• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.6
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• pp.593-606
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• 2010

This paper presents a formulation to include the prestressing effects in available numerical models for the nonlinear material, instantaneous and long-term analysis of prestressed concrete shell structures, based on the displacement formulation of the finite element method. A four-node flat shell element is adopted for nonlinear analysis of prestressed concrete shells. This element was incorporated into an existing general-purpose finite element analysis program. A distinctive characteristic of the element is its capability to simulate the behavior of shells subjected to a variety of types of loading and drilling rotational stiffness. Consequently, the response of prestressed concrete shell structures can be predicted accurately using the proposed nonlinear finite element procedure.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.2
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• pp.29-42
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• 1990

Three dimensional frame structures with such nonlinearities as large displacements, medium rotations, plastic hinges and local defects are efficiently analyzed by introducing the nonlinear rotational spring. Formulations are based on the incremental updated Lagrangian descriptions and the virtual work principle, Axial displacement and twisted angle in beam elements are interpolated linearly, while bending displacements are approximated by the Hermite polynomials. The modified are length method is used as a solution method. The moment-angle of rotation relationship obtained analytically or experimentally can be easily incorporated into the solution procedure. Several examples tested show that the present method can be used efficiently in analyzing nonlinear frame structures with plastic hinges or local defect.

• Advances in Computational Design
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• v.4 no.4
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• pp.397-413
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• 2019

In this paper, static nonlinear analysis of gable frame is performed using OpenSees software. Both geometric and material nonlinearities are considered in analyses. To consider large displacements, co-rotational coordinate transformation is used in software. The effects of symmetric and asymmetric support conditions including clamped and simple supports are studied. On the other hand, the material nonlinearity is reflected on analyses using Giuffre-Menegotto-Pinto steel material. Note that strain hardening characteristics are also considered in this model. Moreover, I-shaped cross-section is assumed for all members. The results are provided for different geometry properties of gable frame including shallow and deep inclined roof. It should be added that buckling and post-buckling behaviors of gable frame are investigated using related equilibrium paths. A comparison study is also implemented on the responses of buckling loads obtained for different support and geometry conditions. To trace snap-through paths completely, a displacement control method entitled arc-length is utilized. Findings show the capability of proposed model in nonlinear analysis of gable frames.

• Journal of Korean Association for Spatial Structures
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• v.19 no.3
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• pp.101-109
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• 2019

In order to develop the compatible damping device in various vibration source, a hybrid wall-type damper combining slit and friction damper in parallel was developed. Cyclic loading tests and two-story RC reinforced frame tests were performed for structural performance verification. As a result of the 5-cyclic loading test according to KBC-2016 and low displacement cyclic fatigue test, The hybrid wall type damper increased its strength and the ductility was the same as that of the slit damper. In addition, As a result of the two-layer frame test, the reinforced frame had about twice the strength of the unreinforced frame, and the story drift ratio was satisfied to Life Safety Level.

• Steel and Composite Structures
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• v.38 no.3
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• pp.257-270
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• 2021

This paper presents a displacement-based numerical methodology following the Euler-Bernoulli theory to simulate the 2 nonlinear behavior of steel structures. It is worth emphasizing the adoption of co-rotational finite element formulations considering large displacements and rotations and an inelastic material behavior. The numerical procedures proposed considers plasticity concentrated at the finite elements nodes, and the simulation of the steel nonlinear behavior is approached via the Strain Compatibility Method (SCM), where the material constitutive relation is used explicitly. The SCM is also applied in determining the sections bearing capacity. Moreover, the present numerical approach is not limited to a specific structural member cross-sectional typology, with the residual stress models introduced explicitly in subareas of steel cross-sections generated by a 2D discretization. Finally, results consistent with the literature and with low processing time are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.995-999
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• 1995

In spindle-bearing system, the displacement characteristics of the bearing by the load applied on the spindle are affected greatly by the assembling tolerance between the spindle and housing assembled to support the bearing. Also in spindle system of rotational operation, the compliance characteristic of the bearing is expected to be varied frequently by the thermal deformation of the spindle and the housing. To predict the thermal deformation of the spindle including heat generation of the bearing, we need to examine the effect on the compliance of spindle-bearing system by the assembling tolerance. In this paper, we proposed the load-displacement relation expression considering the effect which the variation of contact pressure due to the radial directional assembling tolerance between the bearing and the housing influences on the axial and radial directional displacement characteristics of the bearing. Furthermore, for several assembling systems of bearings and housings having all different assembling tolerances, we proposed a method to predict exactly the variation of the bearing preload which is sensitive to the thermal deformation by showing the propriety with experimental results.

