Current Issue : July - September Volume : 2016 Issue Number : 3 Articles : 4 Articles
This paper addresses a structure design competition based on topology optimization and 3D Printing, and\nproposes an experimental approach to efficiently and quickly measure the mechanical performance of the structures\ndesigned using topology optimization. Since the topology optimized structure designs are prone to be geometrically\ncomplex, it is extremely inconvenient to fabricate these designs with traditional machining. In this study, we not only\nfabricated the topology optimized structure designs using one kind of 3D Printing technology known as stereolithography\n(SLA), but also tested the mechanical performance of the produced prototype parts. The finite element method\nis used to analyze the structure responses, and the consistent results of the numerical simulations and structure\nexperiments prove the validity of this new structure testing approach. This new approach will not only provide a rapid\naccess to topology optimized structure designs verifying, but also cut the turnaround time of structure design\nsignificantly....
Steel built-up batten columns are common\ntypes of columns in Iran and some other parts of the world.\nThey are economic and have acceptable performance due\nto gravity loads. Although several researches have been\nconducted on the behavior of the batten columns under\naxial loads, there are few available articles about their\nseismic performance. Experience of the past earthquakes,\nparticularly the 2003 Bam earthquake in Iran, revealed that\nthese structural members are seismically vulnerable. Thus,\ninvestigation on seismic performance of steel batten columns\ndue to seismic loads and providing a method for\nretrofitting them are important task in seismic-prone areas.\nThis study aims to investigate the behavior of concretefilled\nbatten columns due to combined axial and lateral\nloads. To this end, nonlinear static analyses were performed\nusing ANSYS software. Herein, the behaviors of\nthe steel batten columns with and without concrete core\nwere compared. The results of this study showed that\nconcrete-filled steel batten columns, particularly those filled\nwith high-strength concrete, may cause significant\nincreases in energy absorption and capacity of the columns.\nFurthermore, concrete core may improve post-buckling\nbehavior of steel batten columns....
During earthquake, reinforced concrete walls show complicated post-yield behavior varying with shear span-to-depth\nratio, re-bar detail, and loading condition. In the present study, a macro-model for the nonlinear analysis of multi-story wall\nstructures was developed. To conveniently describe the coupled flexure-compression and shear responses, a reinforced concrete\nwall was idealized with longitudinal and diagonal uniaxial elements. Simplified cyclic material models were used to describe the\ncyclic behavior of concrete and re-bars. For verification, the proposed method was applied to various existing test specimens of\nisolated and coupled walls. The results showed that the predictions agreed well with the test results including the load-carrying\ncapacity, deformation capacity, and failure mode. Further the proposed model was applied to an existing wall structure tested on a\nshaking table. Three-dimensional nonlinear time history analyses using the proposed model were performed for the test specimen.\nThe time history responses of the proposed method agreed with the test results including the lateral displacements and base shear....
Axially loaded reinforced concrete columns are hardly exist in practice due to the development of some bending\nmoments. These moments could be produced by gravity loads or the lateral loads. First, the current paper presents a detailed\nanalysis on the overall structural behavior of 15 eccentrically loaded columns as well as one concentrically loaded control one.\nColumns bent in either single curvature or double curvature modes are tested experimentally up to failure under the effect of\ndifferent end eccentricities combinations. Three end eccentricities ratio were studied, namely, 0.1b, 0.3b and 0.5b, where b is the\ncolumn width. Second, an expression correlated the decay in the normalized axial capacity of the column and the acting end\neccentricities was developed based on the experimental results and then verified against the available formula. Third, based on\nthe equivalent column concept, the equivalent pin-ended columns were obtained for columns bent in either single or double\ncurvature modes. And then, the effect of end eccentricity ratio was correlated to the equivalent column length. Finally, a\nsimplified design procedure was proposed for eccentrically loaded braced column by transferring it to an equivalent axially\nloaded pin-ended slender column. The results of the proposed design procedure showed comparable results against the results of\nthe ACI 318-14 code....
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