The Experts below are selected from a list of 1725 Experts worldwide ranked by ideXlab platform
Michael Richard Bambach - One of the best experts on this subject based on the ideXlab platform.
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Axial Capacity and crushing behavior of metal fiber square tubes steel stainless steel and aluminum with cfrp
Composites Part B-engineering, 2010Co-Authors: Michael Richard BambachAbstract:Abstract Composite metal-carbon fiber reinforced polymer (CFRP) tubes combine the benefits of the high strength to weight ratio of the fiber/resin composite and the stable, ductile plastic collapse mechanism of the metal, to form a composite tube with high strength and energy absorption capability. This paper investigates the Axial Capacity and crushing behavior of square hollow section (SHS) tubes composed of composite steel-CFRP, stainless steel-CFRP and aluminum-CFRP. Experiments of tubes with different metal SHS geometries and two different matrix layouts of carbon fibers are described, and a general theory to predict the compression buckling, Axial Capacity, Axial collapse and mean crush load of metal–fiber square tubes is developed and validated against the experimental results. It is shown that carbon fiber may be successfully externally bonded to metal SHS, and such application may be provided to improve the performance of existing structures, or to design new structures with enhanced strength-weight and energy absorption-weight ratios. Comparisons are made between the performance of the different types of metals, SHS geometries and carbon fiber matrix layouts.
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Axial Capacity and crushing behavior of metal–fiber square tubes – Steel, stainless steel and aluminum with CFRP
Composites Part B-engineering, 2010Co-Authors: Michael Richard BambachAbstract:Abstract Composite metal-carbon fiber reinforced polymer (CFRP) tubes combine the benefits of the high strength to weight ratio of the fiber/resin composite and the stable, ductile plastic collapse mechanism of the metal, to form a composite tube with high strength and energy absorption capability. This paper investigates the Axial Capacity and crushing behavior of square hollow section (SHS) tubes composed of composite steel-CFRP, stainless steel-CFRP and aluminum-CFRP. Experiments of tubes with different metal SHS geometries and two different matrix layouts of carbon fibers are described, and a general theory to predict the compression buckling, Axial Capacity, Axial collapse and mean crush load of metal–fiber square tubes is developed and validated against the experimental results. It is shown that carbon fiber may be successfully externally bonded to metal SHS, and such application may be provided to improve the performance of existing structures, or to design new structures with enhanced strength-weight and energy absorption-weight ratios. Comparisons are made between the performance of the different types of metals, SHS geometries and carbon fiber matrix layouts.
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Axial Capacity and crushing of thin-walled metal, fibre–epoxy and composite metal–fibre tubes
Thin-walled Structures, 2010Co-Authors: Michael Richard BambachAbstract:Abstract Recent investigations of square hollow section (SHS) metal tubes with externally bonded carbon fibres have shown significant increases in the Axial Capacity and mean crushing load, compared with the metal SHS. The composite metal–fibre tubes employed carbon fibre reinforced polymer (CFRP) matrix layouts of two and four layers of carbon fibres. In this paper the same sized two and four layer CFRP SHS were manufactured independent of the metal SHS, and the Axial Capacity and crushing behaviour were determined experimentally. Four different tube sizes were tested, resulting in tube width to thickness ratios between 32 and 144. A photogrammetry system was employed to accurately determine the buckling and post-buckling behaviour. It is shown that the Capacity and mean crush load of the composite metal–CFRP SHS exceed the sum of those for the individual metal SHS and CFRP SHS, by up to 1.8 times. This composite action results from the bond between the metal and the carbon fibres, and the mechanics with respect to buckling, Capacity and crushing is discussed. The strength of metal, composite metal–CFRP and CFRP tube walls are determined using the effective width approach, and are shown to compare well with the experimental results.
