• Title/Summary/Keyword: structural rotation

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STRESS DISTRIBUTION OF THREE NITI ROTARY FILES UNDER BENDING AND TORSIONAL CONDITIONS USING 3-DIMENSIONAL FINITE ELEMENT ANALYSIS (세가지 니켈 티타늄 파일의 휨과 비틀림 조건에서의 응력 분포에 관한 3차원 유한요소 연구)

  • Kim, Tae-Oh;Lee, Chan-Joo;Kim, Byung-Min;Park, Jeong-Kil;Hur, Bock;Kim, Hyeon-Cheol
    • Restorative Dentistry and Endodontics
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    • v.33 no.4
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    • pp.323-331
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    • 2008
  • Flexibility and fracture properties determine the performance of NiTi rotary instruments. The purpose of this study was to evaluate how geometrical differences between three NiTi instruments affect the deformation and stress distributions under bending and torsional conditions using finite element analysis. Three NiTi files (ProFile .06 / #30, F3 of ProTaper and ProTaper Universal) were scanned using a Micro-CT. The obtained structural geometries were meshed with linear, eight-noded hexahedral elements. The mechanical behavior (deformation and von Mises equivalent stress) of the three endodontic instruments were analyzed under four bending and rotational conditions using ABAQUS finite element analysis software. The nonlinear mechanical behavior of the NiTi was taken into account. The U-shaped cross sectional geometry of ProFile showed the highest flexibility of the three file models. The ProTaper, which has a convex triangular cross-section, was the most stiff file model. For the same deflection, the ProTaper required more force to reach the same deflection as the other models, and needed more torque than other models for the same amount of rotation. The highest von Mises stress value was found at the groove area in the cross-section of the ProTaper Universal. Under torsion, all files showed highest stresses at their groove area. The ProFile showed highest von Mises stress value under the same torsional moment while the ProTaper Universal showed the highest value under same rotational angle.

Cyclic Loading Test for Beam-to-Column Connections of Concrete Encased CFT Column (콘크리트피복충전 각형강관 기둥-보 접합부의 주기하중 실험)

  • Park, Hong Gun;Lee, Ho Jun;Park, Sung Soon;Kim, Sung Bae
    • Journal of Korean Society of Steel Construction
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    • v.26 no.1
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    • pp.55-68
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    • 2014
  • In this study, the beam-to column connections of concrete-encased-and-filled steel tube columns were tested under cyclic loading. Two specimens using steel beams and two specimens using precast concrete beams were tested. The dimension of the column cross section was $670mm{\pm}670mm$. The beam depths were 488mm and 588mm for the steel beams and 700mm for the precast concrete beams. The longitudinal bar ratios of the precast concrete beams were 1.1% and 1.5%. For the connections to the steel beams, continuity plates were used in the tube columns. For the connections to the PC beams, couplers were used for beam re-bar connections. The test results showed that except for a specimen, deformation capacities of the specimens were greater than 4% rotation angle, which is the requirement for the Special Moment Frame. Particularly, specimens using precast concrete beam showed excellent performances in the strength, deformation, and energy dissipation.

Structural Performance of Joints for Partial Reinforced Beam Using GFRP Laminated Plate and Cylindrical Reinforced LVL Column (GFRP적층판을 활용한 보강보부재와 원통형 단판적층기둥재 접합부의 내력 성능평가)

  • Song, Yo-Jin;Jung, Hong-Ju;Lee, Jung-Jae;Suh, Jin-Suk;Park, Sang-Bum;Hong, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.3
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    • pp.282-289
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    • 2014
  • After being laminated with a combination of glass fiber reinforced plastic and plywood, the GFRP laminated plate was densificated for 1 hour at $150^{\circ}C$ with pressure of $1.96N/mm^2$. A partial reinforced beam was produced by attaching the 5 GFRP laminated plates to the joint of glulam and the column. In addition, the column to beam joint was produced by using reinforced laminated wooden pin which was made of GFRP sheet and plywood, fiber glass reinforced cylindrical-LVL column. The joint was made of round log, glulam and drift pin as the reference specimen, and its moment resistance was evaluated. As a result, the strength performance of specimens with partial reinforced beams were 1.8 times stronger than the reference specimen on average. Furthermore, rupture was neither occurred on partial reinforced beam nor column. Toughness and stiffness of joints were also fine. The GFRP sheet reinforced laminated plate showed better reinforcement effect than GFRP textile reinforced one. GFRP sheet was inserted into each layer of laminate, and it showed good condition in rotation-angle and strength, therefore it is the most appropriate to reinforce the part of the beam.

