Acoustic metamaterials can be designed by inserting along the path of a sound wave periodically spaced side resonators. An example efficient design was recently proposed consisting perforated stacking flat annular cavities (the pancake resonator), perforation allowing propagation waves. The resonator is used in absorber mode and theoretical description absorption achieved with help theory fluid...

Introduction Perforated sheets are used in a number of industrial applications e.g. the shadow masks in colour monitor and television tubes. Their design requires the characterization of the deformation behaviour of a perforated sheet containing a large number of tiny holes. In practice, the holes are varying through the sheet thickness, however, in modelling this inhomogeneity is mostly ignore...

A comprehensive methodology that takes into account alloy solidification, shrinkage-driven interdendritic fluid flow, hydrogen precipitation, and porosity evolution has been developed for the prediction of microporosity fraction in aluminum A356 alloy castings. The mathematical models presented are implemented in a computational framework consistent with those of commercial casting codes, allow...

Higher-powered electronics are being integrated into automobiles rapidly. With these electronics comes a problem of how to cool this equipment economically. Heatsink costs have not benefited nor adapted to the high volume nature of automotive electronics. Specially shaped heatsinks are much more efficient for a given size than aluminum extrusion-based ones, most prevalent used in automobiles. H...

in this work, a tracer study on pore initiation in anodic alumina in oxalic acid was performed. effects of some experimental parameters such as applied electrical potential, electrolyte composition and heat pretreatment were evaluated. electrochemical and morphological experiments were performed using potentiostatic anodizing and scanning electron microscopy (sem) techniques, respectively. effe...

aluminum foams are a novel branch of advanced materials with superior properties. sandwich structures with aluminum foam core are good energy absorbers. in this paper, mechanical properties and energy absorption of aluminum foam sandwich panels subjected to quasi-static perforation tests with conical-nosed indenter were investigated experimentally. for this purpose sandwich panels consisting of...