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Axial Capacity and crushing of thin walled metal fibre epoxy and composite metal fibre tubes
Thin-walled Structures, 2010Co-Authors: Michael Richard BambachAbstract:Abstract Recent investigations of square hollow section (SHS) metal tubes with externally bonded carbon fibres have shown significant increases in the Axial Capacity and mean crushing load, compared with the metal SHS. The composite metal–fibre tubes employed carbon fibre reinforced polymer (CFRP) matrix layouts of two and four layers of carbon fibres. In this paper the same sized two and four layer CFRP SHS were manufactured independent of the metal SHS, and the Axial Capacity and crushing behaviour were determined experimentally. Four different tube sizes were tested, resulting in tube width to thickness ratios between 32 and 144. A photogrammetry system was employed to accurately determine the buckling and post-buckling behaviour. It is shown that the Capacity and mean crush load of the composite metal–CFRP SHS exceed the sum of those for the individual metal SHS and CFRP SHS, by up to 1.8 times. This composite action results from the bond between the metal and the carbon fibres, and the mechanics with respect to buckling, Capacity and crushing is discussed. The strength of metal, composite metal–CFRP and CFRP tube walls are determined using the effective width approach, and are shown to compare well with the experimental results.
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Axial Capacity and design of thin walled steel shs strengthened with cfrp
Thin-walled Structures, 2009Co-Authors: Michael Richard Bambach, Hussein Haji Jama, Mohamed ElchalakaniAbstract:Abstract Carbon fibre reinforced polymer (CFRP) strengthening of structures has been gaining increasing interest, traditionally applied to concrete structures, and more recently applied to steel structures. This paper describes 20 experiments on short, Axially compressed square hollow sections (SHS) cold-formed from G450 steel and strengthened with externally bonded CFRP. The SHS were fabricated by spot-welding and had plate width-to-thickness ratios between 42 and 120, resulting in plate slenderness ratios between 1.1 and 3.2. Two different matrix layouts of the CFRP were investigated. It is shown that the application of CFRP to slender sections delays local buckling and subsequently results in significant increases in elastic buckling stress, Axial Capacity and strength-to-weight ratio of the compression members. The experiments are an extension of a previous study [Bambach MR, Elchalakani M. Plastic mechanism analysis of steel SHS strengthened with CFRP under large Axial deformation. Thin-Walled Structures 2007;45(2):159–70] in which 25 commercially produced SHS with plate slenderness values between 0.3 and 1.6 were strengthened with CFRP in the same manner. A design method is developed whereby the theoretical elastic buckling stress of the composite steel–CFRP sections is used to determine the Axial Capacity, and is shown to compare well with the 45 test results. A reliability analysis shows the method to be suitable for design.
S M Kulkarni - One of the best experts on this subject based on the ideXlab platform.
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Axial Capacity of rectangular concrete filled steel tube columns doe approach
Construction and Building Materials, 2010Co-Authors: Manojkumar V Chitawadagi, Mattur C Narasimhan, S M KulkarniAbstract:Abstract This paper presents the effect of change in wall thickness of the steel tube ( t ), strength of in-filled concrete ( f cu ), cross-sectional area of the steel tube ( A ) and length of the tube ( L ) on ultimate Axial load and Axial shortening at ultimate point of rectangular concrete-filled steel tubes (CFT). Taguchi’s approach with an L9 orthogonal array is used to reduce the number of experiments. With the help of initial experiments, linear regression models are developed to predict the ultimate Axial load and the Axial shortening at ultimate point. A total of 243 rectangular CFT samples are tested to verify the accuracy of these models at three factors with three levels. The experimental results are analyzed using Analysis Of Variance to investigate the most influencing factor on strength and Axial shortening of CFT samples. Comparisons are made with predicted column strengths using the existing design codes, AISC–LRFD-1994 and EC4-1994.
Manojkumar V Chitawadagi - One of the best experts on this subject based on the ideXlab platform.
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Axial Capacity of rectangular concrete filled steel tube columns doe approach
Construction and Building Materials, 2010Co-Authors: Manojkumar V Chitawadagi, Mattur C Narasimhan, S M KulkarniAbstract:Abstract This paper presents the effect of change in wall thickness of the steel tube ( t ), strength of in-filled concrete ( f cu ), cross-sectional area of the steel tube ( A ) and length of the tube ( L ) on ultimate Axial load and Axial shortening at ultimate point of rectangular concrete-filled steel tubes (CFT). Taguchi’s approach with an L9 orthogonal array is used to reduce the number of experiments. With the help of initial experiments, linear regression models are developed to predict the ultimate Axial load and the Axial shortening at ultimate point. A total of 243 rectangular CFT samples are tested to verify the accuracy of these models at three factors with three levels. The experimental results are analyzed using Analysis Of Variance to investigate the most influencing factor on strength and Axial shortening of CFT samples. Comparisons are made with predicted column strengths using the existing design codes, AISC–LRFD-1994 and EC4-1994.
