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Ophthalmic lenses are made of plastic polymeric substrates usually coated with functional treatments composed of layers, ranging from micrometers to nanometers. Each of these interfaces may lead to delamination due to poor adhesion, and therefore affect the vision and comfort of wearers. The interface between the anti-reflective stack and the hardcoat is particularly sensitive because of chemical and mechanical contrast of its materials. To better understand mechanisms that lead to loss of adhesion between the SiO2 anti-reflective layer deposited on the anti-scratch hardcoat, compression experiments are performed to induce buckling of SiO2 layer. A finite element model using the cohesive zone method is developed to enhance the characterization of interfacial properties. Geometry of buckle yielded by the model is compared against experimental results to adjust the numerical model and access interfacial properties. [ABSTRACT FROM AUTHOR]

This article deals with a research study on the behavior of spherical roller bearings (SRB) under radial load and low angular velocity. The resistive torque is analyzed and further investigations are conducted to understand the dissipative mechanisms (friction and plastic deformations) suspected of causing these losses. The issue is tackled combining both experimental torque measurements and a multi-scale numerical simulation of the system. Finally, we discuss and confront experimental and numerical results to sketch out a dissipation scheme for the load range investigated. [ABSTRACT FROM AUTHOR]