G. Chagnon

Mechanical behavior of architectured photosensitive silicone membranes: Experimental data and numerical analysis

ABSTRACT The aim of this article is to provide an experimental and modeling study of an architectured photosensitive silicone membrane. Mechanical properties are dependent of UV doses used to alter the local cross-link density, resulting in a direct effect on the macroscopic mechanical behavior. A series of mechanical tests were carried out to characterize the mechanical behavior of each phase. Results are presented for various types of loading, including uniaxial, planar, and equibiaxial loading cases, for the UV irradiated and the nonirradiated material. Using the bulge test with an architectured sample, the global stretchability with minimum boundary condition perturbations was investigated. To further explore the unusual properties offered by silicone graded membranes, finite element analysis of graded architecture was performed to try to predict the stress-strain response in the bulge test. Soft-to-hard transition is tested and the macroscopic influence of interface was observed.

Simulation of Drawing of Small Stainless Steel Platinum Medical Tubes—Influence of the Tool Parameters on the Forming Limit

Tube cold drawing processes are used to reduce tube diameters and thickness, while pulling them through a conical converging die with or without inner plug. An accurate modelling of the material deformation and friction behaviour is required in order to well describe these processes.The study concerns a stainless steel platinum alloy. The material behaviour is characterised through tensile tests at strain rates as close as possible to the high strain rates reached during the drawing process. The results are fitted with an isotropic temperature‐independent Johnson Cook constitutive equation. The modelling of floating plug drawing is performed on a ABAQUS/Explicit model. Friction coefficient is difficult to estimate with mechanical experimental tests, thus an inverse analysis is carried out to fit this parameter thanks to finite element simulation and experimental drawing tests. Drawing force measurements are recorded during the forming process. The Cockroft‐Latham criterion is applied to understand the dif...