• Title/Summary/Keyword: displacement-controlled method

Search Result 114, Processing Time 0.025 seconds

FEM Analysis of Controlled Low Strength Materials for Underground Facility with Bottom Ash (바톰애쉬를 이용한 지하매설관용 유동성뒤채움재의 FEM 해석)

  • Lee, Kwan-Ho;Lee, Kyung-Jung
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.13 no.5
    • /
    • pp.2368-2373
    • /
    • 2012
  • In this research, finite element method was carried out to evaluate the defomation of pipe and surface displacement for backfill of underground ficility. Various conditions for analysis were employer, including two different pipes(PE and concrete pipe), two different excavation depth(60cm and 150cm) and width(1.5D and 2D), a regular sand backfill, and four different flowable backfills. The vertical deformation of 60 cm diameter for PE was measured three times more than that of 30 cm diameter. The measured deformations for regular backfill and four flowable backfills were 0.320mm, and 0.135mm to 0.155mm, respectively. It ratio was around 40%. In case of 30cm diameter of concrete pipe, the measured vertical defomation was around 0.004mm for all the backfill materials. In case of installation depth, the effect of flowable backfill for flexible pipe is better than for rigid pipe. There is little effect on the deformation of concrete pipe with regular sand backfill and flowable backfill.

Stress Analysis of the Cylinder Block and the Valve Plate of the Swash Plate Type Oil Hydraulic Piston Pump (사판식 유압 픽스톤 펌프의 실린더블록과 밸브 플레이트의 응력해석)

  • Kim J. H.;Cho I. S.;Baek I. H.;Jung Jae-Youn;Oh Suk-Hyung
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • 2004.11a
    • /
    • pp.255-260
    • /
    • 2004
  • Recently, the technologies related to the swash plate type oil hydraulic piston pump are requiring extreme technologies to overcome the limit of high efficiency in cope with high speed and pressure, and are devoted to compact the unit, to gain low noise level, and to adopt electronic technologies, and the question regarding to maximize the mechanical efficiency, that is, to minimize the torque loss by minimizing the leakage loss in the relative sliding region but these are in trade-off relation that tribological responding is very difficult. Cylinder block-valve pate in high speed relative sliding motion has the characteristics that should be extremely controlled for the optimization of these leakage loss and mechanical efficiency, and pressure resistance designing of them is important for high pressure performance. But, studies on the stress analysis of these parts have not been performed briskly, so in this paper the stress distribution and the region where the highest displacement appears are described through the static stress analysis using CATIA V5. Through the future studies on these theme, it has the purpose of finding the suitable materials for the other parts as well as cylinder block and valve plate, in cope with high pressure operation through the stress analysis with the most similar conditions for the practical operation.

  • PDF

Robust Design and Thermal Fatigue Life Prediction of Anisotropic Conductive Film Flip Chip Package (이방성 전도 필름을 이용한 플립칩 패키지의 열피로 수명 예측 및 강건 설계)

  • Nam, Hyun-Wook
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.28 no.9
    • /
    • pp.1408-1414
    • /
    • 2004
  • The use of flip-chip technology has many advantages over other approaches for high-density electronic packaging. ACF (anisotropic conductive film) is one of the major flip-chip technologies, which has short chip-to-chip interconnection length, high productivity, and miniaturization of package. In this study, thermal fatigue lift of ACF bonding flip-chip package has been predicted. Elastic and thermal properties of ACF were measured by using DMA and TMA. Temperature dependent nonlinear hi-thermal analysis was conducted and the result was compared with Moire interferometer experiment. Calculated displacement field was well matched with experimental result. Thermal fatigue analysis was also conducted. The maximum shear strain occurs at the outmost located bump. Shear stress-strain curve was obtained to calculate fatigue life. Fatigue model for electronic adhesives was used to predict thermal fatigue life of ACF bonding flip-chip packaging. DOE (Design of Experiment) technique was used to find important design factors. The results show that PCB CTE (Coefficient of Thermal Expansion) and elastic modulus of ACF material are important material parameters. And as important design parameters, chip width, bump pitch and bump width were chose. 2$^{nd}$ DOE was conducted to obtain RSM equation far the choose 3 design parameter. The coefficient of determination ($R^2$) for the calculated RSM equation is 0.99934. Optimum design is conducted using the RSM equation. MMFD (Modified Method for feasible Direction) algorithm is used to optimum design. The optimum value for chip width, bump pitch and bump width were 7.87mm, 430$\mu$m, and 78$\mu$m, respectively. Approximately, 1400 cycles have been expected under optimum conditions. Reliability analysis was conducted to find out guideline for control range of design parameter. Sigma value was calculated with changing standard deviation of design variable. To acquire 6 sigma level thermal fatigue reliability, the Std. Deviation of design parameter should be controlled within 3% of average value.

