Tumor-initiating activity of fluorinated 5-methylchrysenes.

Abstract

Structured and layered thin sheets are used in a variety of innovative applications, e.g. flexible displays, rollable solar cells or flexible electronics.Stacks of different materials, with often highly complex interconnects between layers, are thereby used, which are typically loaded in bending combinedwith intrinsic thermo-mechanical mismatches. As a result, different failure mechanisms at the level of the layered substructure occur, which constitutes aserious reliability concern. This paper deals with the two-scale homogenization of structured thinsheets, whereby a higher-order through-thickness representative volume element (RVE) is used. The methodology relies on the computationalhomogenization of the mechanics of microstructures, for which first-order and second-order solution strategies have been developed in the past decade. Theupscaling of the deformation of structured thin sheets towards a shell-type continuum is second-order in nature. The higher-order kinematics is definedon the basis of a microstructural RVE, which represents the full thickness of the macroscopic structure and a periodic in-plane cell (e.g. a single pixel in a flexible display). The elaboration of the boundary conditions and the solution of the micro-scale boundary value problem are discussed. The obtained microscale stress state is homogenized towards a 3D macroscopic shell structure, forwhich detailed aspects will be emphasized. The coupled numerical solution strategy is briefly outlined. Finally, an example is given and the applicationto a number of practical problems is highlighted, where the solution provides direct information on each scale. The incorporation of failure events at thesubstructure level is thereby naturally at hand.