Effect of the Sliding of Stacked Live Loads on the Seismic Response of Structures

Dynamic interaction between sliding live loads and the structure they act on is significant in the seismic analysis and design of the structure. The problem becomes more complex when the live loads are in the form of stacks. This paper presents a numerical model to simulate the dynamic interaction between a primary structure (PS) and a set of stacked bodies lying on it. Individual bodies in the stack were termed as secondary bodies (SBs) in this study. The lowest SB in the stack interacts with the structure through friction. Similar frictional forces also exist between different levels of the stack. This numerical model was verified with a Finite Element model. A parametric study was performed on the seismic response by varying the dynamic properties of the structure and SBs. The energy dissipation is found to be significant due to sliding within the stack. A novel methodology is proposed to calculate a modified structural period (Tnew) of the structure to use in its design. It was found that the Tnew varies significantly with the structural period, mass ratios, and coefficients of friction. Finally, design equations are proposed to calculate the Tnew . Two Indian seismic hazard levels were considered for this study

Chiral spin textures creation and dynamics in a rectangular nanostructure

Controlled creation of stable chiral spin textures is required to use them as an energy-efficient information carrier in spintronics. Here we have studied the stable creation of isolated chiral spin texture (skyrmion and antiskyrmion) and its pair through the magnetization reversal of a rectangular nanostructure using spin-polarized currents. An isolated spin texture is created through a negative current pulse. Dynamics of the stable spin texture are explored under external magnetic fields, and the resonant frequencies are calculated. A stable skyrmion pair is created using an asymmetric current pulse, and their interaction is studied using the Thiele equation. The stability of isolated or paired spin texture depends on the DMI strength, spin-polarized current density, and pulse duration. In addition, the stability of the skyrmion pair depends on their initial separation, and a threshold for the separation between skyrmions of 78 nm is observed.Comment: 29 pages, 11 figures, 2 extra figure

Developing empirical relationships to estimate adhesion bonding strength and lap shear bonding strength of HVOF sprayed WC-CrC-Ni coatings on AISI 304 L stainless steel

609-620High velocity oxygen fuel (HVOF) sprayed cermet coatings are extensively used to combat erosion-corrosion in naval applications and in slurry environments. HVOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate and spray distance have significant influence on coating characteristics like adhesion bond strength and shear strength. This paper presents the use of statistical techniques in particular response surface methodology (RSM), analysis of variance and regression analysis to develop empirical relationships to predict adhesion bond strength and lap shear bond strength of HVOF sprayed WC-CrC-Ni coatings. The developed empirical relationships can be effectively used to predict adhesion bond strength and lap shear bond strength of HVOF sprayed WC-CrC-Ni coatings at 95% confidence leve