• Title/Summary/Keyword: Structural modification

Search Result 783, Processing Time 0.029 seconds

Noise Reduction of a Bank Teller Cash Recycler (은행 계원용 자동현금관리기의 소음 저감)

  • Won, Hong-In;Sim, Woojeong;Kim, Jaewon;Park, Changho;Kim, Jongwoo;Jung, Woochul;Chung, Jintai
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.26 no.3
    • /
    • pp.308-314
    • /
    • 2016
  • This paper proposes design guidances for noise reduction of a bank teller cash recycler(TCR). The operating noise of a TCR is required to be reduced because it bothers bank tellers and customers. The operating noise from a TCR is measured and the most influential driving system is examined. To find the main sources of the noise, the frequency spectra are analyzed by comparing with excitation frequencies of the driving system. From the analysis results, we reveals that the main sources of the noise are gear mesh frequency of a certain gear train and its side band frequencies, which is attributed by vulnerable support condition. Consequently, to reduce the operating noise, the structural modification for the gear train support is suggested and its effectiveness for the noise reduction is confirmed experimentally.

Analysis of Practical Dynamic Force of Structure with Inverse Problem (역문제에 의한 구조물의 실동하중 해석)

  • 송준혁;노홍길;김홍건;유효선;강희용;양성모
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.13 no.2
    • /
    • pp.75-80
    • /
    • 2004
  • Vehicle structures are composed of many substructure connected to one another by various types of mechanical joints. In vehicle engineering it is important to study these connected structures under various dynamic forces for the evaluations of fatigue life and stress concentration exactly. It is difficult to obtain the accurate load history of specified positions because of the errors such as modeling, measurement and etc. In the beginning of design exact load data are actually necessary for the fatigue strength and life analysis to minimize the cost and time of designing. In this paper, the procedure of practical dynamic force determination is developed by the combination of the principal stresses of F. E. Analysis and experiment. Least square pseudo inverse matrix is adopted to obtain in inverse matrix of analyzed stresses matrix. The error minimization method utilizes the inaccurate measured error and the shifting error that the whole data is stiffed over real data. The least square criterion is adopted to avoid these non. Finally, to verify the proposed procedure, a bus is analyzed. This measurement and prediction technology can be extended to the structural modification of any geometric shape in complex structure.

Shape Optimization of the Lower Control Arm using the Characteristic Function and the Fatigue Analysis (특성함수와 피로해석을 이용한 로워컨트롤암의 형상최적설계)

  • Park Youngchul;Lee Donghwa
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.13 no.1
    • /
    • pp.119-125
    • /
    • 2005
  • The current automotive is seeking the improvement of performance, the prevention of environmental pollution and the saving of energy resources according to miniaturization and lightweight of the components. And the variance analysis on the basis of structure analysis and DOE is applied to the lower control am. We have proposed a statistical design model to evaluate the effect of structural modification by performing the practical multi-objective optimization considering weight, stress and fatigue lift. The lower control arm is performed the fatigue analysis using the load history of real road test. The design model is determined using the optimization of acquired load history with the fatigue characteristic. The characteristic function is made use of the optimization according to fatigue characteristics to consider constrained function in the optimization of DOE. The structure optimization of a lower control arm according to fatigue characteristics is performed. And the optimized design variable is D=47 m, T=36mm, W=12 mm. In the real engineering problem of considering many objective functions, the multi-objective optimization process using the mathematical programming and the characteristic function is derived an useful design solution.

Recent Advances in Tyrosinase Research as An Industrial Enzyme (산업용 효소로써 티로시나아제 연구의 최근 동향)