A Study on the Geometric Deformation Measurement of Structures by Collinearity Condition (공선조건에 의한 구조물의 기하학적 변형해석에 관한 연구)

  • 강준묵;오원진;이진덕;한승희
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.4 no.2
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    • pp.77-87
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    • 1986
  • As for the deformation measurement of structure, there are many controversial points in using the methods by the strain guage, inclinometer, bial guage, and geodetic method because of the difficulty of instrument setting and the problem in the degree of accuracy of the results as well as in the economical aspect. Therefore, to verify the superiority of the Close- Range Photogrammetry method for the structural deformation measurement, the result of load deformation on the model structure, which was made using the Close-Range Photogrammetry method was compard with the results which was made using the methods of dial guage, precision level, and triangulation. In addition to that, to consider the general problem which would happen when C. R. P method was applied to the practical structure. The elements of C. R. P method like camera rotation angle ($\psi$,$\omega$), exposure elevation (Z$_{L}$), and angle of inclined base line ($\theta$) were experimented, and their specificities were reconsidered. As a result, the application of C. R. P method to the general structure is expected to be increased not only in the aspect of accuracy but in the economical aspect.t.

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Anatomical Characteristics of Korean Phyllostachys pubescens by Age (국내산 맹종죽의 죽령별 해부학적 특성)

  • Jeon, Woo-Seok;Byeon, Hee-Seop;Kim, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.3
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    • pp.231-240
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    • 2018
  • Bamboo is one of the major biomass resources that have many advantages such as fast growing, easy cultivation, short rotation, and a relatively lower price. In this study, the anatomical characteristics of Moso bamboo (Phyllostachys pubescens) by age from one-year-old to five-year-old were examined by optical and scanning electron microscopy. Also, the crystalline properties such as relative crystallinity and crystallite width were investigated by an X-ray diffraction method. In one-year-old bamboo xylem, a few vascular bundles showed missing bundle sheath in near the intercellular space. Moreover, one-year-old bamboo had the shortest fiber length and the smallest values in vessel diameter, width of vascular bundle, and thickness of inner layer. One-year-old bamboo also showed the smallest values in the crystallinity and crystallite width. Near epidermis samples had longer fiber length and greater vascular bundle spacing than near pith samples. Relative crystallinity and crystallite width near the epidermis were also higher than near the pith. This study revealed significant differences in qualitative and quantitative anatomical characteristics between one-year-old and two-year- or more old Moso bamboos. It is concluded that the structural differences by bamboo age can be used to differentiate the characteristics of juvenile and mature bamboo.

Structural, Magnetic, and Magneto-Optic Properties of Nonstoichiometric Bismuth-Substituted Yttrium lron Gamet Films Prepared by Pyrolysis (열분해법에 의해 제조한 비화학양론조성을 갖는 비스머스 치환 이트리움-철-가네트 박막의 구조적, 자기적 및 자기광학적 특성)

  • Jae-Kyong Cho
    • Journal of the Korean Magnetics Society
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    • v.4 no.1
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    • pp.39-43
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    • 1994
  • Polycrystalline nonstoichiometric bismuth-substituted yttrium iron garnet films with cation ratios of Bi:Y:Fe=1.5+u:1.5:5 and Bi:Y:Fe=1.5:1.5+v:5, where $-0.7{\leq}u{\leq}1.0$ and $-0.7{\leq}v{\leq}1.3$, have been prepared by pyrolysis. The crystal phases formed in these films at various temperatures have been analyzed by high power x-ray diffractometry (XRD). The saturation ma- gnetization, the Curie temperatures, and the Faraday rotation at the wavelength of 633 nm have been measured as a function of u and v. The XRD studies indicated that the bismuth and yttrium depleted (u < 0 and v < 0) films consisted of the mixed phases of garnet and impunity. While in the bismuth and ytrium overdosed films, no impurity lines were observed over a wide composition range of $0{\leq}u{\leq}0.5$ and $0{\leq}v{\leq}0.7$. The observed magnetic and magneto-optic data of these overdosed films, however, could only be reasonably explained by assuming the presence of samll amount of spurious phases, not detectable by the XRD.