Performance Evaluation of Vibration Control According to Installation Location of a Sky-bridge (스카이브릿지 설치위치에 따른 고층건물의 진동제어 성능평가)

  • Kim, Hyun-Su;Park, Yong-Koo;Ko, Hyun;Lee, Ui-Hyun;Lee, Dong-Guen
    • Journal of Korean Association for Spatial Structures
    • /
    • v.10 no.3
    • /
    • pp.65-74
    • /
    • 2010
  • In this study, the vibration control effect according to the installation location of the sky-bridge and the difference of natural periods of the connected buildings has been investigated. To this end, 40-story and 50-story building structures connected by a sky-bridge were used as example structures and the equivalent modeling method was used. Boundary nonlinear time history analyses were performed using El Centro and Taft earthquakes to investigate the dynamic behavior of the example structures and vibration control effect of the sky-bridge. Based on numerical results, it has been shown that displacement responses can be effectively controlled as the installation floor of the sky-bridge increases and acceleration responses can be effectively reduced when the sky-bridge is installed on the mid-stories of the example building.

  • PDF

Effects of Ultrasonic Amplitude on Electrochemical Properties During Cavitation of Carbon Steel in 3.5% NaCl Solution

  • Jang, I.J.;Kim, K.T.;Yoo, Y.R.;Kim, Y.S.
    • Corrosion Science and Technology
    • /
    • v.19 no.4
    • /
    • pp.163-173
    • /
    • 2020
  • Cavitation corrosion in many industrial plants has recently become a serious issue. Cavitation corrosion has generally been investigated using a vibratory method based on ASTM G32 standard, and the test can be divided into direct cavitation and indirect cavitation. Cavitation corrosion test uses the vibration frequency of the horn of 20 kHz with constant peak-to-peak displacement amplitude. In this work, the peak-to-peak amplitude was controlled from 15 ㎛ to 85 ㎛, and electrochemical measurements were obtained during indirect cavitation. The relationship between cavitation corrosion rate and electrochemical properties was discussed. Corrosion steps of carbon steel at the initial stage under cavitation condition in 3.5 % NaCl can be proposed. When the cavitation strength is relatively low, corrosion of the steel is more affected by the electrochemical process than by the mechanical process; but when the cavitation strength is relatively high, corrosion of the steel is affected more by the mechanical process than by the electrochemical process. This work confirmed that the critical ultrasonic amplitude of 0.42 %C carbon steel is 53.8 ㎛, and when the amplitude is less than 53.8 ㎛, the corrosion effect during the cavitation corrosion process is higher than the mechanical effect.

Compressive behavior of built-up open-section columns consisting of four cold-formed steel channels

  • Shaofeng, Nie;Cunqing, Zhao;Zhe, Liu;Yong, Han;Tianhua, Zhou;Hanheng, Wu
    • Steel and Composite Structures
    • /
    • v.45 no.6
    • /
    • pp.907-929
    • /
    • 2022
  • Compression experiments were conducted to investigate the compressive behavior of built-up open-section columns consisting of four cold-formed steel channels (BOCCFSs) of different lengths, thicknesses, and cross-section sizes (OB90 and OB140). The load-displacement curves, failure modes, and maximum compression strength values were analyzed in detail. The tests showed that the failure modes of the OB90 specimens transformed from a large deformation concentration induced by local buckling to flexural buckling with the increase in the slenderness ratio. The failure modes of all OB140 specimens were deformation concentration, except for one long specimen, whose failure mode was flexural buckling. When the slenderness ratios of the specimens were less than 55, the failure modes were controlled by local buckling. Finite element models were built using ABAQUS software and validated to further analyze the mechanical behavior of the BOCCFSs. A parametric study was conducted and used to explore a wide design space. The numerical analysis results showed that when the screw spacing was between 150 mm and 450 mm, the difference in the maximum compression strength values of the specimens was less than 4%. The applicability and effectiveness of the design methods in Chinese GB50018-2002 and AISI-S100-2016 for calculating the compression strength values of the BOCCFSs were evaluated. The prediction methods based on the assumptions produced predictions of the strength that were between 33% to 10% conservative as compared to the tests and the finite element analysis.

Irregular surface output using FDM (Fused Deposition Modeling) 3D printer (FDM(Fused Deposition Modeling) 방식 3D 프린터를 이용한 불규칙한 표면 출력)

  • Lee, Jung-Soo;Cha, Kyung-Chul
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.32 no.1
    • /
    • pp.33-39
    • /
    • 2022
  • As 3D printer-related patents expire and major technologies are disclosed, the price of 3D printers is dropping, creating an environment where you can easily find the product you want. In particular, the cheapest FDM (Fused Deposition Modeling) 3D printer is being used in various fields. The FDM method can be manufactured without collapsing of the shape only by attaching a support under certain conditions when outputting the shape. When printing a shape without a support, the irregular surface that occurs at a certain angle is a defect in the product, but it is considered that it can be used as another fun factor in terms of arts and crafts. In this paper, to obtain such an irregular surface, factors that can affect the output were controlled and only the output angle was tested as a displacement factor. As a result of the experiment, it was possible to obtain an irregular surface without the filament flowing down when printing at an angle of 62° to 70° from the vertical. Also, artificially irregular surfaces were applied to craft products.

