• Structural Engineering and Mechanics
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• v.77 no.1
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• pp.89-102
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• 2021

Rapid construction of prefabricated bridges requires minimizing the field work of precast members and ensuring structural stability and constructability. In this study, we conducted experimental and analytical investigations of transverse joints of prefabricated T-girder bridge superstructures to verify the flexural performance and serviceability. In addition, we conducted parametric studies to identify the joint parameters. The results showed that both the segmented and continuous specimens satisfied the ultimate flexural strength criterion, and the segmented specimen exhibited unified behavior, with the flexural strength corresponding to that of the continuous specimen. The segmented specimens exhibited elastic behavior under service load conditions, and the maximum crack width satisfied the acceptance criteria. The reliability of the finite element model of the joint was verified, and parametric analysis of the convexity of the joint section and the compressive strength of the filler concrete showed that the minimum deflection and crack width occurred at a specific angle. As the strength of the filler concrete increased, the deflection and crack width decreased. However, we confirmed that the reduction in the crack width was hardly observed above a specific strength. Therefore, a design suitable for prefabricated bridges and accelerated construction can be achieved by improving the joint specifications based on the required criteria.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.772-785
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• 2021

Container ships has a transverse section in the form of an open profile, making it very sensitive to torsion phenomena. To minimize this effect, a structure known as a torsion box exists, which is subject to high stresses influenced by the fatigue phenomenon and the existence of cut-outs, for the passage of the longitudinal stiffeners, acting as stress concentrators. The aim of this study is to propose a two-stage design methodology to aid designers in satisfying the structural requirements and contribute with to a better understanding of the considered structure. The transverse webs of a torsional box structure are examined by comparing different cut-out geometries from numerical models with different regular load conditions to obtain the variables of the fatigue safety factor through linear regression models. The most appropriate geometry of the torsion box is established in terms of minimum weight, from nonlinear multivariable optimization models.

• International Journal of Highway Engineering
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• v.19 no.1
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• pp.63-72
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• 2017

PURPOSES : The purpose of this study is to investigate the fundamental behaviors such as stresses and deflections of the middle slab in a double-deck tunnel for the development of a middle slab design guide. METHODS : The middle slab has been divided into the following three different sections as according to its structural differences: the normal section, expansion joint section, and emergency passageway section. The normal section of middle slab represents the slab supported by brackets installed continuously along the longitudinal direction of tunnel lining. The expansion joint section refers to a discontinuity of middle slab due to the existence of a transverse expansion joint. The emergency passageway section has an empty rectangular space in the middle slab that acts as an exit in an emergency. The finite element analysis models of these three sections of middle slab have been developed to analyze their respective behaviors. RESULTS : The stresses and deflections of middle slab at the three different sections decrease as the slab thickness increases. The emergency passageway section yields the largest stresses and deflections, with the normal section yielding the smallest. CONCLUSIONS : The stress concentrations at the corners of the passageway rectangular space can be reduced by creating hunch areas at the corners. The stresses and deflections in the emergency passageway section can be significantly decreased by attaching beams under the middle slab in the passageway area.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2638-2641
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• 2007

The magnetohydrodynamic(MHD) pressure drop along a liquid sodium flow was measured in a rectangular duct under a transverse magnetic field. The test section was made of a 3 mm thick stainless steel SUS304 with a $74{\times}5mm^2$ rectangular flow channel. The range of experimental parameters was roughly B=0${\sim}$0.18T and U=0${\sim}$0.9m/s at around $200^{\circ}C$. The differential pressure was measured by a diaphragm seal-type pressure transmitter filled with a high temperature silicon oil within 0.1MPa. The experimental results show a similar pressure drop with the theoretical estimation according to a change of the flow velocity and the magnetic field.

• Laser Solutions
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• v.1 no.1
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• pp.11-17
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• 1998

The electron beam welding system has the advantages of the high power density, narrow welding section, and small thermal distortion of a workpiece. Recently, the electron beam welding system is widely used to the airplane engineering, nuclear power plant, and automobile industry. In the present paper, the structural analyses on the vacuum chamber of the electron beam welding system are performed by the F.E.M. analysis. The stiffening characteristics on the geometric shape, stiffener height and stiffener span are investigated. The deflection of the stiffened vacuum chamber under pressure is minimized by longitudinal and transverse stiffeners which are continuous in both direction.