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The Effect of Spiral Balance Taping on Postoperative Sequelae in Breast Cancer : Case study (스파이랄 발란스 테이핑이 유방암 환자의 수술 후 후유증에 미치는 영향 : 사례연구)

  • Su-Ji Kang;Dae-Hee Lee;Cheul Jang;Back-Vin Lim
    • Journal of The Korean Society of Integrative Medicine
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    • v.12 no.3
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    • pp.37-47
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    • 2024
  • Purpose : Cancer survivors often suffer from postoperative sequelae. the diagnosing and provision of manual therapy using spiral taping significantly improves the quality of life of cancer patients. The aim of this case study is to investigate the immediate effects of spiral taping on pain, range of motion (ROM), chemotherapy-induced peripheral neuropathy (CIPN), and lymphedema following breast cancer surgery. Methods : The taping techniques were performed as follows by spiral taping. The measurements were taken before, in the middle, and after taping using a mobile phone camera, tape measure, and a numerical rating score (NRS). The evaluation employed a single-group pre-post design based on a primitive experimental design. Results : Out of four patients, all four exhibited Reverse circle flow energy (RCFE), Passive cervical right (Rt) rotation test, anterior-posterior movement pattern, nerve type (+), cold energy (CE), sangcho acupuncture point, blood clot, hwal point. Comparing before and after treatment, almost all values were reduced to zero after treatment in terms of pain complaints. The lack of range of motion (ROM) caused by the shortened tissue after surgery did not increase. The range of motion (ROM) lost due to pain returned to normal. The circumference of lymphedema did not show a tendency. The symptoms of CIPN improved. Conclusion : There was a significant change in joint range of motion, with pain decreasing, but there were structural limitations in the tissue due to total resection, and the chemotherapy-induced peripheral neuropathy scale. It was effectively treated surgical site pain, axillary membrane syndrome-induced pain, and unexplained pain. While there was a treatment effect for lymphedema in the evaluation of circumference values, there was no significant change in circumference. There was a significant effect on chemotherapy-induced peripheral neuropathy, particularly in treating numbness in the feet, which is a side effect of TC anticancer drugs. This case study found that spiral balance taping provides a rapid therapeutic effect for most side effects in patients who have undergone total breast cancer resection. However, the generalization is limited due to the small sample size, and further research is needed to determine the extent to which the effects of one treatment are maintained.

The Effect of Consumer's Perceptual Characteristics for PB Products on Relational Continuance Intention: Mediated by Brand Trust and Brand Equity (PB상품에 대한 소비자의 지각특성이 관계지속의도에 미치는 영향: 브랜드신뢰 및 브랜드자산을 매개로 한 정책적 접근)

  • Lim, Chaekwan
    • Journal of Distribution Research
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    • v.17 no.5
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    • pp.85-111
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    • 2012
  • Introduction : The purpose of this study was to examine the relationship between perceptual characteristics of consumers and intent of relational continuance for PB(Private Brand) products in discount stores. This study was conducted as an empirical study based on survey. For the empirical study, factors of PB products as characteristics perceived by consumers such as perceived quality, store image, brand image and perceived value were deduced from preceding studies. The effect of such factors on intent of relational continuance mediated by brand trust and brand equity of PB products was structurally examined. Research Model : Based on theory analysis and hypotheses, constructed a Structural Equation Model(SEM). The research model is shown in Figure 1. Research Method : This paper is based on s qualitative study of selected literature and empirical data. The survey for empirical study was carried out on consumers in Gyeonggi and Busan between January 2012 and May 2012. 300 surveys were distributed and 253 (84.3%) of them were returned. After excluding omissions and insincere responses, 245 surveys (81.6%) were used for final analysis as effective samples. Result : First of all, the Reliability was carried out for instrument used. The lower limit of 0.7 for Cronbach's Alpha as suggested by Hair et al. (1998). And Construct validity was established by carrying out exploratory factor analysis by Varimax rotation for all. Four factor result for the consumer's perceptual characteristics of PB Products, two mediating factors and one dependent factor. All constructs included in research framework have acceptable validity and reliability. Table 1 shows the factor loading, eigen value, explained variance and Cronbach's alpha for each factor. In order to assure validity of constructs, I implemented Confirmatory Factor Analysis (CFA), using AMOS 20.0. In confirmatory factor analysis, researcher can take control over the specification of indicators for each factor by hypothesizing that a specific factor is loaded with the relevant indicators. Moreover, CFA is particularly useful in the validation of scale for the measurement of specific construct. CFA result summarized Table 2 shows that the fit measures of all constructs fulfill the recommended level and loadings are significant. To test causal relationship between constructs in the research model, used AMOS 20.0 that provides a graphic module as method for analysing Structural Equation Modeling. The result of hypothesis test is shown in Table 3. As a result of empirical study, perceived quality, brand image and perceived value as selected attributes for PB products showed significantly positive (+) effect on brand trust and brand equity. Furthermore, brand trust and brand equity showed significantly positive (+) effect on intent of relational continuance. However, store image of discount stores selling the PB products was analyzed to have positive (+) effect on brand trust and no significant effect on brand equity. Discussion : Based on the results of this study, the relationship between overall quality, store image, brand image and value perceived by consumers about PB products and intent of relational continuance was structurally verified as being mediated by brand trust and brand equity. Looking at the results, a strategic approach that maximizes brand trust and equity value for PB products by large discount stores is required on top of basic efforts to improve quality, brand image and value of PB products in order to maximize consumer's intent of relational continuance and to continuously attract repeated purchase of products.