A Study on Application and Stability Analysis of Spiral Pipe Nailing System (스파이럴 파이프 네일링 시스템의 안정해석 및 적용성에 관한 연구)

  • Park, Si-Sam;Park, Sung-Chul;Jung, Sung-Pill;Kim, Hong-Taek
    • Journal of the Korean GEO-environmental Society
    • /
    • v.5 no.2
    • /
    • pp.41-49
    • /
    • 2004
  • In this study, a newly modified soil nailing technology named as the SPN (Spiral Pipe Nailing) system, is developed to self drilling method can apply to ground which is hard to keep shape of bore hole. And limit equilibrium analysis with simplified trial wedge method while length ratio and bond ratio being altered was performed to evaluate slope stability considered of tensile strength and bending stiffness. Also, using $FLAC^{2D}$ program, superiority of the SPN system was compared to the GSN (General Soil Nailing) system about an example section. And effects of various factors related to the design of the SPN system, such as the type of drilling method and the bit, are examined throughout a series of the displacement-controlled field pull-out tests. As a result, the SPN system is better than the GSN system in slope stability because of having larger bending stiffness, tensile strength and unit skin friction. And results of simplified trial wedge method are similar to results of TALREN 97 program, commercial limit equilibrium analysis computer software, about an example section. Consequently, it will find out of that the SPN system reduce displacements and settlements in down excavation process as well as to increase the global stability.

  • PDF

Deformation Behavior of Underground Pipe with Controlled Low Strength Materials with Marine Dredged Soil (해양준설토 CLSM을 이용한 지하매설관 변형특성)

  • Lee, Kwan-Ho;Kim, Ju-Deuk;Hyun, Seong-Cheol;Song, Yong-Seon;Lee, Byung-Sik
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.7 no.5
    • /
    • pp.129-137
    • /
    • 2007
  • It is very urgent to research the proper recycling method of marine dredged soil as construction material for environmental conservation. Couple of developed countries have been lots of related researches on recycling of marine dredged soil for marine environmental conservation. This is highly imperative in our country. A small-scaled model test for underground pipe has been conducted on the use of controlled low strength materials with marine dredged soil. The flexible pipe, which is called PVC, was used. Four different testing materials, such as natural sand, insitu-soil, sand-CLSM with marine dredged soil and insitu-soil CLSM with marine dredged soil, were used. The vertical and lateral displacement of pipe with CLSM is one tenth of common granular materials. Also, the use of CSLM showed lower lateral and vertical pressure than that of common granular materials. The main reason is the effect of cement hardening of CLSM. This could increase of the stiffness of pipe with backfill materials. In this study, the data presented show that marine dredged soil and in-situ soil can be successfully used in CLSM and reduce the deformation and earth pressure on flexible pipe.

Bite Force, Occlusal Contact Area and Occlusal Pressure of Patients with Temporomandibular Joint Internal Derangement (측두하악관절 내장증 환자의 교합력, 교합 접촉 면적 및 교합압)

  • Kim, Ki-Seo;Choi, Jong-Hoon;Kim, Seong-Taek;Kim, Chong-Youl;Ahn, Hyung-Joon
    • Journal of Oral Medicine and Pain
    • /
    • v.31 no.3
    • /
    • pp.265-274
    • /
    • 2006
  • Temporomandibular joint (TMJ) internal derangement, especially disc displacement with reduction (DDwR) is the most common TMJ arthropathy and has been thought to do some effects on masticatory performance. Measuring of maximal bite force has been widely used as objective and quantitative method of evaluating masticatory performance, but previous studies showed various results due to various characteristics of subjects and different measuring devices and techniques. In a few studies about the correlation of bite force and temporomandibular disorders (TMD), some authors reported that bite force and masticatory performance would be reduced in patients with TMD because of pain. But the correlation of changes in structure of articular disc and masticatory performance has not been well investigated yet. In this study, to investigate the influences of non-painful disc change on the masticatory performance, we measured the value of maximal bite force, occlusal contact area and occlusal pressure of 39 patients with non-painful DDwR of the TMJ using pressure sensitive film, and compared it with that of 59 controls. The results are summarized as follows: 1. The maximal bite force (P<0.01) and the occlusal contact area (P < 0.05) of the DDwR patients were greater than the controls. 2. There was no significant difference in occlusal pressure between the DDwR patients and the controls (P > 0.05). 3. The maximal bite force of the male group was greater than that of the female group (P < 0.05). However, the occlusal contact area and the occlusal pressure between the male and the female group didn't show significant difference (P > 0.05). From the results above, we can suggest that DDwR could be a factor of changing bite force, but more controlled, large scaled and EMG related further study is needed.