• Advances in nano research
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• v.9 no.2
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• pp.91-104
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• 2020

The bending, stability (buckling) and vibration response of nano sized beams is presented in this study based on the Eringen's nonlocal elasticity theory in conjunction with the Euler-Bernoulli beam theory. For this purpose, the bending, buckling and vibration problem of Euler-Bernoulli nanobeams are developed and solved on the basis of nonlocal elasticity theory. The effects of various parameters such as nonlocal parameter e₀a, length of beam L, mode number n, distributed load q and cross-section on the bending, buckling and vibration behaviors of carbon nanotubes idealized as Euler-Bernoulli nanobeam is investigated. The transverse deflections, maximum transverse deflections, vibrational frequency and buckling load values of carbon nanotubes are given in tables and graphs.

• Archives of Craniofacial Surgery
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• v.18 no.1
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• pp.5-8
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• 2017

Among the classification of maxillary fracture, the Le Fort classification is the best-known categorization. Le Fort (1901) completed experiments that determined the maxilla areas of structural weakness which he designated as the "lines of weakness". According to these results, there are three basic fracture line patterns (transverse, pyramidal and craniofacial disjunction). A transverse fracture is a Le Fort I fracture that is above the level of the apices of the maxillary teeth section, including the entire alveolar process of the maxilla, vault of the palate and inferior ends of the pterygoid processes in a single block from the upper craniofacial skeleton. Le Fort fractures result in both a cosmetic and a functional deficit if treated inappropriately. In this article, authors review the management of a Le Fort I fracture with a case-based discussion.

• Structural Engineering and Mechanics
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• v.60 no.1
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• pp.163-173
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• 2016

Nowadays using Carbon Fiber Reinforced Polymer (CFRP) has been expanded in strengthening steel structures. Given that few studies have taken about strengthening of steel hollow pipe sections using CFRP, in present study, the effects of CFRP sheets using two layers as well as in combination with additional reinforcing strips has been assessment. Strengthening of five specimens was carried out in laboratory tests. As well as numerical simulation was performed for all specimens by Finite Element Method (FEM) using ABAQUS software and high correlation between the results of numerical models with experimental data indicate the power of FEM in this field. The results of both laboratory and simulated specimens showed that load-bearing capacity of circular cross-sections can be significantly increased using CFRP retrofitting technique. Also, application of additional CFRP reinforcing strips and layers caused more strength for the strengthened specimens.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.1
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• pp.21-29
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• 2017

Purpose of this study is to investigate structural behavior of the rectangular hollow column with various transverse reinforcement details. Experimental variables are diameter, arrangement details and lateral spacing of cross tie. A total of 66 column specimens have been prepared and tested under axial compressive load. Test results showed that behaviors of column specimens were different depending on the cross tie details. Specimens with cross tie wrapping longitudinal steel and transverse steel have greater strength and ductility than specimens with cross tie wrapping the longitudinal steel.

• ALGAE
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• v.20 no.3
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• pp.233-238
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• 2005

The photosynthetic parameters of dark- adapted minimum fluorescence (Fo) and maximum quantum yield of charge separation in PSII (Fv/Fm) were measured in transverse sections of eight species of marine Phaeophyceae (species of Laminariales, Fucales, Desmarestiales, Chordariales) using pulse amplified modulation (PAM) fluorometry. Within each transverse section fluorescence was measured in three regions corresponding to outer cortical and meristoderm cells, inner cortical cells and innermost medullary cells. Minimum fluorescence declined from 19-74% (mean of 39%) from outermost to innermost cells. Maximum quantum yield varied from 0.51-0.59 in outermost cell layers and this was reduced to 0.23-0.40 in innermost cell layers, with an average reduction of 50%. Despite the reduction Fo in medullary cells (inner), medullas of all species showed maximum quantum yields consistent with a photosynthetic role in carbon fixation. These results show that medullary cells of complex brown algae have more than a role in structure, storage or transport, and may also provide an important role in carbon fixation.