• Title/Summary/Keyword: steel-joint

Search Result 1,348, Processing Time 0.025 seconds

A Study on Adhesive Joints for Composite Driveshafts (복합재료 동력전달축의 접착조인트에 관한 연구)

  • 김진국;이대길;최진경;김일영
    • Composites Research
    • /
    • v.14 no.2
    • /
    • pp.13-21
    • /
    • 2001
  • Substituting composite structures for conventional metallic structures has many advantages because of higher specific stiffness and specific strength of composite materials. In this work, one-piece driveshafts composed of carbon/epoxy and glass/epoxy composites were designed and manufactured for a rear wheel drive automobile satisfying three design specifications, such as static torque transmission capability, torsional buckling and the fundamental natural bending frequency. Single lap adhesive joint was used to join the composite shaft and the aluminum yoke. The torque transmission capability of the adhesively bonded composite shaft was calculated with respect to bonding length and yoke thickness by finite element analysis and compared with the experimental result. Torque transmission capability was based on the Tsai-Wu failure index fur composite shaft and the failure model which incorporated the nonlinear mechanical behavior of aluminum yoke and epoxy adhesive. From the experiments and the finite element analyses, it was found that the static torque transmission capability of the composite driveshaft was highest at the critical yoke thickness, and saturated beyond the critical length. Also, it was found that the one-piece composite driveshaft had 40% weight saving effect compared with a conventional two-piece steel driveshaft.

  • PDF

A Study on the effect of the multi-pass SMAW welding on the characteristic of the underwater welding areas (SMAW 수중 다층용접시 용접부 특성에 관한 연구)

  • 최기용;이상율;이보영;이병훈;이상용;박성두
    • Journal of Welding and Joining
    • /
    • v.16 no.4
    • /
    • pp.55-62
    • /
    • 1998
  • While excellent joint quality has been obtained using dry chamber underwater welding methods, the size limitations imposed by this process restrict its use for underwater construction work. The wet underwater shielded metal-arc welding eliminates this restriction but suffers from poor weld properties by the 1-pass bead-on-plate welding due to the excessive diffusible hydrogen. On the other hand, in the wet underwater welding, it is well known that the quantity of diffusible hydrogen in multi-pass welded parts reduce to less than that in 1-pass welded parts. Therefore, in this paper, welding experiments are made the 3-pass bead-on-plate welds by using TMCP and normalized steel plates and E4301 and cellulose coated electrode. After that, The amounts of the hydrogen absorbed into the 3-pass welded area were measured according to the JIS Z 3118 specification. The microstructural changes as well as the microhardness distribution after the underwater 3-pass welding were also investigated using Vickers microhardness tester and S.E.M and O.M. The results indicated that the quantity of diffusible hydrogen in 3-pass welded areas was reduced little less than a half of one of that in 1-pass welded areas at the specific welding condition. As a result, the cold cracking of 3-pass welded areas decreased by reduced effect of diffusible hydrogen. In the underwater 3-pass welding, the micrography of cold cracking fracture surface showed mainly the cleavage of hydrogen embrittlement.

  • PDF

An Optimization Design of the Insertion Part for Preventing the Screw Thread from Loosening (나사 풀림 방지를 위한 삽입 부품의 설계 최적화)

  • Park, Sangkun
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.16 no.4
    • /
    • pp.2356-2363
    • /
    • 2015
  • This study deals the optimization design with the simulation based design of a coil spring inserted into the lock nut for preventing the screw thread from loosening at the bolted joint when the high-strength steel bolt with the property class of 10.9 is used and the screw torque of 640 to 800 (Nm) is applied. In this study, structural analysis of assembly composed of bolt, nut and coil spring is carried out to evaluate its safety factors on the basis of the equivalent stress with commercial finite element analysis software. And the design strategy to extract the design improvement from these simulation results is established. An iterative process performed with the proposed design strategy is also proposed for improving the performance of the existing design. At the proposed procedure, the feasible design parameters using response surface method are found, and then these parameters are verified to be optimal or not by comparing with the response values and the simulation results obtained from the feasible parameters.

Sensitivity Analysis of Steel Frames Subjected to Progressive Collapse (철골조의 연쇄붕괴 민감도 해석)

  • Park, Jun-Hei;Kim, Jin-Koo;Lee, Tae-Hyung
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.21 no.3
    • /
    • pp.211-216
    • /
    • 2008
  • Recently a lot of researches have been conducted on the progressive collapse of structures which is the total collapse of structures initiated by localized damage. Most of the previous studies on the field of progressive collapse have followed deterministic approach without considering uncertainty involved in design variables, which results in unknown reliability of the analysis results. In this study the sensitivity analyses are carried out with design variables such as yield strength, live load, damping ratio, and elastic modulus on the vertical deflection of the joint from which a column is suddenly removed. The Monte Calro simulation, tornado diagram method, and the first order second moment method(FOSM) are applied for the sensitivity study. According to the nonlinear static analysis results, the vertical deflection is most affected by the variation of yield strength of beams. The nonlinear dynamic analyses show that the behaviour of model structures is highly sensitive to variation of the yield strength of beams and the structural damping ratio.

