• Journal of Aerospace System Engineering
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• v.4 no.3
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• pp.1-5
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• 2010

Understanding the crushing behaviour of aluminum honeycombs under dynamic loading is useful for crash simulations of vehicles and for design of impacting energy absorbers. In the study of honeycomb crushing under quasi-static, dynamic loading, the most important parameter is crush strength. Crush strength is indicated to energy absorption characteristic of aluminum honeycomb. In this study, Using Finite Element Analysis carried out crush strength of hexagonal aluminum honeycomb then the results was compared with Quasi-static test. Consequently, Crush strength is different in quasi-static loading and dynamic loading about 16%.

• Geomechanics and Engineering
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• v.17 no.4
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• pp.405-411
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• 2019

A significant influence of the particle size distribution on the resilient behaviour of granular aggregates was usually observed in laboratory tests. However, the mechanisms underlying this phenomenon were rarely reached. In this study, a mechanistic model considering particle breakage is proposed. It is found to be the combined effects of the coefficient of uniformity and the size range between maximum and minimum particle sizes that influences the resilient modulus of granular aggregates. The resilient modulus is found to undergo reduction with evolution of particle breakage by shifting the initial particle size distribution to a broader one.

• Earthquakes and Structures
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• v.17 no.3
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• pp.283-295
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• 2019

During the seismic performance assessment of existing buildings, staircases are generally not taken into account as structural members but as dead load. Staircases, as secondary structural members, not only serve for connecting successive floors but also provide considerable amount of strength and stiffness to the building which can modify its seismic behaviour considerably. In this parametric study, the influence of staircases on the seismic response of substandard RC frame buildings which differ in number of storey and span, presence of staircase and its position has been examined. Modal Analyses and bi-directional Non-Linear Time History Analyses (NLTHA) were conducted to compare several engineering demand parameters (EDPs) such as inter-storey drift ratio (ISDR), floor accelerations, modal properties, member shear forces and plastic hinge distribution. Additionally, short column effect, variation in shear forces of columns that are attached to the staircase slab, failure and deformation in staircase models have also been investigated. As the staircase was considered in the analytical model, a different damage pattern can be developed especially in the structural components close to staircase.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.1-12
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• 2004

Due to the 1989 Loma Prieta, 1995 Hyogoken Nambu earthquakes, etc, a number of bridge columns  were collapsed in flexure-shear failures as a consequence of the premature termination of the column longitudinal reinforcement. Nevertheless, previous researches for the performance of bridge columns were concentrated on the flexural failure mode. It is well understood that the seismic behaviour of RC bridge piers was dependent on the performance of the plastic hinge of RC bridge piers, the ductility of which was desirable to be computed on the basis of the curvature. Experimental investigation was made to evaluate the variation of the curvature of the plastic hinge  region for the seismic performance of earthquake-damaged RC columns in flexure-shear failure mode. Seven test specimens in the aspect ratio of 2.5 were made with test parameters: confinement ratios, lap splices, and retrofitting FRP materials. They were damaged under series of artificial earthquakes that could be compatible in Korean peninsula. Directly after the pseudo-dynamic test, damaged columns were retested under inelastic reversal cyclic loading under a constant axial load, $P=0.1f_{ck}A_g$. Residual seismic capacity of damaged specimens was evaluated by analzying the moment-curvature hysteresis and the curvature ductility. Test results show that the biggest curvature was developed around 15cm above the footing, which induced the column failure. It was observed that RC bridge specimens with lap-spliced longitudinal steels appeared to fail at low curvature ductility but significant improvement was made in the curvature ductility of RC specimens with FRP straps wrapped around the plastic hinge region. Based on the experimental variation of the curvature of RC specimens, new equivalent length of the plastic hinge region was proposed by considering the lateral confinement in this study. The analytical and experimental relationship between the displacement and the curvature ductility were compared based on this proposal, which gave excellent result.

• Journal of the Korean Society of Industry Convergence
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• v.15 no.1
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• pp.21-27
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• 2012

Decomposed granite soils are in a wide range of conditions depending on the degrees of weathering. This paper is intended to examine laboratory tests such as consolidation tests and conventional triaxial compression tests conducted in order to find out the mechanical properties of Cheongju granite soil. Along with the foregoing, the results of basic physical tests conducted in order to grasp the physical properties of Cheongju granite soil were described and based on the results, methods to calculate the mechanical parameters of numerical approaches using Lade's double surface work-hardening constitutive model were examined. Finally, it is intended to explain the stress properties of Cheongju granite soil used as a geotechnical material based on its shear behavior and critical state concept using the results of isotropic consolidation tests and triaxial compression tests. As a conclusion, it can be seen that in the relationship between confining stress and maximum deviator stress, the slope is maintained at a constant value of 2.95. In the drained CTC test, maximum deviator stress generally existed in a range of axial strain of 6~8% and larger dilatancy phenomena appeared when confining stress was smaller. Finally, based on the results of the CTC tests on Cheongju granite soil, although axial strain, deviator stress and pore water pressure showed mechanical properties similar to those of overconsolidated soil, Cheongju granite soil showed behavior similar to that of normally consolidated soil in terms of volumetric strain.

