• Title/Summary/Keyword: Middle Beam

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A Study on Dynamic Behavior of Simply Supported Fluid Flow Pipe with Crack and Moving Mass (크랙과 이동질량을 가진 유체유동 단순지지 파이프의 동특성에 관한 연구)

  • Yoon, Han-Ik;Jin, Jong-Tae;Son, In-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.4
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    • pp.419-426
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    • 2004
  • In this paper, studied about the effect of open crack and the moving mass on the dynamic behavior of simply supported pipe conveying fluid. The equation of motion is derived by using Lagrange's equation. The influences of the velocity of moving mass, the velocity of fluid flow and a crack have been studied on the dynamic behavior of a simply supported pipe system by numerical method. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. Therefore, the crack is modelled as a rotational spring. Totally, as the velocity of fluid flow is increased, the mid-span deflection of simply supported pipe conveying fluid is increased. The position of the crack is located in the middle point of the pipe, the mid-span deflection of simply supported pipe presents maximum deflection.

Characteristic features of fungus ball in the maxillary sinus and the location of intralesional calcifications on computed tomographic images: A report of 2 cases

  • Lee, Jae-Hoon;Lee, Byung-Do
    • Imaging Science in Dentistry
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    • v.50 no.4
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    • pp.377-384
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    • 2020
  • This report presents 2 cases of sinus fungus ball and describes the characteristic radiographic features of fungus ball in the maxillary sinus. Two female patients, aged 62 and 40 years, sought consultations at a dental hospital for the treatment of dental implants and tooth pain, respectively. Panoramic radiography and small field-of-view(FOV) cone-beam computed tomography (CBCT) did not provide detailed information for the radiographic diagnosis of fungus ball due to the limited images of the maxillary sinus. Additional paranasal sinus computed tomographic images showed the characteristic features of fungus ball, such as heterogeneous opacification and intralesional calcification of the maxillary sinus. The calcified materials of the fungus balls were located in the middle and superior regions of the maxillary sinus. It is necessary to use large-FOV CBCT for the detection of calcified materials in the upper maxillary sinus to confirm the diagnosis of fungus ball.

Writing ADM Network Diagram of Frame Work for the Precast Concrete Public Apartment Building Construction Management (보-기둥구조 PC공동주택 시공관리를 위한 골조공사 ADM공정표 작성)

  • Kim, Ki-Ho;Kim, MIn-Jun;Kim, Jin-Won;Lee, Dong-Gun;Sohn, Jeong-Rak;Lee, Bum-Sik
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.221-222
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    • 2022
  • In this study, the work flow of the construction process was analyzed based on construction monitoring for a building of the middle size beam-column system Precast Concrete(PC) apartment building supplied by LH, and the Arrow Daigram Method(ADM) network diagram of its construction was written. The results of this study are judged to be able to improve productivity by using the PC structure apartment building construction plan to calculate a reasonable construction period and prepare a process management method for the PC structure frame construction.

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Study on mechanical behaviors of cable-supported ribbed beam composite slab structure during construction phase

  • Qiao, W.T.;An, Q.;Wang, D.;Zhao, M.S.
    • Steel and Composite Structures
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    • v.21 no.1
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    • pp.177-194
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    • 2016
  • The cable-supported ribbed beam composite slab structure (CBS) is a new type of pre-stressed hybrid structure. The standard construction method of CBS including five steps and two key phases are proposed in this paper. The theoretical analysis and experimental research on a 1:5 scaled model were carried out. First, the tensioning construction method based on deformation control was applied to pre-stress the cables. The research results indicate that the actual tensile force applied to the cable is slightly larger than the theoretical value, and the error is about 6.8%. Subsequently, three support dismantling schemes are discussed. Scheme one indicates that each span of CBS has certain level of mechanical independence such that the construction of a span is not significantly affected by the adjacent spans. It is shown that dismantling from the middle to the ends is an optimal support dismantling method. The experimental research also indicates that by using this method, the CBS behaves identically with the numerical analysis results during the construction and service.

