• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.97-102
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• 2004

The Characteristics of noise and vibration by heavy-weight floor impact sound was studied. Resonance frequency increased a little in structures that use damping material in living room and bedroom, and acceleration waves length that respond became short, and displayed aspect that oscillation level decreases. Result that measure sound pressure level, structure that compare and applies damping materials with structure that apply the resilient materials from 63Hz lower part that impact energy is concentrated in energy spectrum of heavy-weight floor impact sound displayed result that sound pressure, level decreases remarkably. Therefore, according to use of damping materials, confirmed reduction effect of heavy-weight floor impact sound.

• The Journal of the Korean dental association
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• v.55 no.1
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• pp.72-81
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• 2017

Regardless of the type of impression being made, the tray is the most important part of the impression-making procedure for completely edentulous patients. Dentists have to make use of a combination of rigid, thermoplastic, and resilient materials and control step-by-step procedure from irreversible hydrocolloid impression to definitive cast fabrication. For successful edentulous impression, some considerable clinical tips were guided.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.5 s.143
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• pp.499-505
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• 2005

Underwater explosion shock response analysis of a nonlinear double resiliently mounted equipment on a MIL-S-901D Large floating Shock Platform(LFSP) was carried out using LS-DYNA3D/USA. As a nonlinear double resiliently mounted equipment, real main engine module of naval ship was considered, where the engine, bearing, and base frame including sound enclosure were treated as rigid bodies with six degrees of freedom. The nonlinear effects of resilient mounts on its shock response characteristics were examined, and the usefulness of our suggested method was also confirmed comparing with calculation results by the equipment maker.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.805-814
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• 2008

This study focused on the resilient modulus prediction model, which is the functions of mean effective principal stress and axial strain, for three types of railroad trackbed materials such as crushed stone, weathered soil, and crushed-rock soil mixture. The model is composed with the maximum Young's modulus and nonlinear values for higher strain in parallel with dynamic shear modulus. The maximum values is modeled by model parameters, $A_E$ and the power of mean effective principal stress, $n_E$. The nonlinear portion is represented by modified hyperbolic model, with the model parameters of reference strain, ${\varepsilon}_r$ and curvature coefficient, a. To assess the performance of the prediction models proposed herein, the elastic response of a test trackbed near PyeongTaek, Korea was evaluated using a 3-D nonlinear elastic computer program (GEOTRACK) and compared with measured elastic vertical displacement during the passages of freight and passenger trains. The material types of sub-ballasts are crushed stone and weathered granite soil, respectively. The calculated vertical displacements within the sub-ballasts are within the order of 0.6mm, and agree well with measured values with the reasonable margin. The prediction models are thus concluded to work properly in the preliminary investigation.

• The Journal of the Acoustical Society of Korea
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• v.26 no.2E
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• pp.50-55
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• 2007

SBN (Structure-Borne Noise) reduction in resiliently mounted machineries are predicted by using mass-spring model and wave model. In mass-spring model, mount is modeled as a spring, while in wave model, mount is considered as an equivalent elastic rod for taking account into longitudinal wave propagation. The predictions for SBN reduction through mounts are compared to the measurements for four different pumps. It is found that the mass-spring model is valid only in low frequency range below few hundred Hz, while for high frequency ranges longitudinal wave propagation in the mount must be considered to explain the measurements. It is also shown that impedance of the floor slightly affects low frequency behaviour in mass-spring and wave model below 50 Hz - 80 Hz, so that in engineering practice the effect of floor impedance may be neglected in computing mount performance.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.165-175
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• 2009

