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 : Shiravand, M.R. (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
Seismic response of RC structures rehabilitated with SMA under near-field earthquakes
Shiravand, M.R.,Khorrami Nejad, A.,Bayanifar, M.H. Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.4
During recent earthquakes, a significant number of concrete structures suffered extensive damage. Conventional reinforced concrete structures are designed for life-time safety that may see permanent inelastic deformation after severe earthquakes. Hence, there is a need to utilize adequate materials that have the ability to tolerate large deformation and get back to their original shape. Super-elastic shape memory alloy (SMA) is a smart material with unique properties, such as the ability to regain undeformed shape by unloading or heating. In this research, four different stories (three, five, seven and nine) of reinforced concrete (RC) buildings have been studied and subjected to near-field ground motions. For each building, two different types of reinforcement detailing are considered, including (1) conventional steel reinforcement (RC frame) and (2) steel-SMA reinforcement (SMA RC frame), with SMA bars being used at plastic zones of beams and steel bars in other regions. Nonlinear time history analyses have been performed by "SeismoStruct" finite element software. The results indicate that the application of SMA materials in plastic hinge regions of the beams lead to reduction of the residual displacement and consequently post-earthquake repairs. In general, it can be said that shape memory alloy materials reduce structural damage and retrofit costs.
-
Parametric Study on Eff ect of Adding Stiff ener to Post-tensioned Steel Connection
M.R. Shiravand,A. Torabipour,S. Mahboubi 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.2
Beam-to-column connections with post-tensioned (PT) elements are used in steel moment-resisting frames to provide adequate stiff ness, strength, and ductility and to eliminate residual displacements under seismic loads. A steel PT connection has recently been developed with top and seat angles. In this connection, angles are used to dissipate energy under cyclic loading. This paper aims to investigate the infl uence of adding stiff eners to the top and seat angles on the cyclic responses of PT connections. To this end, a parametric study is performed to compare the eff ectiveness of stiff eners and some design parameters in the cyclic behavior of the PT connections. The design parameters are the angle thickness, the distance between the bolt line passing through the column and the heel of the angle (g 2 ), the PT force of the strands, and number of strands. First, the results of fi nite element analyses are compared to previously conducted experiments on PT connections with top and seat angles through a verifi cation study. In this way, fi nite element models of 23 PT connections are developed and analyzed under cyclic loading. Results indicate that adding the stiff eners to the angles, enhances the energy dissipation capacity, moment capacity, stiff ness and ductility of the PT connection much higher than improving other design parameters.
-
( Mehrdad Valipour ),( Erfan Ayubi ),( Narges Shiravand ),( Yousef Moradi ),( Abolfazl Abbaszadeh ),( Firooz Amrai ),( Shahin Mokhtari ),( Kaveh Bahmanpour ),( Kamyar Mansori ) 대한산부인과학회 2020 Obstetrics & Gynecology Science Vol.63 No.2
Objective To determine the maternal risk factors associated with preterm delivery in Iran. Methods A population-based case-control study was conducted including 48 women having preterm delivery (case group) and 100 women having term delivery (control group) between March 2007 and March 2012 in the maternity hospitals of the Selseleh County, Lorestan province, Iran. Information regarding maternal risk factors was collected by structured interview and reviewing the medical records. The maternal risk factors associated with preterm delivery were identified using univariate and multivariable logistic regression analysis after adjusting the sparse data bias. The area under the receiver operating characteristic (ROC) curves was estimated to evaluate the discrimination power of the statistical models. Results Multivariable analysis demonstrated that multiparty (odds ratio [OR], 14.23; 95% confidence interval [CI], 1.60-127.05), history of gestational diabetes (OR, 0.10; 95% CI, 0.01-0.99), thyroid dysfunction (OR, 97.32; 95% CI, 5.78-1,637.80), urinary tract infection (OR, 16.60; 95% CI, 3.20-85.92), and taking care during pregnancy (OR, 0.12; 95% CI, 0.03-0.50) had significant impact on preterm delivery after adjusting the potential confounders. The area under the ROC curve for the aforementioned maternal risk factors was 0.86 (95% CI, 0.80-0.92). Conclusion Our study provides evidence for the associations between multiparty, history of gestational diabetes, thyroid dysfunction, urinary tract infection, as well as taking care during pregnancy, and preterm delivery.
-
Impact of geometric pattern corrosion on limit failure pressure of buried gas pipelines
Nemat Hassani,S. Mohammad S. Kolbadi,Mahmud Reza Shiravand,Jafar H. Golafshani 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.5
Gas pipelines are types of structures that are highly susceptible to corrosion. Sometimes, the pipes are subjected to a thinning of the wall thickness at the inside or outside wall due to erosion/corrosion. Therefore, it is important to evaluate the strength of the pipes undergoing corrosion to maintain the integrity of the piping systems. The main purpose of this study is to understand failure aspects caused by degradation of metal due to corrosion through. The ASME standard offers a relationship for the yielding pressure of the corroded pipes which was compared with the finite element results. The results demonstrate to obtain accurate results, the ASME relationship is unreliable. Moreover, pitting corrosion must be considered critical more than of other types.
KISS연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
