 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Finite Element Method for Creep Testing of High Density Polyethylene Lubricant Oil Bottles) ผู้เขียน: นายชาคริต สุวรรณจำรัส, อาจารย์ ,  เอกชัย ชัยชนะศิริ สื่อสิ่งพิมพ์:pdf AbstractStacking is one method for storing many lubricant oil bottles. Bottles on the lower storey may collapse after storage for a long time because of the creep behavior of bottle materials. To avoid bottle collapse, creep testing of the bottle is required to obtain the relation between deformation and the time a bottle is under creep load. This relation can be used to manage the storage time and to improve bottle shape. Unfortunately, the identification of creep resistance for lubricant oil bottles may take more than one month. This is not satisfactory considering the market competition for container products. Therefore, this study used the finite element method (FEM) to simulate the creep behavior of high density polyethylene (HDPE) lubricant oil bottles and compared the experimental results to validate the FEM. Sample 1 L and 6 L bottles with masses of 55 and 310 g, respectively, were tested and simulated. From the results, the overall difference of deformation between the FEM and experimental samples for the 1 L and 6 L bottles was 16.20 and 13.91%, respectively. However, the FEM was able to capture the trend of bottle deformation. The weak points of 1 L and 6 L bottles were the shoulder and the handle of the bottle, respectively. The FEM results can be applied to manage the storage time of lubricant oil with regard to stacking and to developing the design of the lubricant oil bottle as well. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Development of a Wear Testing Machine for Dental Crown Application) ผู้เขียน:Panya Aroonjarattham, นายชาคริต สุวรรณจำรัส, อาจารย์, เอกชัย ชัยชนะศิริ สื่อสิ่งพิมพ์:pdf AbstractA three axes wear testing machine for a dental crown was developed for human tooth application. There were two main sections of the controllers: the application of an AC servomotor (Z-axis) for creating and controlling the force which is used in testing and the application of a step motor (X-axis and Y-axis) for creating and controlling the motion. This study aimed to compare the ability of the controlling force of the AC servomotor on two different surfaces—a smooth fl at surface and a dental crown surface. Three testing cases were considered at frequencies of 0.5, 0.75, and 1 Hz in a range of motion of 1 mm: 1) simulating the force of chewing (0–60 N) and the motion of a circular process, 2) simulating a constant force (60 N) of one way movement in a circular process and 3) simulating a constant force (60 N) of the reciprocating movement in a circular process. The machine was tested using a dental crown, which was made of zirconia, by simulating the force, the motion and the various conditions of the teeth in the oral cavity. The force which occurred in all three axes was measured by the load cell. According to the experiment, the AC servomotor was able to control the force exerted on two different surfaces with nearly similar results. The average force errors on the smooth surface and the dental crown surface were 13.70 and 13.82%, respectively. The root mean square errors of the smooth surface and the dental crown surface were 17.47 and 16.99, respectively. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : The k-? Turbulence Model to Simulate the Two-Phase Flows of Fluids in Flumes using C++ Open Source Code Computational Fluid Dynamic Software) ผู้เขียน:เอกชัย ชัยชนะศิริ, นายชาคริต สุวรรณจำรัส, อาจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe governing equations of two-phase flows based on the k-? turbulence model were developed using open source computational fluid dynamic codes and open field operation and manipulation (OpenFOAM) software to simulate water flows in a flume. The water surface was modeled using the volume of fluid method with a turbulence model. The PISO (pressure implicit with splitting of operator) algorithm was used to solve the pressure-velocity coupling in the two-phase flows. The solutions of the simulations were validated using the experimental results as free surface profiles on the wall of the laboratory flume in transient and steady time periods. The transient time period started from when the water was distributed into the flume until it began to overflow the top of the weirs. The steady time period accounted for the water overflowing the weirs and the surface profiles did not change. It was found that the average error of the surface profiles in the transient and steady time periods obtained from the simulations was 8.94% and 8.06%, respectively. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Simulation of Three Dimensional Liquid-Sloshing Models using C++ Open Source Code CFD Software) ผู้เขียน:เอกชัย ชัยชนะศิริ, นายชาคริต สุวรรณจำรัส, อาจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe open source computational fl uid dynamic (CFD) codes—open fi eld operation and manipulation (OpenFOAM)—were developed to simulate the three dimensional sloshing of liquid inside moving rectangular tanks. Equations governing the two-phases of fl uid were used in these simulations and the Volume of Fluid method was used to capture the free surface of the liquid sloshing. The fi nite volume method was used to solve these problems. The solutions of the simulations were validated using experiment results based on the free surface height and the pressure developed on the wall of the tanks. It was found that the average error of the surface height and the pressure obtained from the simulations were 2.33% and 6.65%, respectively. |
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