• Journal of Korean Society of Steel Construction
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• v.27 no.4
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• pp.359-370
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• 2015

This paper presents the experimental results for the interfacial bond behaviour between AFRP strip and steel members. The objective of this paper is to examine the interfacial behavior and to evaluate the interfacial bond stress between Aramid FRP strips and steel plates. The test variables were bond length and AFRP thickness. 18 specimens were fabricated and one-face shear type bond tests were conducted in this study. There were two types of failure mode which were debonding and delamination between AFRP strip and steel plates. From the test, the load was increased with the increasing of bond length and AFRP thickness, which was observed that maximum increase of 63 and 86% were also achieved in load with the increasing of bond length and AFRP thickness, respectively. Finally, bond and slip characteristics had the elastic bond-slip model and it was observed that bond strength and fracture energy were not affected by bond length and AFRP thickness.

• Steel and Composite Structures
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• v.18 no.6
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• pp.1423-1450
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• 2015

The paper presents the details and results of an experimental study on bolted end-plate joints of industrial type steel building frames. The investigated joints are commonly used in Lindab-Astron industrial buildings and are optimized for manufacturing, erection and durability. The aim of the research was to provide an experimental background for the design model development by studying load-bearing capacity of joints, bolt force distribution, and end-plate deformations. Because of the special joint details, (i.e., joints with four bolts in one bolt-row and HammerHead arrangements), the Eurocode 3 standardized component model had to be improved and extended. The experimental programme included six different end-plate and bolt arrangements and covered sixteen specimens. The steel grade of test specimens was S355, the bolt diameter M20, whereas the bolt grade was 8.8 and 10.9 for the two series. The end-plate thickness varied between 12 mm and 24 mm. The specimens were investigated under pure bending conditions using a four-point-bending test arrangement. In all tests the typical displacements and the bolt force distribution were measured. The end-plate plastic deformations were measured after the tests by an automatic measuring device. The measured data were presented and evaluated by the moment-bolt-row force and moment-distance from centre of compression diagrams and by the deformed end-plate surfaces. From the results the typical failure modes and the joint behaviour were specified and presented. Furthermore the influence of the end-plate thickness and the pretension of the bolts on the behaviour of bolted joints were analysed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.89-93
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• 2008

Stiffened panels are basic strength members which have been used widely in a vessel or an offshore. They have been used often a deck, a side and a bottom structure of ship and have a number of one sided stiffener in either one or both directions called grillage. Their buckling and plastic collapse become damaged reason of the hull girder so it needs to investigate accurately buckling and ultimate strength of stiffened panels. In the present paper, using the ANSYS, a commercial finite element analysis code, we conducted the evaluation regarding buckling and post-buckling behaviour of stiffened panels, and analyzed stiffener's web height change, considering the effect of lateral pressure load against compression ultimate strength.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.4
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• pp.567-578
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• 2002

The main purpose of this study is to investigate the dynamic behaviour of containment building in nuclear power plant excited by aircraft impact loading using a lower order 8-node solid element. The yield and failure surfaces for concrete material model is formulated on the basis of Drucker-Prager yield criteria and are assumed to be varied by taking account of the visco-plastic energy dissipation. The standard 8-node solid element has prone to exhibit the element deficiencies and the so-called B bar method proposed by Hughes is therefore adopted in this study. The implicit Newmark method is adopted to ensure the numerical stability during the analysis. Finally, the effect of different levels of cracking strain and several types of aircraft loading are examined on the dynamic behaviour of containment building and the results are quantitatively summarized as a future benchmark.

• Steel and Composite Structures
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• v.10 no.3
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• pp.207-222
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• 2010

Fire incident in buildings is common, so the fire safety design of the framed structure is imperative, especially for the unprotected or partly protected bare steel frames. However, software for structural fire analysis is not widely available. As a result, the performance-based structural fire design is urged on the basis of using user-friendly and conventional nonlinear computer analysis programs so that engineers do not need to acquire new structural analysis software for structural fire analysis and design. The tool is desired to have the capacity of simulating the different fire scenarios and associated detrimental effects efficiently, which includes second-order P-D and P-d effects and material yielding. Also the nonlinear behaviour of large-scale structure becomes complicated when under fire, and thus its simulation relies on an efficient and effective numerical analysis to cope with intricate nonlinear effects due to fire. To this end, the present fire study utilizes a second-order elastic/plastic analysis software NIDA to predict structural behaviour of bare steel framed structures at elevated temperatures. This fire study considers thermal expansion and material degradation due to heating. Degradation of material strength with increasing temperature is included by a set of temperature-stress-strain curves according to BS5950 Part 8 mainly, which implicitly allows for creep deformation. This finite element stiffness formulation of beam-column elements is derived from the fifth-order PEP element which facilitates the computer modeling by one member per element. The Newton-Raphson method is used in the nonlinear solution procedure in order to trace the nonlinear equilibrium path at specified elevated temperatures. Several numerical and experimental verifications of framed structures are presented and compared against solutions in literature. The proposed method permits engineers to adopt the performance-based structural fire analysis and design using typical second-order nonlinear structural analysis software.