Solid State Phenomena Vol. 110

Abstract: Recently, mechanical shock failures of a flat display unit such as TFT-LCD device have been an important concern of designers. In order to achieve the mechanical shock requirement, it is necessary to perform the detailed FE analyses which could be very expensive either by the lengthy computation or by the complicated geometry modeling. The objective of this study is to propose a simplified analysis methodology to simulate impact behavior of thin glass plates. The static problem equivalent to the impact one is found from the concept of solid mechanics to estimate the maximum deflection and stress under impact loading. To show the plausibility of the proposed approach, it is applied to the idealized problem which is a two dimensional beam subjected to impact loading. Based on explicit FE analyses using the LS-DYNA FE program, it was shown that the impact problem can be solved by the equivalent static analysis which is much easier to solve in practice. Therefore, the proposed approach provides significant advantages in design optimization of a TFT-LCD device against shock failure, and enables the designer to avoid ad hoc modeling of the transient dynamics so that product design cycle could be shortened.

Abstract: The tribology of lubricated sliding vanes in the rotary compressor was investigated to replace the HFC refrigerants by the carbon dioxide. The carbon dioxide is a natural refrigerant and very favorable to environment. Because new compressors with the carbon dioxide are going to be operated under the high pressure, the tribology of sliding surfaces in the compressor becomes very important. To develop new compressors, especially rotary type, the friction and wear characteristics of sliding surfaces between a vane and a roller in the rotary compressor were evaluated in this paper. Several hard coatings, such as TiN, CrN, WC/C and two types of nitridings, were applied on vane surfaces in order to improve the tribological characteristics, and their performances were evaluated experimentally. The vane-on-disk type sliding tests were carried out under the various sliding speeds, normal loads, and carbon dioxide pressures with an exclusive high pressure wear tester. From the tests wear volume of vane surfaces applied various coatings were compared. During the tests coefficients of friction and surface temperatures were monitored. Test results showed that WC/C coatings showed good tribological properties. TiN and CrN coated vanes showed good wear resistance properties but produced high friction.