Hamid Nikraz - One of the best experts on this subject based on the ideXlab platform.
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predicting Axial Capacity of driven piles in cohesive soils using intelligent computing
Engineering Applications of Artificial Intelligence, 2012Co-Authors: Iyad Alkroosh, Hamid NikrazAbstract:An accurate prediction of pile Capacity under Axial loads is necessary for the design. This paper presents the development of a new model to predict Axial Capacity of pile foundations driven into cohesive soils. Gene expression programming technique (GEP) has been utilized for this purpose. The data used for development of the GEP model is collected from the literature and comprise a series of in-situ driven piles load tests as well as cone penetration test (CPT) results. The data are divided into two subsets: training set for model calibration and independent validation set for model verification. Predictions from the GEP model are compared with experimental data and with predictions of number of currently adopted CPT-based methods. The results have demonstrated that the GEP model performs well with coefficient of correlation, mean and probability density at 50% equivalent to 0.94, 0.96 and 1.01, respectively, indicating that the proposed model predicts pile Capacity accurately.
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Correlation of Pile Axial Capacity and CPT Data Using Gene Expression Programming
Geotechnical and Geological Engineering, 2011Co-Authors: Iyad Alkroosh, Hamid NikrazAbstract:Numerous methods have been proposed to assess the Axial Capacity of pile foundations. Most of the methods have limitations and therefore cannot provide consistent and accurate evaluation of pile Capacity. However, in many situations, the methods that correlate cone penetration test (CPT) data and pile Capacity have shown to provide better results, because the CPT results provide more reliable soil properties. In an attempt to obtain more accurate correlation of CPT data with Axial pile Capacity, gene expression programming (GEP) technique is used in this study. The GEP is a relatively new artificial intelligent computational technique that has been recently used with success in the field of engineering. Three GEP models have been developed, one for bored piles and two other models for driven piles (a model for each of concrete and steel piles). The data used for developing the GEP models are collected from the literature and comprise a total of 50 bored pile load tests and 58 driven pile load tests (28 concrete pile load tests and 30 steel pile load tests) as well as CPT data. For each GEP model, the data are divided into a training set for model calibration and an independent validation set for model verification. The performances of the GEP models are evaluated by comparing their results with experimental data and the robustness of each model is investigated via sensitivity analyses. The performances of the GEP models are evaluated further by comparing their results with the results of number of currently used CPT-based methods. Statistical analyses are used for the comparison. The results indicate that the GEP models are robust and perform well.
Brahim Benmokrane - One of the best experts on this subject based on the ideXlab platform.
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Axial Capacity of circular concrete columns reinforced with gfrp bars and spirals
Journal of Composites for Construction, 2014Co-Authors: Mohammad Z Afifi, Hamdy M Mohamed, Brahim BenmokraneAbstract:AbstractSeveral codes and design guidelines are now available for the design of concrete structures reinforced with fiber-reinforced polymer (FRP) bars under flexural and shear loads. Yet, because of a lack of research, North American codes and design guidelines do not recommend using FRP bars as longitudinal reinforcement in columns to resist compressive stresses. This paper reports on 12 full-scale circular reinforced concrete (RC) columns that were tested under concentric Axial loads. The columns were reinforced with longitudinal glass FRP (GFRP) bars and newly developed GFRP spirals. The 300-mm diameter columns were designed according to code requirements. The test parameters included reinforcement type (GFRP versus steel); longitudinal FRP reinforcement ratio; and the volumetric ratios, diameters, and spacing of spiral reinforcement. The test results indicated that the GFRP and steel RC columns behaved in a similar manner. The average load carried by the longitudinal GFRP bars ranged between 5% and 1...
