Optimization of Concrete-Filled Steel Tubular (CFST) Columns Using Meta-Heuristic Algorithms

Author(s):  
Celal Cakiroglu ◽  
Kamrul Islam ◽  
Gebrail Bekdaş

Concrete-filled steel tubular (CFST) columns are an extensively studied area due to the favorable structural characteristics of these members. In order obtain the best possible performance from these structures while reducing the cost the use of optimization algorithms is indispensable. For this reason, meta-heuristic algorithms are finding increasing application in engineering due to their high efficiency. Various equations that predict the axial ultimate load-carrying capacity (Nu) of CFST columns are available in design codes as well as the research literature. However, most of these equations are only applicable within certain parameter ranges. A recently developed set of equations that have better parameter ranges of applicability was applied in this study. Furthermore, a newly developed meta-heuristic algorithm called social spider algorithm is applied to the cross-section optimization of circular CFST columns. The improvement of the structural dimensioning under Nu constraint was demonstrated.

2014 ◽  
Vol 518 ◽  
pp. 170-177
Author(s):  
Fu Yun Huang ◽  
Guan Yu ◽  
Bao Chun Chen ◽  
Jian Zhong Li

The testing of concrete filled steel tubular (CFST) latticed columns with initial stress had been conducted under axial load. The set-ups subjected to initial stress, the curves of load to deformation as well as the hooping effect were analyzed. The trial results indicate that the CFST columns with initial stress have smaller of combined stiffness and ultimate load-carrying capacity as compared with CFST columns without initial stress. Furthermore, the presence of initial stress will advance the coming of plastic phase, and contemporary, put off the appearances of hooping effect so that it cannot be sufficient exerted, which decrease the ultimate load-carrying capacity at all. Nevertheless, the mechanical behaviour of lacing tubes does not vary with the initial stress and all the lace tubes are stayed in the elastic phase during the testing.


2000 ◽  
Vol 122 (4) ◽  
pp. 243-252 ◽  
Author(s):  
So̸ren R. Hauch ◽  
Yong Bai

In this paper, the bending moment capacity for metallic pipes has been investigated to provide criteria for optimizing the cost effectiveness in pipeline seabed intervention design. An analytical solution for the ultimate load-carrying capacity of pipes subjected to combined pressure, longitudinal force, and bending has been derived and thoroughly compared against results obtained by the finite element method. The derived equations can be used for high-strength materials with isotropic as well as anisotropic stress/strain characteristics, and may be applied for pipelines, risers, and piping if safety factors are calibrated in accordance with appropriate target safety levels. [S0892-7219(00)00504-5]


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Muhammad Ashar Naveed ◽  
Muhammad Afnan Ansari ◽  
Inki Kim ◽  
Trevon Badloe ◽  
Joohoon Kim ◽  
...  

AbstractHelicity-multiplexed metasurfaces based on symmetric spin–orbit interactions (SOIs) have practical limits because they cannot provide central-symmetric holographic imaging. Asymmetric SOIs can effectively address such limitations, with several exciting applications in various fields ranging from asymmetric data inscription in communications to dual side displays in smart mobile devices. Low-loss dielectric materials provide an excellent platform for realizing such exotic phenomena efficiently. In this paper, we demonstrate an asymmetric SOI-dependent transmission-type metasurface in the visible domain using hydrogenated amorphous silicon (a-Si:H) nanoresonators. The proposed design approach is equipped with an additional degree of freedom in designing bi-directional helicity-multiplexed metasurfaces by breaking the conventional limit imposed by the symmetric SOI in half employment of metasurfaces for one circular handedness. Two on-axis, distinct wavefronts are produced with high transmission efficiencies, demonstrating the concept of asymmetric wavefront generation in two antiparallel directions. Additionally, the CMOS compatibility of a-Si:H makes it a cost-effective alternative to gallium nitride (GaN) and titanium dioxide (TiO2) for visible light. The cost-effective fabrication and simplicity of the proposed design technique provide an excellent candidate for high-efficiency, multifunctional, and chip-integrated demonstration of various phenomena.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3468
Author(s):  
Zbigniew Kolakowski ◽  
Andrzej Teter

The phenomena that occur during compression of hybrid thin-walled columns with open cross-sections in the elastic range are discussed. Nonlinear buckling problems were solved within Koiter’s approximation theory. A multimodal approach was assumed to investigate an effect of symmetrical and anti-symmetrical buckling modes on the ultimate load-carrying capacity. Detailed simulations were carried out for freely supported columns with a C-section and a top-hat type section of medium lengths. The columns under analysis were made of two layers of isotropic materials characterized by various mechanical properties. The results attained were verified with the finite element method (FEM). The boundary conditions applied in the FEM allowed us to confirm the eigensolutions obtained within Koiter’s theory with very high accuracy. Nonlinear solutions comply within these two approaches for low and medium overloads. To trace the correctness of the solutions, the Riks algorithm, which allows for investigating unsteady paths, was used in the FEM. The results for the ultimate load-carrying capacity obtained within the FEM are higher than those attained with Koiter’s approximation method, but the leap takes place on the identical equilibrium path as the one determined from Koiter’s theory.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 229
Author(s):  
Siva Avudaiappan ◽  
Erick I. Saavedra Flores ◽  
Gerardo Araya-Letelier ◽  
Walter Jonathan Thomas ◽  
Sudharshan N. Raman ◽  
...  