  • Kim, Hyerin;Kim, Hyunmi;Choi, Yoo Seong
    • KSBB Journal
    • /
    • v.29 no.1
    • /
    • pp.1-8
    • /
    • 2014
  • Tyrosinases catalyze the hydroxylation of monophenolic compounds and the conversion of o-diphenols to oquinones. The enzymes are mainly involved in the modification of tyrosine into L-3,4-dihydroxyphenyl-alanine (L-DOPA) and DOPA/DOPAquinone-drived intermolecular cross-linking, which play the key roles of pigmentation to the cells. It is ubiquitously distributed in microorganisms, plants, and animals all around the nature world. They are classified as copper- containing dioxygen activating enzymes; two copper ions are coordinated with six histidine residues in their active sites and they are distinguished as met-, deoxy-, and oxy-form depending on their oxidative states. Natural extraction and recombinant protein approaches have been tried to obtain practical amounts of the enzymes for industrial application. Tyrosinases have been widely applied to industrial and biomedical usages such as detoxification of waste water containing phenolic compounds, L-DOPA as a drug of Parkinson's disease, biomaterials preparation based on the cross-linking ability and biosensors for the detection of phenolic compounds. Therefore, this review reports the mechanism of tyrosinase, biochemical and structural features and potential applications in industrial field.

Modeling and prediction of buckling behavior of compression members with variability in material and/or section properties

  • Gadalla, M.A.;Abdalla, J.A.
    • Structural Engineering and Mechanics
    • /
    • v.22 no.5
    • /
    • pp.631-645
    • /
    • 2006
  • Buckling capacity of compression members may change due to inadvertent changes in the member section dimensions or material properties. This may be the result of repair, modification of section properties or degradation of the material properties. In some occasions, enhancement of buckling capacity of compression members may be achieved through splicing of plates or utilization of composite materials. It is very important for a designer to predict the buckling resistance of the compression member and the important parameters that affect its buckling strength once changes in section and/or material properties took place. This paper presents an analytical approach for determining the buckling capacity of a compression member whose geometric and/or material properties has been altered resulting in a multi-step non-uniform section. This analytical solution accommodates the changes and modifications to the material and/or section properties of the compression member due to the factors mentioned. The analytical solution provides adequate information and a methodology that is useful during the design stage as well as the repair stage of compression members. Three case studies are presented to show that the proposed analytical solution is an efficient method for predicting the buckling strength of compression members that their section and/or material properties have been altered due to splicing, coping, notching, ducting and corrosion.

Analytical solutions for static bending of edge cracked micro beams

  • Akbas, Seref Doguscan
    • Structural Engineering and Mechanics
    • /
    • v.59 no.3
    • /
    • pp.579-599
    • /
    • 2016
  • In this study, static bending of edge cracked micro beams is studied analytically under uniformly distributed transverse loading based on modified couple stress theory. The cracked beam is modelled using a proper modification of the classical cracked-beam theory consisting of two sub-beams connected through a massless elastic rotational spring. The deflection curve expressions of the edge cracked microbeam segments separated by the rotational spring are determined by the Integration method. The elastic curve functions of the edge cracked micro beams are obtained in explicit form for cantilever and simply supported beams. In order to establish the accuracy of the present formulation and results, the deflections are obtained, and compared with the published results available in the literature. Good agreement is observed. In the numerical study, the elastic deflections of the edge cracked micro beams are calculated and discussed for different crack positions, different lengths of the beam, different length scale parameter, different crack depths, and some typical boundary conditions. Also, the difference between the classical beam theory and modified couple stress theory is investigated for static bending of edge cracked microbeams. It is believed that the tabulated results will be a reference with which other researchers can compare their results.

Biomimetics of the extracellular matrix: an integrated three-dimensional fiber-hydrogel composite for cartilage tissue engineering

  • Coburn, Jeannine;Gibson, Matt;Bandalini, Pierre Alain;Laird, Christopher;Mao, Hai-Quan;Moroni, Lorenzo;Seliktar, Dror;Elisseeff, Jennifer
    • Smart Structures and Systems
    • /
    • v.7 no.3
    • /
    • pp.213-222
    • /
    • 2011
  • The native extracellular matrix (ECM) consists of an integrated fibrous protein network and proteoglycan-based ground (hydrogel) substance. We designed a novel electrospinning technique to engineer a three dimensional fiber-hydrogel composite that mimics the native ECM structure, is injectable, and has practical macroscale dimensions for clinically relevant tissue defects. In a model system of articular cartilage tissue engineering, the fiber-hydrogel composites enhanced the biological response of adult stem cells, with dynamic mechanical stimulation resulting in near native levels of extracellular matrix. This technology platform was expanded through structural and biochemical modification of the fibers including hydrophilic fibers containing chondroitin sulfate, a significant component of endogenous tissues, and hydrophobic fibers containing ECM microparticles.