Analysis of Mechanical Behavior and Fracture Toughness $K_{IC}$ on EGW Welded Joints for High Strength EH36-TMCP Ultra Thick Plate (고강도 극후판 EH36-TMCP강 EGW용접부의 역학적 거동 및 파괴인성 $K_{IC}$에 관한 해석)

  • Bang, Hee-Seon;Bang, Han-Sur;Joo, Sung-Min
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.22 no.6
    • /
    • pp.565-572
    • /
    • 2009
  • This work intends to establish the reliability and fracture toughness $K_{IC}$ criterion of welded joints by EGW for high strength EH36-TMCP ultra thick plate. For this, firstly thermo elasto-plastic analysis has been carried out on two pass X-groove butt joint model to clarify the thermal and mechanical behaviour(residual stress, plastic strain, magnitude of stress and their distribution and production mechanism). Moreover, to establish fracture criterion, analysis of fracture toughness $K_{IC}$ has been performed under the notch machined and residual stress with the load condition on EGW welded joints. A quantitative fracture criterion for EGW welded joints is suggested by using $K_{IC}$.

Fabrication and Characteristics of HTS Field Winding of a 100 hp Synchronous Motor (100마력 동기전동기용 고온초전도 계자권선 제작과 특성)

  • Sohn Myung-Hwan;Baik Seung-Kyu;Lee Eon-Young;Kwon Young-Kil;Jo Young-Sik;Moon Tae-Sun;Kim Yeong-Chun;Kwon Woon-Sik
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.54 no.2
    • /
    • pp.88-93
    • /
    • 2005
  • To develop a 100 hp high temperature superconducting(HTS) motor with high efficiency first in Korea, we fabricated a HTS field winding and test. HTS field winding is composed of sixteen HTS race track shaped coils wound with stainless steel-reinforced Bi-2223 tape conductor by react and wind fabrication method. Nomex paper was used for electrical insulation. Each of four magnet pole assemblies was constructed with four double pancake sub-coils, mechanically stacked and electrically in series. Four magnet assemblies were fixed on an aluminum support structure to make effective heat transfer. The Critical current (Ic) was 41.5A at 77K and self field. However the lowest Ic value of sub-coils was 35A. Joule heat generated by each joints between sub-coils was lower than 1mW at 77K and 34A. And Joule heat generated by the joints between field coils was lower than 10mW at 77K and 34A. Joule heat of the whole field winding was 1W at 77K and 32A. And so, the lowest Ic value of sub-coils was more important than Joule heats generated by all joints. The operating current must be lower than the lowest Ic of all the sub-coils. In this paper, design, construction and testing of HTS field winding, Joule heat generated by the joints, and operating current were discussed.

An experimental study of the behaviour of double sided bolted billet connections in precast concrete frames

  • Gorgun, Halil
    • Steel and Composite Structures
    • /
    • v.29 no.5
    • /
    • pp.603-622
    • /
    • 2018
  • Precast concrete structures are erected from individual prefabricated components, which are assembled on-site using different types of connections. In the present design of these structures, beam-to-column connections are assumed pin jointed. Bolted billet beam to-column connections have been used in the precast concrete industry for many years. They have many advantages over other jointing methods in component production, quality control, transportation and assembly. However, there is currently limited information concerning their detailed structural behaviour under vertical loadings. The experimental work has involved the determination of moment-relative rotation relationships for semi-rigid precast concrete connections in full-scale connection tests. The study reported in this paper was undertaken to clarify the behaviour of such connections under symmetrical vertical loadings. A series of full-scale tests was performed on sample column for which the column geometry and bolt arrangements conformed to successful commercial practice. Proprietary hollow core floor slabs were tied to the beams by 2T25 tensile reinforcing bars, which also provide the in-plane continuity across the connections. The contribution of the floor strength and stiffness to the flexural capacity of the joint is currently neglected in the design process for precast concrete frames. The flexural strength of the connections in the double-sided tests was at least 0.93 times the predicted moment of resistance of the composite beam and slab. The secant stiffness of the connections ranged from 0.94 to 1.94 times the flexural stiffness of the attached beam. In general, the double-sided connections were found to be more suited to a semi-rigid design approach than the single sided ones. The behaviour of double sided bolted billet connection test results are presented in this paper. The behaviour of single sided bolted billet connection test results is the subject of another paper.

