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Shahraki, Mehdi,Sohrabi, Mohammad Reza,Azizyan, Gholam Reza,Narmashiri, Kambiz Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.2
In past years, numerous problems have vexed engineers with regard to buckling, corrosion, bending, and overloading in damaged steel structures. This article sets out to investigate the possible effects of carbon fiber reinforced polymer (CFRP) and steel plates for retrofitting deficient steel square hollow section (SHS) columns. The effects of axial loading, stiffness, axial displacement, the position and shape of deficient region on the length of steel SHS columns, and slenderness ratio are examined through a detailed parametric study. A total of 14 specimens was tested for failure under axial compression in a laboratory and simulated using finite element (FE) analysis based on a numerical approach. The results indicate that the application of CFRP sheets and steel plates also caused a reduction in stress in the damaged region and prevented or retarded local deformation around the deficiency. The findings showed that a deficiency leads to reduced load-carrying capacity of steel SHS columns and the retrofitting method is responsible for the increase in the load-bearing capacity of the steel columns. Finally, this research showed that the CFRP performed better than steel plates in compensating the axial force caused by the cross-section reduction due to the problems associated with the use of steel plates, such as in welding, increased weight, thermal stress around the welding location, and the possibility of creating another deficiency by welding.
Mehdi Shahraki,Mohammad Reza Sohrabi,Gholam Reza Azizyan,Kambiz Narmashiri 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.2
In past years, numerous problems have vexed engineers with regard to buckling, corrosion, bending, and over-loading in damaged steel structures. This article sets out to investigate the possible effects of carbon fiber reinforced polymer (CFRP) and steel plates for retrofitting deficient steel square hollow section (SHS) columns. The effects of axial loading, stiffness, axial displacement, the position and shape of deficient region on the length of steel SHS columns, and slenderness ratio are examined through a detailed parametric study. A total of 14 specimens was tested for failure under axial compression in a laboratory and simulated using finite element (FE) analysis based on a numerical approach. The results indicate that the application of CFRP sheets and steel plates also caused a reduction in stress in the damaged region and prevented or retarded local deformation around the deficiency. The findings showed that a deficiency leads to reduced load-carrying capacity of steel SHS columns and the retrofitting method is responsible for the increase in the load-bearing capacity of the steel columns. Finally, this research showed that the CFRP performed better than steel plates in compensating the axial force caused by the cross-section reduction due to the problems associated with the use of steel plates, such as in welding, increased weight, thermal stress around the welding location, and the possibility of creating another deficiency by welding.
Strengthening of deficient steel SHS columns under axial compressive loads using CFRP
Mehdi Shahraki,Mohammad Reza Sohrabi,Gholamreza Azizyan,Kambiz Narmashiri 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.1
Numerous problems have always vexed engineers with buckling, corrosion, bending, and over-loading in damaged steel structures. The present study aims to study the possible effects of Carbon Fiber Reinforced Polymer (CFRP) for strengthening deficient Steel Square Hollow Section (SHS) columns. To this end, the effects of axial loading, stiffness values, axial displacement, the shape of deficient on the length of steel SHS columns were evaluated based on a detailed parametric study. Ten specimens were tested to failure under axial compression in laboratory and simulated by using Finite Element (FE) analysis based on numerical approach. The results indicated that the application of CFRP sheets resulted in reducing stress in the damage location and preventing or retarding local deformation around the deficiency location appropriately. In addition, the retrofitting method could increase loading the carrying capacity of specimens.
Mehdi Mollakarimi Khouzani,Alireza Shahraki 대한산업공학회 2020 Industrial Engineeering & Management Systems Vol.19 No.1
Cellular manufacturing system (CMS) is one of the most important applications of the group technology (GT), with the production and management of parts and machines which have similar specifications and can move from batch production to mass production. Due to both the rapid changes in production technology and the CMS’s dependence on the demand for the most often uncertain part, researchers have designed mathematical models for designing the layout problem in a DCMS in previous research. In this study, an attempt has been made to review the assumptions in mathematical models of a DCMS and in the end, gains and gaps in this the field should be mentioned. This paper is the type of secondary study. According to the nature of the study which is qualitative, the grounded theory (GT) method has been used by reviewing previous research. A research population is a collection of articles that refer to various features in mathematical model of a DCMS. The results of the study showed that the concentration of many researchers in the mathematical models of the DCMS have been on two phases of cell formation (CF) and cell layout (CL), and they do not consider cell Scheduling (CS) stage. Therefore, a comprehensive mathematical model which considers all three phases for designing a DCMS has not been provided. In previous research, treated to mathematical models in a DCMS important assumptions such as uncertain demand, multipurpose machines, multi-skilled labor, machine reps, re-configuring cells, and machines are less noticeable. To solve the mathematical models in a DCMS, many researchers have been used (Ga) and they can also use heuristic and meta-heuristic algorithms.