Rational analysis model and seismic behaviour of tall bridge piers

  • Li, Jianzhong;Guan, Zhongguo;Liang, Zhiyao
    • Structural Engineering and Mechanics
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    • v.51 no.1
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    • pp.131-140
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    • 2014
  • This study focuses on seismic behaviour of tall piers characterized by high slender ratio. Two analysis models were developed based on elastic-plastic hinged beam element and elastic-plastic fiber beam element, respectively. The effect of the division density of elastic-plastic hinged beam element on seismic demand was discussed firstly to seek a rational analysis model for tall piers. Then structural seismic behaviour such as the formation of plastic hinges, the development of plastic zone, and the displacement at the top of the tall piers were investigated through incremental dynamic analysis. It showed that the seismic behaviour of a tall pier was quite different from that of a lower pier due to higher modes contributions. In a tall pier, an additional plastic zone may occur at the middle height of the pier with the increase of seismic excitation. Moreover, the maximum curvature reaction at the bottom section and maximum lateral displacement at the top turned out to be seriously out of phase for a tall pier due to the higher modes effect, and thus pushover analysis can not appropriately predict the local displacement capacity.

Analytical Study on Strength Resistance of Steel Beams with Stiffened Ends by Reinforced Concrete -difference of behavior with fixing plate- (복합보의 내력성능에 관한 연구 -정착판의 설치에 의한 거동의 차이-)

  • Kim, Seong Eun
    • Journal of Korean Society of Steel Construction
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    • v.12 no.6
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    • pp.681-690
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    • 2000
  • Recently, a long span is often required for the spacious building. Therefore the increase of stiffness is necessary to prevent floor vibration and control deformation of the building under earthquake and wind loads. For this purpose, steel beams with stiffened ends by reinforced concrete are effective. To realize such an effective reinforcement method, the smoothening of bending and shear stress transmission at the boundaries between middle-part of the steel beam and both end-parts of the steel beam with stiffened ends by reinforced concrete is required. Therefore, the fixed plate was installed at the boundary with the view of transferring the stress smoothly. This paper evaluates the method of effective transmission of bending and shear stress through the numerical analysis that is based on advanced experimental tests.

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A Study on the 'Perpendicular crossing Dori(Purlin)' Structure of the Ddeulzip(Courthouse) in Andong Cultural Area (안동문화권(安東文化圈) 뜰집의 '직교(直交)도리' 구조(構造)에 관한 연구(硏究))

  • Kim, Hwa-Bong
    • Journal of architectural history
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    • v.9 no.2 s.23
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    • pp.7-17
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    • 2000
  • The purpose of this study is the analysis of 'perpendicular crossing Dori' with a structural character of Ddeulzip in Andong cultural area. There are many structural methods to solve the problems of Ddeuljip which is connected space in the rectangular type. There are 'Slope Base', 'Woosangak' roof, 'Seosangak' roof, and '4 beam roof framing' Moreover, they have been used 'perpendicular crossing Dori'. Its characters are as follows ; 1. The 'perpendicular crossing Dori' structure is occurred in different depth of width and length space of 'ㄱ' typed plan. At that time the beam of width is crossed in the middle of the beam of length without the order under them. 2. The 'perpendicular crossing Dori' structure is the method of free depth of width in regular distance of column which is different from general usage of balcony order. 3. The 'perpendicular crossing Dori' structure is founded north-western area of Andong Cultural Area(Bonghwa, Andong, Youngju, and Yeacheun). The best old sample was in Andong(16C) and the next is Yeacheun(17C) and the last is Bonghwa(18C). 4. The frequency in use of roof type of 'perpendicular crossing Dori' structure is 64% of 'Seosangak' and 36% of 'Woosangak'. The sample of 'Woosangak' house of 'perpendicular crossing Dori' structure is concentrated in Bonghwa. 5. The best merit of the 'perpendicular crossing Dori' structure is usage of double swing window in front of Anbang, It is the spacial success which overcomes the structural limits. And it is the structural rationality.

