Performance analysis for electrorheological (ER) and magnetorheological (MR) fluid-based impact damper systems is evaluated on the basis of the Herschel-Bulkley shear model. Generally, ER-MR dampers have been analyzed based on the simple Bingham-plastic shear model. However, the Bingham-plastic shear model cannot well describe the behavior of the damper under conditions of high velocity and high field input. Therefore, in this study, the Herschel-Bulkley shear model, in which the constant post yield plastic viscosity in the Bingham model is replaced with a power law model dependent on shear rate, is used to assess the performance of ER-MR impact damper systems. In doing so, an ER-MR impact damper system is proposed and its governing equation of motion is derived on the basis of the Herschel-Bulkley shear model. Then, computer simulation is done to analytically evaluate characteristics of the ER-MR impact damper system under impact loads for constant current input and embedding end-stop on-off control algorithm. As an important parameter in the Herschel-Bulkley shear model, effects of the flow behavior index, n, that is the degree of shear thinning or shear thickening, on the performance of the impact damper system are shown.

No abstract

Electrorheological (ER) and magnetorheological (MR) fluid-based dampers are typically analyzed using Bingham-plastic shear flow analysis under quasi-steady fully developed flow conditions. An alternative perspective, supported by measurements reported in the literature, is to allow for post-yield shear thinning and shear thickening. A Herschel-Bulkley constitutive shear flow relationship can be used to account for such post-yield shear thinning or thickening behavior. Depending on the value of the flow behavior index number, varying degrees of post-yield shear thickening or thinning behavior can be analyzed. A nominal ER bypass damper is considered. Damping forces are analyzed by approximating the annular geometry of the ER/MR valve by parallel plates. The impact of the flow behavior index on the shear stress vs. shear rate behavior and velocity profile are also examined numerically as a function of applied electric field. Analytical damping predictions are compared using the nonlinear Bingham-plastic and Herschel-Bulkley analyses.

In shipbuilding processes, the fabrication of connection pipe between two arbitrary pipes positioned at a distance in a huge steel block is one of the most difficult and inefficient processes. In this process, the measurement of the three-dimensional relative position of pipes is dependent on manual operations in most shipyards, and results in a very tedious and inefficient procedure. So, a proper measurement system should be developed to improve the productivity and the accuracy of assembly. This paper describes the research and development of a new pipe measurement system for pipe connections including the conceptual design, the establishment of measuring procedures, the design and fabrication of a measurement system, and a system calibration with an artificial neural network algorithm. Finally, the accuracy and productivity of the proposed system are also presented in this paper after implementation of this system for actual application in shipyards.

This study sought to identify unique semiotic codes of Korean cuisine, including table settings, service styles, service ware selection, cooking techniques, and the logic behind menu composition. This research also aimed to verify that yangnyomjang reflects the code of Korean food culture. One of key findings from this study was that hidden codes of Korean food were found in their daily setup for bapsang (dining table), which was found to decodify polysemic characteristics with an emphasis on harmony. These semiotic codes were influenced by the yin and yang philosophy and impact dining activities in our daily lives. Korean bapsang, composed of bap (rice), guk (soup) and banchan (side dishes), helps every individual diner share the semiotic codes of Korean cuisine within the context of paradigm and syntagm. Yangnyomjang, a major component of the Korean menu, also represents a unique code of Korean cuisine in its structure, main ingredients, production, and usage. This study also mathematically verified that a synchronic table setting of Korean cuisine provides diners with more opportunities for potential flavor combinations, compared to the Western service setting.