• Journal of the Korea institute for structural maintenance and inspection
• /
• v.12 no.2
• /
• pp.149-155
• /
• 2008

The road construction, as part of effort to ease the worsening traffic, has been underway throughout the nation, while the existing road has been increasingly losing its load carrying capacity due to such factors as heavy traffic and weathering. In the case of site, the soil type, plasticity index, and specific gravity were SC, 12.2%, and 2.66, respectively. The maximum dry density, optimum moisture content and modified CBR were $1.895g/cm^3$ (Modified Compaction D), 13.6%, and 16.2%, respectively. A correlation of coefficient expressed good interrelationship by 0.90 between the CBR estimated from a dynamic penetration index of dynamic cone penetrometer test and a deformation modulus converted from a dynamic deflection modulus obtained from a portable FWD test.

• Journal of Korea Society of Industrial Information Systems
• /
• v.25 no.2
• /
• pp.19-27
• /
• 2020

Recently, rapid and accurate 3D models creation is required in various applications using virtual reality and augmented reality technology. In this paper, we propose an on-site learning based shape deformation method which transforms the clothed 3D human model into the shape of an input point cloud. The proposed algorithm consists of two main parts: one is pre-learning and the other is on-site learning. Each learning consists of encoder, template transformation and decoder network. The proposed network is learned by unsupervised method, which uses the Chamfer distance between the input point cloud form and the template vertices as the loss function. By performing on-site learning on the input point clouds during the inference process, the high accuracy of the inference results can be obtained and presented through experiments.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.3
• /
• pp.89-100
• /
• 2007

In the companion paper, we provided the novel elastic-plastic constitutive model based on the micromechanics theory. Herein, the elastic and elastic-plastic deformation of granular soils is meticulously analyzed. To guarantee high accuracy of the microscopic parameter, the systematic procedure to evaluate the parameters is provided. The analysis of the elastic response during the isotropic and triaxial compression shows that the stress-level dependency of cross-anisotropic elastic moduli is induced by the power relationship of the contact force in the normal contact stiffness, while the evolution of fabric anisotropy is more pronounced during triaxial compression. The micromechanical analysis indicates that the plastic strains are likely to occur at very small strains. The plastic deformation of tangential contacts has an important role in the reduction of soil stiffness during axial loading.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.2
• /
• pp.64-73
• /
• 2014

This study proposes a load identification for the safety monitoring of the steel structure based on measured strain data. Instead of parameterizing the stiffness of structure in the existing system identification researches, the loads on a structure and a matrix (the unit strain matrix) defined by the relationship between strain and load on structure are parameterized in this study. The error function is defined by the difference between measured strain and strain estimated by parameters. In order to minimize this error function, the genetic algorithm which is one of the optimization algorithm is applied and the parameters are found. The loads on the structure can be identified through the founded parameters and measured strain data. When the loads are changed, the unmeasured strains are estimated based on founded parameters and measured strains on changed state of structure. To verify the load identification algorithm in this paper, the static experimental test for 3 dimensional steel frame structure was implemented and the loads were exactly identified through the measured strain data. In case of loading changes, the unmeasured strains which are monitoring targets on the structure were estimated in acceptable error range (0.17~3.13%). It is expected that the identification method in this study is applied to the safety monitoring of steel structures more practically.

• Geotechnical Engineering
• /
• v.12 no.3
• /
• pp.109-126
• /
• 1996

In this study, the chemical fluid considered is sodium chloride sloutions. The concentrations for the sodium chloride solutions are varied from 0 to 20%. A series of lab oratory triaxial tests are performed on the cylindrical specimens of sand bentonite mixture with different (5, 10, 15%) sodium chloride content solutions. Deformation(elastic modulus, E) and strength (cohesion, c', and angle of friction, f') parameters are obtained from the triaxial tests and they are expressed as functions of conf'ming pressure and sodium chloride solution concentrations. The stress-strain-strength behavior based on the above strength parameters is introduced to the finite element method with a residual flow procedure (RFP). By integrating a slope stability (limit equilibrium) procedure in the finite element method, factors of safety with time are computed.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.5
• /
• pp.1193-1201
• /
• 1993

A new deformation resistance model for hot steel strip rolling process was formulated to improve the accuracy of roll force estimation. To improve the existing deformation resistance model more precisely, a modification function was introduced in this study. For the modification function, several factors considering material and operational conditions have been investigated and the optimal modification function was determined under the principle of minimum variability. The newly formulated modification function was applied to the deformation resistance model for ultra-low carbon steel and showed improved accuracy with about 30% decrease in terms of standard deviation of predicted roll force values against measured ones.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.4
• /
• pp.5-13
• /
• 2004

Strength and compressibility characteristics of Light-Weighted Foam Soil (LWFS) are experimentally investigated in the paper. LWFS is composed of the dredged soils, cement and air foam to reduce unit-weight and to increase compressive strength. For these purposes, both unconfined compression tests and triaxial compression tests are carried out fer artficially prepared specimens of LWFS with various initial water contents, cement contents, mixing ratio of silty dredged soils and different confining stresses. The experimental results of LWFS indicate that the stress-strain relationship and the compressive strength are strongly influenced by cement contents rather than intial water contents of the edged soils. In this paper, the normalizing scheme considering the ratio of initial water contents, cement contents, and air foam contents has been proposed to evaluate the relationship between compressive strength of LWFS and a normalized factor.

• Computational Structural Engineering
• /
• v.8 no.3
• /
• pp.79-89
• /
• 1995

Two-element plate concept is incorporated into the buckling problem in order to simplify the nonlinear distribution of stress through the thickness of plate. Finite element formulations and programs based upon the Reissner functional and the modified Reissner functional using two-element plate concept are developed for buckling analysis of plates under axial compression. The two programs have been applied to obtain the linear elastic buckling behavior of axially compressed flat plates. Excellent agreement of linear elastic-solution results with exact or approximate solutions of other authors for the same boundary conditions proves the validity of the finite element method using two-element plate theory.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.5
• /
• pp.1069-1078
• /
• 1990

It is shown that the performance of finite element based on energy orthogonal functions may be superior to conventional formulation for plane stress problem. Using this finite element, it is then attempted to show the distribution of stress concentration effect for subsurface under loading point. It turned out that the stress concentration effect for subsurface is not dependent on the width of the member but the loading area. And then it is shown that the solution attained by taking the stress function as a Fourier series is not satisfactory in y<0.1B.

• Computational Structural Engineering
• /
• v.7 no.4
• /
• pp.85-101
• /
• 1994

A family of variational principles governing the dynamics of laminated plate has been derived using a variationally consistent shear deformable discrete laminated plate theory with particular reference to finite element procedures. The theoretical basis for the derivation is Sandhu's generalized procedure for the variational formulation of linear coupled boundary value problem. As the bilinear mapping to write the operator matrix of the field equations in self-adjoint form, convolution product was employed. Boundary conditions, initial conditions and probable internal discontinuity were explicitly included in the governing functionals. Some interesting extensions and specializations of the general variational principle were presented, which can provide many different finite element formulations for the problem.