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An analytical-numerical procedure for cracking and time-dependent effects in continuous composite beams under service load

  • Chaudhary, Sandeep;Pendharkar, Umesh;Nagpal, A.K.
    • Steel and Composite Structures
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    • v.7 no.3
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    • pp.219-240
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    • 2007
  • An analytical-numerical procedure has been presented in this paper to take into account the nonlinear effects of concrete cracking and time-dependent effects of creep and shrinkage in the concrete portion of the continuous composite beams under service load. The procedure is analytical at the element level and numerical at the structural level. The cracked span length beam element consisting of uncracked zone in middle and cracked zones near the ends has been proposed to reduce the computational effort. The progressive nature of cracking of concrete has been taken into account by division of the time into a number of time intervals. Closed form expressions for stiffness matrix, load vector, crack lengths and mid-span deflection of the beam element have been presented in order to reduce the computational effort and bookkeeping. The procedure has been validated by comparison with the experimental and analytical results reported elsewhere and with FEM. The procedure can be readily extended for the analysis of composite building frames where saving in computational effort would be very considerable.

Assessment of the Thickness of the Roof of the Glenoid Fossa Using Cone Beam Computed Tomography in Orthognathic Surgery Patients: A Preliminary Study

  • Park, Hyun-Jeong;Seo, Yo-Seob;Lim, Sung-Hoon;Ryu, Ji-Won
    • Journal of Oral Medicine and Pain
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    • v.44 no.4
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    • pp.154-159
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    • 2019
  • Purpose: The aim of this study was to assess the change in thickness of the roof of the glenoid fossa (RGF) in patients undergoing orthognathic surgery using cone-beam computed tomography (CBCT) images. Methods: This retrospective study measured the thickness of the RGF in 19 patients (10 males, 9 females) who underwent orthognathic surgery at Chosun University Dental Hospital. The thickness of the RGF was measured perpendicularly between the 'glenoid fossa line' and 'middle cranial fossa line' on parasagittal and paracoronal reconstructions. Results: The mean RGF thickness increased from 0.83±0.44 mm to 0.86±0.46 mm after surgery. The average change in thickness of the RGF was 0.17±0.18 mm. The thickness of the RGF in the temporomandibular joint (TMJ) showed no significant difference by sex, and the change in thickness of the TMJ did not vary by surgical method. Conclusions: We found that the thickness of the RGF increased after orthognathic surgery, as revealed by CBCT. Further studies including larger numbers of subjects and long-term follow-up are needed to confirm the results of this study.

Use of cone-beam computed tomography and three-dimensional modeling for assessment of anomalous pulp canal configuration: a case report

  • Sinanoglu, Alper;Helvacioglu-Yigit, Dilek;Mutlu, Ibrahim
    • Restorative Dentistry and Endodontics
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    • v.40 no.2
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    • pp.161-165
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    • 2015
  • Three-dimensional (3D) reconstruction of cone-beam computed tomography (CBCT) scans appears to be a valuable method for assessing pulp canal configuration. The aim of this report is to describe endodontic treatment of a mandibular second premolar with aberrant pulp canal morphology detected by CBCT and confirmed by 3D modeling. An accessory canal was suspected during endodontic treatment of the mandibular left second premolar in a 21 year old woman with a chief complaint of pulsating pain. Axial cross-sectional CBCT scans revealed that the pulp canal divided into mesiobuccal, lingual, and buccal canals in the middle third and ended as four separate foramina. 3D modeling confirmed the anomalous configuration of the fused root with a deep lingual groove. Endodontic treatment of the tooth was completed in two appointments. The root canals were obturated using lateral compaction of gutta-percha and root canal sealer. The tooth remained asymptomatic and did not develop periapical pathology until 12 months postoperatively. CBCT and 3D modeling enable preoperative evaluation of aberrant root canal systems and facilitate endodontic treatment.