comparative Study of Analytical Modal Properties of Instrumentation Cabinet of Nuclear Power Plant (모델링 방법의 차이에 따른 원전계측캐비넷의 동특성 해석 결과 비교분석)

  • 조양희
    • Proceedings of the Earthquake Engineering Society of Korea Conference
    • /
    • 1999.10a
    • /
    • pp.186-192
    • /
    • 1999
  • Safety-related equipments of nuclear power plant must be seismically qualified to demonstrate their ability to function as required during and/or after the earthquake, The seismic qualification is usually achieved through analysis and testing. Analysis method is preferably adopted for structurally simple equipments which are easy to be mathematically modeled. However even for relatively complex equipments analysis method is occasionally used for computing the input motion or supporting information for the component test followed. Electrical cabinet is a typical example for which analysis method is combinedly used with test to get modal properties of the enclosing cabinet structure. Usually the structural elements and doors of the cabinet are loosely interconnected with small-size bolts or spot welding. Therefore cabinet-type equipment usually has high and complex nonlinear properties which are not easily idealized by simple practical modeling techniques. in this paper with respect to a typical cabinet-type structure(instrumentation cabinet of nuclear power plant) a comparative study has been performed between three different state-of-the -art modeling techniques: lumped mass model frame model and FEM modal. Form the study results it has been found that modal properties of the cabinet-type structure in the elastic behavior range can be reasonably computed through any type of modeling techniques in the practice with slight modification of model properties to get better accuracy. However it needs additional modeling techniques to get reasonable results up to nonlinear range.

  • PDF

A study on the CAD for extension of sweet spot of the tennis racket (테니스 라켓의 안정타점영역의 확장을 위한 CAD화에 관한 연구)

  • Oh, Jae-Eung;Park, Ho;Hong, Ha-Yoon;Yum, Sung-Ha
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.12 no.1
    • /
    • pp.95-105
    • /
    • 1988
  • The dynamic characteristics of a tennis racket were identified by experimental modal analysis and the sweet spot due to these was calculated. A tennis racket was selected as a model reference and modal parameters of the racket were estimated from the transfer function measured by experiment. The transfer function was reconstructed by the modified modal parameters on the assumption that the racket was locally modified, for example, a change in the material of the frame and the attachment of a damping material to the grip. The change of the dynamic characteristics, especially natural frequency and magnitude of the second and the third vibrational modes, were evaluated from the reconstructed transfer function. The change of the sweet spot due to the modified modal parameters was estimated and visualized through computer graphic simulation by the criterion of the sweet spot measured before structural modification. The modal parameters for improvement of the dynamic characteristics.

Stress analysis of non carious cervical lesion and cervical composite resin restoration (지상강좌 1 - 비우식성 치경부병소와 치경부 복합레진수복의 응력분석)

  • Park, Jeong-Kil
    • The Journal of the Korean dental association
    • /
    • v.48 no.4
    • /
    • pp.297-307
    • /
    • 2010
  • Noncarious cervical lesions(NCCLs) are characterized as structural defects found on the tooth surface of the cement-enamel junction. Loss of tooth structure through noncarious mechanisms may vary in etiology and clinical presentation for each individual but presently many clinician now classify this as tooth failure of abfraction due to the stress applied in the cervical area of the tooth under oral physiological and pathological loads. In the current study, we investigated the stress distribution of maxillary premolar with NCCL using simulated 3D finite element analysis. The results were as follows: 1. In the sound maxillary premolar, the stresses were highly concentrated at cervical enamel surface of the mesiobuccal line angle, asymmetrically. 2. Once the lesion has been formed, the highest stress concentration was observed around the apex of the wedge shaped lesion. 3. In four types of NCCL, the patterns of stress distribution were similar and the peak stress was observed at mesial corner and also stresses concentrated at lesion apex. 4. Lesion cavity modification of rounding apex, reduced stress of lesion apex. 5. When restoring the notch-shaped lesion, material with high elastic modulus worked well at the lesion apex and material with low elastic modulus worked well at the cervical cavosurface margin.