependence of the critical load for radial fracture in terms of relative outer/inner layer thickness and modulus, and inner layer strength. An explicit relation for the critical load, based on a flexing plate model in which the outer/inner bilayer is reduced to an "equivalent" monolithic coating with "effective" composite modulus, is used to examine these dependencies. The theoretical relation describes all the major trends in the critical load data over a broad range of variables, thus providing a sound basis for trilayer design. Relevance of the analysis to dental crowns and other biomechanical applications is a central theme of the study.
authors: Department of Materials and Nuclear Engineering, University of Maryland, College Park, Maryland 20742-2115, USA.
authors: Yan
authors: Y
authors: Deng
authors: Pedro
authors: P
authors: Miranda
authors: Antonia
authors: A
authors: Pajares
authors: Fernando
authors: F
authors: Guiberteau
authors: Brian R
authors: BR
authors: Lawn
mesh_terms: D001672:Biocompatible Materials / Q000592:standards*; D001696:Biomechanical Phenomena; D002516:Ceramics; D003764:Dental Materials; D008422:Materials Testing; D011108:Polymers; D016474:Weight-Bearing
chemical_list: D001672:Biocompatible Materials; D003764:Dental Materials; D011108:Polymers