Dissertation > Industrial Technology > Building Science > Building structure > Metal structures > Various types of steel > Light steel

Numerical Analysis on Dynamic Response and Failure Modes of Light-weiglit Steel Columns under Blast Loads

Author LiuLei
Tutor YanShi
School Shenyang University of construction
Course Disaster Prevention and Reduction Engineering and Protective Engineering
Keywords Blast loading Light-weight steel columns Dynamic response Failure mode Finite element method (FEM)
CLC TU392.5
Type Master's thesis
Year 2012
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As the increasing of light-weight steels in the application of industrial and civilconstruction and benefits of itself, in particular, they are widely used in large public buildings.Once being subjected to an accidental explosion load, they will not only bring casualties andproperty losses, but also seriously affect the public image. The whole building may generatecollapse caused by the destruction of the main force components like beams and columns.Therefore, the researches on dynamic response and failure mode analysis of the light-weightsteel columns under blasting loading become very concerned and the need for further study.So far, the numerical calculation method can be seen as aids of theoretical andexperimental studies, and it has become a basic scientific method that is independent oftheoretical and experimental methods. Since the1960s, explosion mechanics workers in allcountries, especially represented by the three major U.S. defense labs, have performed a lot ofexplosion mechanics numerical calculations, and have successfully calculated so many complexproblems that cannot be calculated before, making the numerical simulation techniques to playan irreplaceable role in the analysis of such issues.In this paper, the dynamic response and failure process for two types of light-weight steelcolumns under blast loading were numerically analyzed by use of LS-DYNA software, and asimplified method for calculating such dynamic displacement was proposed. The main workswere as following:(1)The rationality of the numerical calculation method in the research was validated inthe paper by compare to examples in a foreign paper.(2)Theory analysis of dynamic response for light-weight steel columns under blastloading was performed. Explosion was involving a large number of nonlinear transientdynamics problems, and the core of the mathematical model was a set of nonlinear partialdifferential equations. Based on the mainly nature of the problems, the theoretical solution ofthe dynamic response for the continuous systems under blast loading was derived.(3)The main influencing factors on the dynamic response of columns with Icross-section were numerically discussed. The affecting law on the displacement and stressresponses by the boundary condition, the axial compression ratio and “scaled distances” of theexplosion was analyzed. Three typical failure modes which were flexural failure, shear failureand combination of the flexure and shear were summarized by defining failure criteria. Theproposed failure modes can be used as a reference for the anti-blast design and construction forthe engineering structures.(4)The concrete infilled rectangular steel tube (CIRST) column was numericallyanalyzed in the paper to investigate the dynamic responses and failure modes under the blast loading, focusing on analysis of dynamic response of different constraints situations underblasting loads. The failure modes were consistent with the theoretical calculations. The resultsshowed that the CIRST column has the excellent ductility and blast resistance(5)The dynamic factors were introduced to simplify the calculation method of thedisplacement of light-weight steel columns under blasts loads. To eliminate the effect of columndimensions, boundary conditions, etc, on the proposed dynamic factors, three curves fordifferent slenderness ratios were drawn, and middle displacement values of light-weight steelcolumns under blast loading can be easily estimated by using the proposed curves in actualprojects.(6)Finally, all the work done in the paper were summarized, and some problems whichneed to be researched in the future were put forward.

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