With the current move towards adopting mechanistic-empirical concepts in the design of pavement structures, state-of-the-art mechanistic analysis methodologies are needed to determine accurate pavement responses, such as stress, strain, and deformation. Previous laboratory studies of pavement foundation geomaterials, i.e., unbound granular materials used in base/subbase layers and fine-grained soils of a prepared subgrade, have shown that the resilient responses followed by nonlinear, stress-dependent behavior under repeated wheel loading. This nonlinear behavior is commonly characterized by stress-dependent resilient modulus material models that need to be incorporated into finite element (FE) based mechanistic pavement analysis methods to predict more realistically predict pavement responses for a mechanistic pavement analysis. Developed user material subroutine using aforementioned resilient model with nonlinear solution technique and convergence scheme with proven performance were successfully employed in general-purpose FE program, ABAQUS. This numerical analysis was investigated in predicted critical responses and domain selection with specific mesh generation was implemented to evaluate better prediction of pavement responses. Results obtained from both axisymmetric and three-dimensional (3D) nonlinear FE analyses were compared and remarkable findings were described for nonlinear FE analysis. The UMAT subroutine performance was also validated with the instrumented full scale pavement test section study results from the Federal Aviation Administration's National Airport Pavement Test Facility (FAA's NAPTF).

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.623-630
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• 2012

Formation used as trackbed foundation for providing vertical bearing capacity onto rail foundation are composed of crushed stones usually with certain type of grain size distribution. Permanent deformation in trackbed foundation can be generated by increasing number of load repetition due to train traffic increases, causing track irregularity. In this study, a specially prepared trackbed foundation materials (M-40) used in Korea has been tested using a large repetitive triaxial compression apparatus in order to understand resilient and permanent deformation characteristics of the material. From these test results, resilient and permanent deformation characteristic are analyzed so that a permanent deformation model is developed which can consider number of load repetition N, confining stress (${\sigma}_3$), shear stress ratio(${\tau}/{\tau}_f$) and stiffness of the material.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.109-116
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• 2021

In order to replace mineral aggregate used as road pavement materials with steel slag aggregate, this present study evaluated mechanical properties of SMA Concrete mixtures using steel slag aggregate as oxidized slag from electric furnace in iron works. The variables of this experiment are the aggregate type of mineral and steel slag and the sieve sized of 10mm and 13mm. The physical properties inclu ding the specific gravity and absorption rate etc. of the slag aggregate mixtu res satisfied the KS standard as asphalt mixtu re. As a resu lt of evalu ating the mechanical properties of the asphalt mixtures, the optimum asphalt content of the slag aggregate mixtures were lower than that of the mineral aggregate mixtures, but other quality standards were all satisfied. In the deformation strength evaluation, the slag aggregate mixtures were measu red slightly higher than that of the mineral aggregate mixtu res, and the dynamic stability test satisfied the 2,000pass/mm standard value in all specimens. And, the moduli of resilient of the slag aggregate mixtures showed an improved value compared with the mineral aggregate mixtures. Therefore, as the resilient rate of the slag aggregate mixtures improved, it is speculated that there will be an effect of improving public performance according to the repeated traffic load of the vehicle.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.256-256
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• 2006

The design and synthesis of novel biomolecular materials, based on mimicking the properties of molecules found in nature, is providing materials with unusual properties. Resilin serves as an energy storage material in insects and facilitates flight, jumping (in fleas, froghoppers etc) and sound production (cicadas, etc). Resilin is initially produced as a soluble protein and in its mature form is crosslinked through formation of dityrosine units into a very large insoluble polymer. In the present study, we have synthesized a recombinant form of resilin that can be photochemically cross-linked into a resilient, rubber-like biomaterial that may be suitable for spinal disc implants. This material is almost perfectly elastic and its fatigue lifetime in insects must be >500 million cycles.

• International Journal of Railway
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• v.6 no.3
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• pp.112-119
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• 2013

A mid-size RC test apparatus (MRCA) equipped with a program is developed that can test samples up to D=10 cm diameter and H=20 cm height which are larger than usual samples used in practice. Using the developed RC test apparatus, two types of crushed trackbed foundation materials were tested in order to get the shear modulus reduction curves of the materials with changing of shear strain levels. For comparison purpose, large repetitive triaxial compression tests (LRT) with samples of height H=60cm and diameter D=30 cm were performed also. Resilient modulus obtained from the LRT was converted to shear modulus by considering elastic theory and strain level conversion and were compared to shear modulus values from the MRCA. It is found from this study that the MRCA can be used to test the trackbed foundation materials properly. It is found also that strain levels of $E_{v2}$ mostly used in the field should be verified considering the shear modulus reduction curves and proper values of $E_{v2}$ of trackbed foundation must be used considering the strain level verified.