A Study on Fracture Property of Adhesive Interface at Tapered Double Cantilever Beam with Inhomogeneous Composite Material due to Loading Conditions of In-plane and Out-plane (면내 및 면외 하중 조건들에 따른 이종 복합 소재를 가진 경사진 이중외팔보에서의 접착계면의 파괴 특성 연구)

  • Lee, Jung-Ho;Kim, Jae-Won;Cheon, Seong-Sik;Cho, Jae-Ung
    • Composites Research
    • /
    • v.33 no.6
    • /
    • pp.401-407
    • /
    • 2020
  • At the engineering and industrial areas, the lightweight composite material has been substituted with the metals, such as steel at the structural parts. This composite material has been applied by the adhesive bonding method, as well as the joint methods with rivets, welds or bolts and nuts. The study on the strength characteristics of adhesive interface is necessarily required in order to apply the method to composite materials. CFRP specimens as the fiber reinforced plastic composites were manufactured easily and this study was carried out. The static experiments were performed under the loading conditions of in-plane and out-plane shears with the inhomogeneous composite TDCB specimens with CFRP, aluminum (Al6061), and aluminum foam (Al-foam). Through the result of this study, the durability on the inhomogeneous composite structure with adhesive interface was investigated by examining the fracture characteristic and the point in time.

Seismic behavior and failure modes of non-ductile three-story reinforced concrete structure: A numerical investigation

  • Hidayat, Banu A.;Hu, Hsuan-Teh;Hsiao, Fu-Pei;Han, Ay Lie;Sosa, Lisha;Chan, Li-Yin;Haryanto, Yanuar
    • Computers and Concrete
    • /
    • v.27 no.5
    • /
    • pp.457-472
    • /
    • 2021
  • Reinforced concrete (RC) buildings in Taiwan have suffered failure from strong earthquakes, which was magnified by the non-ductile detailing frames. Inadequate reinforcement as a consequence of the design philosophy prior to the introduction of current standards resulted in severe damage in the column and beam-column joint (BCJ). This study establishes a finite element analysis (FEA) of the non-ductile detailing RC column, BCJ, and three-story building that was previously tested through a tri-axial shaking table test. The results were then validated to laboratory specimens having the exact same dimensions and properties. FEA simulation integrates the concrete damage plasticity model and the elastic-perfectly plastic model for steel. The load-displacement responses of the column and BCJ specimens obtained from FEA were in a reasonable agreement with the experimental curves. The resulting initial stiffness and maximum base shear were found to be a close approximation to the experimental results. Also, the findings of a dynamic analysis of the three-story building showed that the time-history data of acceleration and displacement correlated well with the shaking table test results. This indicates the FEA implementation can be effectively used to predict the RC frame performance and failure mode under seismic loads.

CONSTRUCTION MANAGEMENT OF TUNNELLING IN SEVERE GROUNDWATER CONDITION

  • Young Nam Lee;Dae Young Kim
    • International conference on construction engineering and project management
    • /
    • 2005.10a
    • /
    • pp.655-661
    • /
    • 2005
  • For a hydro power plant project, the headrace tunnel having a finished diameter of 3.3m was constructed in volcanic rocks with well-developed vertical joint and high groundwater table. The intake facility was located 20.3 km upstream of the powerhouse and headrace tunnel of 20 km in length and penstock of 440 m in height connected the intake and the powerhouse. The typical caldera lake, Lake Toba set the geology at the site; the caving of the ground caused tension cracks in the vertical direction to be developed and initial stresses at the ground to be released. High groundwater table(the maximum head of 20 bar) in the area of well-connected vertical joints delayed the progress of tunnel excavation severely due to the excessive inflow of groundwater. The excavation of tunnel was made using open-shield type TBM and mucking cars on the rail. High volume of water inflow raised the water level inside tunnel to 70 cm, 17% of tunnel diameter (3.9 m) and hindered the mucking of spoil under water. To improve the productivity, several adjustments such as modification of TBM and mucking cars and increase in the number of submersible pumps were made for the excavation of severe water inflow zone. Since the ground condition encountered during excavation turned out to be much worse, it was decided to adopt PC segment lining instead of RC lining. Besides, depending on the conditions of the water inflow, rock mass condition and internal water pressure, one of the invert PC segment lining with in-situ RC lining, RC lining and steel lining was applied to meet the site specific condition. With the adoption of PC segment lining, modification of TBM and other improvement, the excavation of the tunnel under severe groundwater condition was successfully completed.

  • PDF