An experimental investigation is performed on various cold-formed profiled sheets to study the connection behavior of composite deck slab actions using bolted shear connectors. Various profiles like dovetailed (or) re-entrant profiles, rectangular profiles and trapezoidal profiles are used in the present investigation. This experimental investigation deals with the evaluation of various parameters such as the ultimate load carrying capacity versus deflection, load versus slip, ductility ratio, strain energy and modes of failure in composite slab specimens with varying profiles. From the test results the performance of dovetailed profiled composite slabs’ resistance is significantly higher than the other two profiled composite deck slabs.


2012 ◽  
Vol 239-240 ◽  
pp. 1522-1527
Author(s):  
Wen Bo Wu ◽  
Yu Fu Jia ◽  
Hong Xing Sun

The bottleneck assignment (BA) and the generalized assignment (GA) problems and their exact solutions are explored in this paper. Firstly, a determinant elimination (DE) method is proposed based on the discussion of the time and space complexity of the enumeration method for both BA and GA problems. The optimization algorithm to the pre-assignment problem is then discussed and the adjusting and transformation to the cost matrix is adopted to reduce the computational complexity of the DE method. Finally, a synthesis method for both BA and GA problems is presented. The numerical experiments are carried out and the results indicate that the proposed method is feasible and of high efficiency.


2011 ◽  
Vol 204-210 ◽  
pp. 1415-1418
Author(s):  
De Jiang Zhang ◽  
Na Na Dong ◽  
Xiao Mei Lin

By studying the conventional algorithm of contour extraction, a new method of contour extraction in blood vessel of brain is proposed based on the MOC maximum optimization cost. First of all, the theory computes the gray differential of the image by conventional differential method to build the cost space. Then, by using dynamic programming theory, the maximum optimization cost curve in the space is extracted to serve as the specific cerebrovascular profile. The experiments show that this method ensures high efficiency in extracting cerebrovascular contour and a high accuracy in positioning cerebrovascular contour, and it diminishes the target image ambiguity caused by noise to improve the anti-interference ability of Contour extraction.


2015 ◽  
Vol 1094 ◽  
pp. 445-450 ◽  
Author(s):  
Wei Chen ◽  
Hong Hao Ma ◽  
Zhao Wu Shen ◽  
De Bao Wang

Due to the inefficiency problem of the cut blasting in rock excavation and rock breaking, a shell radial shaped charge device was proposed based of the ideal of ‘cutting to slotting’ and it was validated through experiments. For this device, the shell materials are used to be shaped materials and multiple shaped ring is designed on the circular tube. It can not only reduce charge quantity but also raise the utilization ratio of explosive energy. After explosion, multiple radial shaped charge jets can be formed along the axial line in sequence and then the surrounding rock mass would be cracked. The crack network will be formed along with the further extension of the fraction under the action of quasi static loading of detonation gas. The shell radial shaped charge device was tested through the cut blasting model experiment. Experimental results show that the utilization ratio of blasting hole nearly approaches 98% with this device. The blasting efficiency and cyclical footage can be improved effectively and the cost of drifting can also be reduced.


2021 ◽  
Author(s):  
Lin Yuan ◽  
Jiasheng Zhou ◽  
Haowei Liu ◽  
Nian-Zhong Chen

Abstract Mechanically lined pipe, which was proven to be cost-effective in transporting corrosive hydrocarbons, has been used in many offshore applications. However, one weakness of this product is that the liner is extremely sensitive to geometric imperfections and can wrinkle and collapse under severe loading. As typical damage of the pipeline, the local dent of the lined pipe involves the deformation of both the carrier pipe and the liner, which poses a severe threat to the integrity of the composite structure. In this paper, we developed a numerical framework to study the responses of the lined pipe during indentation and, more importantly, the influence of local dents on the bending capacity of lined pipes. A slight separation between the liner and the carrier pipe was observed during the indentation, depending on the indenter’s geometric feature. Under bending, the liner typically collapsed earlier than the carrier pipe, causing a considerable reduction of the critical curvature and ultimate load-carrying capacity. The evolution of the deformation of the composite structure during the bending process is presented in this paper. Parametric investigations of some vital variables of the problem were also performed to study their influence on the behavior under indentation and the bending capacity of the composite structure.


Author(s):  
Asieh Khosravanian ◽  
Mohammad Rahmanimanesh ◽  
Parviz Keshavarzi

The Social Spider Algorithm (SSA) was introduced based on the information-sharing foraging strategy of spiders to solve the continuous optimization problems. SSA was shown to have better performance than the other state-of-the-art meta-heuristic algorithms in terms of best-achieved fitness values, scalability, reliability, and convergence speed. By preserving all strengths and outstanding performance of SSA, we propose a novel algorithm named Discrete Social Spider Algorithm (DSSA), for solving discrete optimization problems by making some modifications to the calculation of distance function, construction of follow position, the movement method, and the fitness function of the original SSA. DSSA is employed to solve the symmetric and asymmetric traveling salesman problems. To prove the effectiveness of DSSA, TSPLIB benchmarks are used, and the results have been compared to the results obtained by six different optimization methods: discrete bat algorithm (IBA), genetic algorithm (GA), an island-based distributed genetic algorithm (IDGA), evolutionary simulated annealing (ESA), discrete imperialist competitive algorithm (DICA) and a discrete firefly algorithm (DFA). The simulation results demonstrate that DSSA outperforms the other techniques. The experimental results show that our method is better than other evolutionary algorithms for solving the TSP problems. DSSA can also be used for any other discrete optimization problem, such as routing problems.


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