• Journal of Power System Engineering
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• v.14 no.3
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• pp.33-38
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• 2010

Technology of vehicle industry has been developing and it is required a better vehicle performance than before. Therefore, the consumers are asking not only an economic efficiency, functionality, polished design, ride comfort and silence but also a driving stability. The ride comfort, silence and driving stability are influenced by the size of vehicle and various facilities. But the principal factor is a room noise and vibration sensed by a driver and passenger. Thus, the NVH of vehicle has been raised and used as a principal factor for evaluation of vehicle performance. The primary objective of this study is an optimized design of powertrain mounting system. To optimized design was applied MSC.Nastran optimization modules. Results of dynamic analysis for powertrain mounting system was investigated. By theses results, design variables was applied 12 dynamic spring constant. And the weighting factor according to translational displacement and rotational displacement applied 3 cases. The objective function was applied to minimize displacement of powertrain. And the design variable constraint was imposed dynamic spring constant ratio. The constraint of design variable for objective function was imposed bounce displacement for powertrain.

• Geomechanics and Engineering
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• v.13 no.5
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• pp.809-823
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• 2017

This paper describes lab test results of artificial rock-like material samples having a plane joint. Cyclic shear tests were performed under different normal loads and different shear displacement amplitudes. For this purpose, multi-stage normal loading tests (30 kN, 60 kN, 90 kN, 180 kN, 360 kN and 480 kN) with cyclic excitation at frequency of 1.0 Hz and different shear displacement amplitudes (0.5 mm, 1.0 mm, 2.0 mm, 4.0 mm, 5.0 mm, and 8.0 mm) were conducted using the big shear box device GS-1000. Experimental results show, that shear forces increase with the increase of normal forces and quasi-static friction coefficient is larger than dynamic one. With the increase of normal loads, approaching the peak value of shear forces needs larger shear displacements. During each cycle the normal displacements increase and decrease (rotational behavior in every cycle). Peak angle of inclination increases with the increase of normal load. A phase shift between maximum shear displacement and maximum shear force is observed. The corresponding time shift decreases with increasing normal load and increases with increasing shear displacement amplitudes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.639-646
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• 2016

In this study, the contactless measurement method with a optical displacement sensor(ODS, ADNS 9500) was proposed to overcome flaws in a rotary encoder based measurement under particular circumstances, such as a slippage and a case of little rotational inertia. The performance tests of the optical displacement sensor using data acquisition board and National Instruments's LabVIEW program were performed to accomplish accurate displacement measurements and the performance characteristics according to measurement direction, speed, acceleration, height and surface types were discovered through the repetitive tests. The experimental results indicate that, in order to get an accurate in-plane motion, the height(distance between the ODS and the target surface) has to be maintained at the range of 2.4 mm to 3.2 mm and the sensitivity(resolution) should be modified and applied to the formulae for displacement calculation, considering its measurement direction, speed and surface type.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.158.1-158.1
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• 2003

We report here the results on N-acetyl-N"-methylamide of oxazolidine (Ac-Oxa-NHMe) calculated using the ab initio molecular orbital method with the self-consistent reaction field (SCRF) theory at the HF level of theory with the 6-31 +G(d) basis set. The displacement of the $\gamma$-$CH_2$ group in proline ring by oxygen atom has affected the structure of proline, cis-trans equilibrium, and rotational barrier. The up-puckered structure is found to be prevalent for the trans conformers of the Oxa amide. (omitted)