• Steel and Composite Structures
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• v.38 no.3
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• pp.305-317
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• 2021

The mechanical behavior of the outer square inner circular concrete-filled dual steel tubular (SCCFT) stub columns under axial compression is investigated by means of experimental research, numerical analysis and theoretical investigation. Parameters such as diameter ratio, concrete strength and steel ratio were discussed to identify their influence on the mechanical properties of SCCFT short columns on the basis of the experimental investigation of seven SCCFT short columns. By establishing a finite element model, nonlinear analysis was performed to discuss the longitudinal and transverse stress of the dual steel tubes. The longitudinal stress characteristics of the core and sandwich concrete were also analyzed. Furthermore, the failure sequence was illustrated and the reasonable cross-section composition of SCCFT stub column was proposed. A formula to predict the axial load capacity of SCCFT stub column was advanced and verified by the results from experiment and the finite element.

• Geomechanics and Engineering
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• v.8 no.2
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• pp.283-303
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• 2015

To research and analyze the differential settlements of foundations specifically, site investigations of existing railways and metro were firstly carried out. Then, the centrifugal test was used to observe differential settlements in different position between foundations on the basis of investigation. The theoretical model was established according to the stress diffusion method and Fourier method to establish an analytical solution of embankment differential settlement between different foundations. Finally, theoretical values and experimental values were analyzed comparatively. The research results show that both in horizontal and vertical directions, evident differential settlement exists in a limited area on both sides of the vertical interface between different foundations. The foundation with larger elastic modulus can transfer more additional stress and cause relatively less settlement. Differential settlement value decreases as the distance to vertical interface decreases. In the vertical direction of foundation, mass differential settlement also exists on both sides of the vertical interface and foundation with larger elastic modulus can transfer more additional stress. With the increase of relative modulus of different foundations, foundation with lower elastic modulus has larger settlement. Meanwhile, differential settlement is more obvious. The main error sources in theoretical and experimental values include: (a) different load form; (b) foundation characteristics differences; (c) modulus conversion; (d) effect of soil internal friction.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1631-1633
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• 2009

• Fire Science and Engineering
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• v.22 no.5
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• pp.105-111
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• 2008

Improvement of fire investigation system is required to supplement problem that can happen after product liability law enforcement of our country. This treatise searches special quality of inside and outside of the country fire investigation that was enforced present with theoretical background of manufacture water responsibility law and compared. And is based and grasped objective and hangup in police fire investigation, fire fighting fire investigation, engine fire investigation of private fire judgment. By improvement way accordingly first, proposed fire emotion connection studies and establishment and connoisseurship qualification system establishment etc. in the common people private fire diet, judgment, analysis company's necessity second, fire fighting of fire investigation system, police's member anger third, college.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.832-836
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• 2003

To extend the knowledge of triple bonding between group 6 transition metal and heavier group 14 elements, the structural and bonding aspects of ($η^5-C_5H_5$)$(CO)_2$M≡ER (M = Cr, Mo, W; E = Si, Ge, Sn, Pb) are investigated by hybrid density functional calculations at the B3PW91 level. Substituent effects are also investigated with R = H, Me, $SiH_3$, Ph, $C_6H_3-2,6-Ph_2$, $C_6H_3-2,6-(C_6H_2-2,4,6-Me_3)_2$, and $C_6H_3-2,6-(C_6H_2-2,4,6- iPr_3)_2$.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.44
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• pp.181-210
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• 2009

This paper discusses global expansion and global strategies of shipping firms. Acknowledging the lack of research on global expansion by freight transport companies, this paper employs the resource-focused model, and explores "why shipping companies emerge" and "why the strategic behaviour of shipping companies is different in the global market". Despite there being a plethora of theoretical and empirical studies on the international operations of business organisations, it is acknowledged that researchers have largely neglected the issues regarding the international expansion within the freight transport industry. Identifying the general lack of contemporary studies concerning the international behaviour of shipping firms, this study addresses the important gap in our knowledge in the theoretical manner. The theoretical analysis suggests that the shipping company's internal resources can be a real reason for the international market participation.

• Advances in aircraft and spacecraft science
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• v.1 no.2
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• pp.177-196
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• 2014

A theoretical exploration for determining the characteristic length of the cohesive zone for a double cantilever beam (DCB) specimen under mode I loading was conducted. Two traction-separation laws were studied: (i) a law with only a linear elastic stage from zero to full traction strength; and (ii) a bilinear traction law illustrating a progressive softening stage. Two analytical solutions were derived for the first law, which fit well into two existing solution groups. A transcendental equation was derived for the bilinear traction law, and a graphical method was presented to identify the resultant cohesive zone length. The study using the bilinear traction law enabled the theoretical investigation of the individual effects of cohesive law parameters (i.e., strength, stiffness, and fracture energy) on the cohesive zone length. Correlations between the theoretical and finite element (FE) results were assessed. Effects of traction law parameters on the cohesive zone length were discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.359-364
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• 1998

The effects of boundary conditions on natural frequencies for the ring stiffened composite cylindrical shells are investigated by theoretical method. The Love's thin shell theory and the discrete stiffener theory with beam functions in the Ritz procedure are used to derive the frequency equation. Five different boundary conditions such as clamped-clamped, simply supported-simply supported, free-free, clamped-free, clamped-simply supported are considered in this study. Also, the experimental investigation is presented to validate the theoretical results.

• Tribology and Lubricants
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• v.3 no.1
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• pp.31-38
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• 1987

This paper describes a theoretical model for the prediction of the spacing profile between a flexible magnetic tape tensioned around a rotating drum and a protruding head mounted on the drum. The analysis is based on the coupled equations controlling the elastic deformation of the tape and the hydrodynamic pressure of the gas film. Some results are presented for a cylindrical head.

• Fire Science and Engineering
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• v.25 no.3
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• pp.42-50
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• 2011

To foster fire investigation professionals and expand career opportunities for graduates of fire science majors, it is extremely important to expand and reorganize courses which are related to fire investigation. Only 30 percent of universities have fire investigation related courses, and the courses only offer theoretical materials. As a result, it has a great limitation to teach essential knowledge which is required at a fire scene. This study suggests to classify fire investigation-related-courses in to fire investigation course and fire identification course. In addition, the study proposes ways to standardize curricula which enables students to acquire Certified Fire and Explosion Investigator (CFEI).