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Evaluating Impact Resistance of Externally Strengthened Steel Fiber Reinforced Concrete Slab with Fiber Reinforced Polymers (섬유 보강재로 외부 보강된 강섬유 보강 콘크리트 슬래브의 충격저항성능 평가)

  • Yoo, Doo-Yeol;Min, Kyung-Hwan;Lee, Jin-Young;Yoon, Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.24 no.3
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    • pp.293-303
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    • 2012
  • Recently, as construction technology improved, concrete structures not only became larger, taller and longer but were able to perform various functions. However, if extreme loads such as impact, blast, and fire are applied to those structures, it would cause severe property damages and human casualties. Especially, the structural responses from extreme loading are totally different than that from quasi-static loading, because large pressure is applied to structures from mass acceleration effect of impact and blast loads. Therefore, the strain rate effect and damage levels should be considered when concrete structure is designed. In this study, the low velocity impact loading test of steel fiber reinforced concrete (SFRC) slabs including 0%~1.5% (by volume) of steel fibers, and strengthened with two types of FRP sheets was performed to develop an impact resistant structural member. From the test results, the maximum impact load, dissipated energy and the number of drop to failure increased, whereas the maximum displacement and support rotation were reduced by strengthening SFRC slab with FRP sheets in tensile zone. The test results showed that the impact resistance of concrete slab can be substantially improved by externally strengthening using FRP sheets. This result can be used in designing of primary facilities exposed to such extreme loads. The dynamic responses of SFRC slab strengthened with FRP sheets under low velocity impact load were also analyzed using LS-DYNA, a finite element analysis program with an explicit time integration scheme. The comparison of test and analytical results showed that they were within 5% of error with respect to maximum displacements.

Aeromagnetic Interpretation of the Southern and Western Offshore Korea (한국 서남근해에 대한 항공자력탐사 해석)

  • Baag Czango;Baag Chang-Eob
    • The Korean Journal of Petroleum Geology
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    • v.2 no.2 s.3
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    • pp.51-57
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    • 1994
  • Analysis of the aeromagnetic data aquired by US Navy in the year 1969 permits us to predict a new sedimentary basin, Heugsan Basin, south of the known Gunsan Basin in Block Ⅱ. The basin appears to consist of three sub-basins trending NNW-SSE. The results of our analysis provide not only an independent assessment of the Gunsan Basin, but also new important information on the tectonic origin and mechanism for the two basins as well as for the entire region. The basin forming tectonic style is interpreted as rhombochasm associated with double overstepped left-lateral wrench faults. From the magnetic evidence, a few NE-SW trending major onshore faults are extended to the study area. We also interpreted the nature of the faults to be left-lateral wrenches. This new gross structural style is consistent with the results of recent Yeongdong Basin analysis by Lee. The senses of fault movement are also supported by the paleomagnetic evidence that the Philippine Sea had experienced an 80-degree clockwise rotation since the Eocene. Based on a 2 $\frac{1}{2}$ model study the probable maximum thickness of the sediments in the Gunsan Basin is approximately 7500 meters. We believe that the new Heugsan Basin was left unidentified because a high velocity layer may be overlying the basin. Because the overall structural configuration of the Heugsan Basin appears to be favorable for hydrocarbon accumulation, a detailed airborne magnetic survey is recommended in the area in order to verify the magnetic expression of this thick basin. A detailed subsequent marine gravity survey is also recommended in order to delineate the sedimentary section and to acquire supplemental data to the magnetic method only if an overlying high velocity layer is confirmed. Otherwise a high energy source seismic survey may be more effective.

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