http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Haghdadi, N. (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
Haghdadi, N.,Zarei-Hanzaki, A.,Abedi, H.R.,Abou-Ras, D.,Kawasaki, M.,Zhilyaev, A.P. Elsevier Sequoia 2016 Materials science & engineering. properties, micro Vol.651 No.-
<P>This study demonstrates the evolution of microstructure and mechanical properties of a hypoeutectic Al-7Si-0.4Mg (A356) alloy processed by accumulative back extrusion (ABE) at temperatures ranging from 200 to 500 degrees C. ABE processing is one of the new severe plastic deformation techniques enabling one to produce relatively large ultrafine-grained materials in a cylindrical shape. One complete pass of ABE was estimated to introduce a reasonably homogeneous effective strain of similar to 3 as calculated by finite element analysis. Microstructural observation showed that globular alpha-Al primary phase was subdivided into fine substructures and Si particles having a fibrous shape were fragmented and spheroidized within the eutectic constituent through ABE processing. There was no evidence of homogeneous distribution of the fine Si particles in the alpha-Al phase after ABE. Mechanical testing at room temperature showed that both yield strength and ultimate tensile strength of the A356 alloy dramatically increased through ABE, especially at lower processing temperatures, as compared with the as-cast condition whereas there was no significant reduction in ductility at all processing temperatures. The experimental results were discussed with emphasis on the microstructure evolution involving dynamic recrystallization and deformation behavior including strengthening mechanisms and strain hardening in the Al-Si alloy. (C) 2015 Elsevier B.V. All rights reserved.</P>
-
Kalashemi Sajad Haghdadi,Bidgoli Mahmood Rabani,Mazaheri Hamid 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.3
In this paper, the simultaneous actions of moving force and seismic load on the dynamic displacement and optimization of the concrete bridge are studied. The sinusoidal shear deformation beam theory is employed for the modelling of the concrete bridge mathematically. The structural damping of the concrete bridge is assumed by the Kelvin–Voigt theory. Utilizing the method of energy and Hamilton’s law, the equations of motion are obtained. Three mixed numerical methods, including the integral quadrature, harmonic differential quadrature method, and Newmark technique, are presented for the numerical outcomes of the differential equations. Utilizing adaptive improved harmony search, improved harmony search, harmony search, and global harmony search algorithms, the optimization process of the concrete bridge is examined. The mentioned algorithm is improved adaptively by utilizing dynamic deflection. The harmony memory is corrected at first and second adjustments, respectively, based on emotional bandwidth and step size randomly. The optimum conditions of the concrete bridge are evaluated with various harmony existing search methods. The role of multiple parameters, including the velocity and acceleration of moving load, length and thickness of bridge, boundary conditions, and the amplitude of carrying load, in the dynamic displacement of the bridge is studied. The numerical results indicate that with increasing the velocity and acceleration of the moving train, the dynamic displacement of the concrete bridge increases. In addition, with increasing the length of the bridge, the time of maximum deflection (i.e. when the train is in the middle of the bridge) is increased. It is concluded for the concrete bridge under the seismic load that the optimum values of the bridge’s length and thickness are decreased (about 24%) and increased (about 21%), respectively. The optimum values of amplitude, velocity, and acceleration of moving train are decreased, respectively, about 34%, 33%, and 29% in the case of the concrete bridge under the earthquake load. In addition, the optimum length of the concrete bridge is decreased significantly, with increasing the moving load amplitude, velocity, and acceleration.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
