In heterogeneous media, the scattering due to interfaces between dissimilar materials play an important role in shock wave dissipation and dispersion. In this work the influence of interface scattering effect on shock waves was studied by impacting flyer plates onto periodically layered polycarbonate/6061 aluminum, polycarbonate/304 stainless steel and polycarbonate/glass composites. The experi...

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The Medicare Modernization Act of 2003 added a new outpatient prescription drug benefit to Medicare and increased payments to private plans to induce more plan participation in Medicare. We formalize the benefits from these two expansion paths and then estimate a statistical model of plan choice that enables us to quantify these benefits. We find that expansion of drug benefits produced nearly ...

A simple thermal-mechanical model for friction stir spot welding (FSSW) was developed to obtain similar weld performance for different weld tools. Use of the thermal-mechanical model and a combined approach enabled the design of weld tools for various sizes but similar qualities. Three weld tools for weld radii of 4, 5, and 6 mm were made to join 6061-T6 aluminum sheets. Performance evaluations...

This study is a follow-up of previous work by the authors on the effects of processing variables on the deformation and fracture of 2024-T4 aluminum. In the previous work, four variables were incorporated into a Design of Experiments methodology: solution temperature, solution time, cooling rate and natural aging time. Solution time and cooling rate were found to be the most significant factors...

The residual strain profiles were measured through the thickness of friction-stir welded (FSW) plates using neutron diffraction to study the relationship between the angular distortion and the residual strain distribution. Three different weld specimens were prepared from a 6061-T6 aluminum alloy with the purpose of separating the effects of the frictional heat and plastic deformation on the re...

friction welding is widely used in various industries. in friction welding, heat is generated by conversion of mechanical energy into thermal energy at the interface the work pieces during pin rotation under pressure. a three-dimensional thermo mechanical simulation of friction stir welding (fsw) processes is carried out for aluminium alloys of 6061and 7050 where the simulation results are comp...