• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.6
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• pp.341-348
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• 2019

The purpose of this study is to model and analyze retractable large spatial structures by applying parametric modeling techniques. The modeling of wind loads in the analysis of typical structures including curved surfaces can be error-prone, and the processing time increases dramatically when there are many types of variables. However, the method based on StrAuto that was developed in previous research, facilitates the efficacious assignment of wind loads to structures and the rapid arrival of conclusions. As a result, it is possible to compare alternatives with various loads, including wind loads, to determine an optimal alternative much faster than the existing process. Further, it is almost impossible to directly input the wind load by calculating the area of an irregularly curved surface. However, the proposed method automatically assigns the wind load, which allows for automatic optimization in a structural analysis system. The approach was applied and optimized using several models, and the results are presented.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.780-788
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• 2009

AE technique was applied to the static structural test of the composite wing structure to evaluate the structural integrity and damage. During the test, strain and displacements measurement technique were used to figure out for static structural strength. AE parameter analysis and source location technique were used to evaluate the internal damage and find out damage source location. Design limit load test, the 1st and 2nd design ultimate load tests and fracture test were performed. Main AE source was detected by an sensor attached on skin near by front lug. Especially, at the 1st design ultimate test, strain and displacements results didn't show internal damage but AE signal presented a phenomenon that the internal damage was formed. At the fracture test, AE activities were very lively, and strain and displacements results showed a tendency that the load path was changed by severe damage. The internal damage initiation load and location were accurately evaluated during the static structural test using AE technique. It is certified from this paper that AE technique is useful technique for evaluation of internal damage at static structural strength test.

• Journal of the Society of Disaster Information
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• v.9 no.1
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• pp.1-10
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• 2013

The main objective of this research is to develop the Mechanistic-Empirical (M-E) guidelines for evaluating the capacity of existing highways to sustain route overweight truck traffic over a specified performance period due to a growing concern on the impact of increasing overweight truck loads on highways. In this study, a two-stage framework was developed for this purpose. Level I procedure involves the use of pavement evaluation charts to identify the best possible route from among the alternatives considered and to determine what additional tests and analyses are needed as a screening tool. Level II involves the application of the Overweight Truck Route Analysis (OTRA) program to evaluate the structural adequacy of an existing route to carry routine overweight truck traffic over the specified performance period along with estimating asphalt concrete overlay thickness, if necessary.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5C
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• pp.199-206
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• 2009

This paper presents full scale model tests on the various types of model piles carried out to estimate the behavior of laterally loaded steel-concrete composite piles. Subgrade-reaction spring system was developed to simulate the reaction of ground in laboratory condition. In addition, lateral behavior of piles under working load condition was estimated using composite loading system, which is available for independent loading in vertical and horizontal direction. Steel-concrete composite piles showed higher efficiency in lateral resistance rather than drilled shaft made of reinforced concrete. The lateral resistance of composite pile was larger than the summation of steel pile and concrete pile due to the composite effect by steel casing. The effect of shear key or strength of concrete on the behavior of composite pile was examined. The substitution of reinforcing bar by steel casing was also investigated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.2
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• pp.11-22
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• 1990

An automatic incremental algorithm for geometric non-linear finite element analysis of the structures subjected to the conservative and non-conservative forces is presented. By making efficient combination of the load incremental method and the displacement incremental method, this scheme can trace various post-buckling equilibrium path such as snap-through and turning-back. Several numerical examples to demonstrate the feasibility of the present algorithm, over ranges of deformation that are well beyond those likely to occur in practical structures, are given and discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.3
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• pp.21-30
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• 1989

In this study, the dynamic behavior of a continuous bridge under moving load is studied considering roughness of the road surface. Vehicle model includes the spring effects of axes, and due to these effects, equations of motions for the vehicle and bridge are derived in coupled form. And then iteration method is used to solve the equations. In experimental study a bridge model is constructed considering the similarity rule in order that the model exhibits dynamic behavior similar to that of prototype. Three types of roughness such as uneven random roughness, uplift on the approach and piece-wise constant roughness are used to describe road roughness. Through the numerical analysis and experiments, the effects of surface roughness, sprung mass, and velocity on the dynamic behavior of the bridge are examined.

• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.87-98
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• 2007

Generally, main girders and steel piers of temporary bridges form the steel rahmen structure. In this study, the rational stability design procedure for main members of temporary bridges was presented using a 3D system buckling analysis and second-order elastic analysis. Six types of temporary bridges, which can be designed and fabricated in reality, were chosen and the buckling design for them was performed in consideration ofload combinations of dead and live loads, thermal load, and wind load. Effective buckling length of steel piers, transition of 3D buckling modes, and effects of second-order analysis were investigated through a case study involving six temporary bridges.

• Composites Research
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• v.13 no.4
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• pp.1-10
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• 2000

SiC particulate reinforced metal matrix composites(MMCs) are emerging as candidate materials for the automobile and aerospace industries due to their significant increase in elastic modulus and strength compared to conventional metallic materials. However, in order to make successful application of MMCs, it is very important to understand micro-failure mechanism under cyclic loading because failure mechanism of MMC is dominated by accumulation of micro-failure due to applied loading. In this study, ultrasonic Lamb wave and acoustic emission(AE) have been used to monitor microscopic damage accumulation under cyclic loading for SiC particulate reinforced metal matrix composite(SiCp/A356). It was found that the change in velocity and attenuation of ultrasonic Lamb wave due to the increase of loading cycles could be characterized by three different stages corresponding to the microscopic fracture processes. The characteristic of AE signal at each stage was analyzed and discussed by comparing with the change of ultrasonic characteristic in MMCs.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.3
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• pp.391-399
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• 2001

Three-dimensional dynamic analysis of underground openings subjected to explosive loadings considering the effects of water saturation is carried out in this study. The surrounding rock mass is assumed to be the limestone with 13.5% of porosity. Two calculations are compared using as identical explosive charge; the first in dry rock of 13.5% porosity, the second in the identical rock, but in a fully saturated condition. It is shown that velocity, displacement, and stress time histories are higher in saturated rock than those in dry rock through numerical studies. It is also shown that underground openings in saturated rock masses could be significantly more vulnerable to the potential damages associated with shear failure than those in dry medium.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.161-168
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• 2010

Practicing engineers and researchers need computational tools that estimate accurately the cyclic response of RC walls, and in particular, force and deformation capacities and their materials strains. So this paper describes a nonlinear truss modeling approach for reinforced concrete walls, or in general, for plane stress reinforced concrete elements subjected to cyclic reversals. Nonlinear vertical, horizontal, and diagonal truss elements are used to represent concrete and steel reinforcement. The wall having aspect ratio of 1.2 was chosen to be compared with the experimental results. Here, four types of main diagonal member models and three types of diagonal members models were applied to find out more accurate results of analysis.