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Elasto-Plasticity Behavior of Type 5000 and 6000 Aluminum Alloy Sheets and Its Constitutive Modeling
Shohei TAMURA,Satoshi SUMIKAWA,Hiroshi HAMASAKI,Takeshi UEMORI,Fusahito YOSHIDA 한국소성가공학회 2010 기타자료 Vol.2010 No.6
To examine the deformation characteristic of type 5000 and 6000 aluminum alloy sheets, uniaxial tension, biaxial stretching and in-plane cyclic tension-compression experiments were performed, and from these, r-values (r?, r45 and r90), yield loci and cyclic stress-strain responses were obtained. For the accurate description of anisotropies of the materials, high-ordered anisotropic yield functions, such as Gotoh’s biquadratic yield function and Barlat’s Yld2000-2d, are necessary. Furthermore, for the simulation of cyclic behavior, an advanced kinematic hardening model, such as Yoshida-Uemori model (Y-U model), should be employed. The effect of the selection of material models on the accuracy of the springback prediction was discussed by performing hat bending FE simulation using several yield functions and two types of hardening laws (the isotropic hardening model and Y-U model)
Kojima Tsukasa,Yamasaki Yuzo,Kamitani Takeshi,Yabuuchi Hidetake,Shirasaka Takashi,Shimomiya Yamato,Kondo Masatoshi,Hamasaki Hiroshi,Kato Toyoyuki,Nagao Michinobu,Honda Hiroshi 아시아심장혈관영상의학회 2019 Cardiovascular Imaging Asia Vol.3 No.1
Objective: The smallest diagnostically sufficient amount of contrast media (CM) should be used for coronary computed tomography angiography (CCTA) to minimize the risk of contrast- induced nephrotoxicity in elderly patients with coronary artery disease. The purpose of this study was to propose dynamic-CCTA using a low dose of CM and temporal maximum intensity projection (TMIP) and to investigate its image quality compared to standard-CCTA. Materials and Methods: Participants comprised 30 patients with coronary artery disease who underwent dynamic-CCTA and standard-CCTA using 320-row CT. Dynamic-CCTA was continuously performed at mid-diastole throughout 15–25 cardiac cycles after bolus injection of CM [103 mg iodine/kg body weight (mgI/kg)]. TMIP-CCTA was reconstructed from three-phase dynamic-CCTA data, including a phase with peak enhancement of the ascending aorta. Standard-CCTA was performed using a standard CM dose (259 mgI/kg). Image quality of both TMIP-CCTA and standard-CCTA was analyzed. Results: The amount of CM used in TMIP-CCTA and standard-CCTA was 16.2±2.6 mL and 40.1±7.3 mL, respectively. The mean effective radiation dose was not significantly different between the two methods. Mean coronary attenuation was significantly lower for TMIP-CCTA than standard-CCTA [346.9±82.8 Hounsfield units (HU) vs. 455.4±75.3 HU, p<0.05]. Image noise was significantly lower for TMIP-CCTA than standard-CCTA (20.0±3.2 HU vs. 28.1± 3.6 HU, p<0.05). There were no differences in signal-to-noise ratio and visual assessment scores between the two methods. Conclusion: TMIP-CCTA can be performed using more than 50% less CM with the same image quality as standard-CCTA.