Commercially pure titanium（CP Ti） has been actively used in the plate heat exchanger due to its light weight, high specific strength, and excellent corrosion resistance. However, researches for the plastic deformati...Commercially pure titanium（CP Ti） has been actively used in the plate heat exchanger due to its light weight, high specific strength, and excellent corrosion resistance. However, researches for the plastic deformation characteristics and press formability of the CP Ti sheet are not much in comparison with automotive steels and aluminum alloys. The mechanical properties and hardening behavior evaluated in stress-strain relation of the CP Ti sheet are clarified in relation with press formability. The flow curve denoting true stress-true strain relation for CP Ti sheet is fitted well by the Kim-Tuan hardening equation rather than Voce and Swift models. The forming limit curve（FLC） of CP Ti sheet as a criterion for press formability was experimentally evaluated by punch stretching test and analytically predicted via Hora＇s modified maximum force criterion. The predicted FLC by adopting Kim-Tuan hardening model and appropriate yield function shows good correlation with the experimental results of punch stretching test.展开更多
The problem of human language, arithmetic, and art was studied in the context of the definition ＂civilization＂ on the basis of Darwin＇s theory. The author defines civilization as ＂survival of the weak＂. The autho...The problem of human language, arithmetic, and art was studied in the context of the definition ＂civilization＂ on the basis of Darwin＇s theory. The author defines civilization as ＂survival of the weak＂. The author supposes that language and art were invented by the men to describe their heroic deeds for the women in order to be selected by them for reproduction. In other words, language and art became a selection criterions together with beauty and presents. Finally, the author defines language and art.展开更多
基金supported by the National Research Foundation of Korea (NRF) granted by the Korea government [2014R1A2A2A01005903]Priority Research Centers Program (2010-0020089)support from a grant [R0003356] (Tuning Professional Support Center in Daegu Metropolitan City) funded by the Ministry of Trade, Industry and Energy (MOTIE, Korea)
文摘Commercially pure titanium（CP Ti） has been actively used in the plate heat exchanger due to its light weight, high specific strength, and excellent corrosion resistance. However, researches for the plastic deformation characteristics and press formability of the CP Ti sheet are not much in comparison with automotive steels and aluminum alloys. The mechanical properties and hardening behavior evaluated in stress-strain relation of the CP Ti sheet are clarified in relation with press formability. The flow curve denoting true stress-true strain relation for CP Ti sheet is fitted well by the Kim-Tuan hardening equation rather than Voce and Swift models. The forming limit curve（FLC） of CP Ti sheet as a criterion for press formability was experimentally evaluated by punch stretching test and analytically predicted via Hora＇s modified maximum force criterion. The predicted FLC by adopting Kim-Tuan hardening model and appropriate yield function shows good correlation with the experimental results of punch stretching test.
文摘The problem of human language, arithmetic, and art was studied in the context of the definition ＂civilization＂ on the basis of Darwin＇s theory. The author defines civilization as ＂survival of the weak＂. The author supposes that language and art were invented by the men to describe their heroic deeds for the women in order to be selected by them for reproduction. In other words, language and art became a selection criterions together with beauty and presents. Finally, the author defines language and art.
