• Title, Summary, Keyword: 복합하중

Search Result 1,262, Processing Time 0.041 seconds

The Proposition of Efficient Nonlinear Solution Technique for Space Truss (공간 트러스에 대한 효율적인 비선형 해석 기법 제안)

  • 석창목;권영환
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.15 no.3
    • /
    • pp.481-490
    • /
    • 2002
  • The purpose of this paper is to evaluate the efficiency of various solution techniques and propose new efficient solution techniques for space trusses. Solution techniques used in this study are three load control methods (Newton-Raphson Method, modified Newton-Raphson Method, Secant-Newton Method), two load-displacement control methods(Arc-length Method, Work Increment Control Method) and three combined load-displacement control methods(Combined Arc-length Method I , Combined Arc-length MethodⅡ, Combined Work Increment Control Method). To evaluate the efficiency of these solution techniques, we must examine accuracy of their solutions, convergences and computing times of numerical examples. The combined load-displacement control methods are the most efficient in the geometric nonlinear solution techniques and in tracing post-buckling behavior of space truss. The combined work increment control method is the most efficient in tracing the buckling load of spate trusses with high degrees of freedom.

Variation of Dynamic Characteristics of Composite Plates Subjected to Electromagnetic and Thermal Fields via Piezoelectric Control (전자기장과 열하중을 받는 복합재료 평판의 압전제어에 따른 동특성 변화)

  • Park, Sang-Yun;Song, Ohseop
    • Composites Research
    • /
    • v.29 no.6
    • /
    • pp.379-387
    • /
    • 2016
  • Structural model of laminated composite plate based on the first order shear deformation theory and subjected to a combination of piezoelectric, electromagnetic and thermal fields is established. Coupled equations of motion are derived via Hamilton's principle on the basis of electromagnetic and piezoelectric equations which are involved in constitutive equations. Proportional control and velocity feedback control logics are applied via boundary control moments and forces. Variations of dynamic chasracteristics of composite plate with collocated piezoelectric sensor and actuators, electromagnetic field and temperature gradient are investigated and it reveals that dynamic characteristics of structure can be effectively controlled by utilizing the piezoelectric effect and ply angles of fiber reinforced composites.

A Study on Hybrid Wall System on Connection Type of Coupling Beam (커플링 보의 접합방식에 따른 복합 벽체 시스템에 관한 연구)

  • Yun, Hyun-Do;Park, Wan-Shin;Han, Byung-Chan;Yun, Yeo-Jin
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.7 no.4
    • /
    • pp.201-208
    • /
    • 2003
  • The Hybrid Wall System(HWS) building composed of center core reinforced concrete walls and exterior steel frame has open space around the center core walls. It is necessary to develop design methodologies for the HWS building that the coupled shear walls withstand the most of lateral load and expect the most energy dissipation at the coupling beams and at wall foots. Major factors considered in this paper are connection type of coupling beams and scale of story. The studies of the system are investigated in terms of shear force, overturning moment, maximum lateral displacement, story drift ratio, and dynamical characteristics under the action of vertical and lateral forces such as wind and seismic loads.

Evaluation of the Impact Behavior of Inline Disk Wheel Made of Carbon Fiber Reinforced Composites (탄소섬유 강화 복합재로 구성된 인라인 디스크 휠의 충격거동 평가)

  • Kwon, Hye-In;Lee, Sang-Jin;Shin, Kwang-Bok
    • Composites Research
    • /
    • v.29 no.2
    • /
    • pp.73-78
    • /
    • 2016
  • In this paper, The concept of a wheel with carbon fiber composite is to replace the conventional material used for a wheel hub, such as plastic, with a disk-type hub made of carbon fabric and epoxy resin. The impact load from the ground under real conditions was considered; a low-velocity impact test was conducted to evaluate the impact performance of the carbon wheel and compare it with that of a conventional plastic wheel. This study applied a 70 J impact load as a test condition. The impact energy was controlled in the test by adjustment of height and weight of impactor. The use of a carbon disk wheel hub was confirmed to reduce weight and generate an excellent repulsive force at low energy under conditions similar to real driving conditions. The results showed that the maximum load increased proportionally depending on the impact load, but the growth of the maximum load was reduced at a 20 J impact load and tended to decrease at a 45 J impact load. The carbon wheel showed excellent properties ; the level of rebounding was 35.3% and 19.1% of the total impact energy at impact loads of 5 J and 10 J, respectively. On the other hand, the carbon disk wheel rebounded less than 5% of the total energy due to crack generation of the thin carbon hub for impact loads of more than 20 J.

Limit Loads for Pipe Bends under Combined Pressure and in-Plane Bending Based on Finite Element Limit Analysis (압력과 모멘트의 복합하중을 받는 곡관에 대한 유한요소 한계하중 해석)

  • Oh Chang-Sik;Kim Yun-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.30 no.5
    • /
    • pp.505-511
    • /
    • 2006
  • In the present paper, approximate plastic limit load solutions fur pipe bends under combined internal pressure and bending are obtained from detailed three-dimensional (3-D) FE limit analyses based on elastic-perfectly plastic materials with the small geometry change option. The present FE results show that existing limit load solutions for pipe bends are lower bounds but can be very different from the present FE results in some cases, particularly for bending. Accordingly closed-form approximations are proposed for pipe bends under combined pressure and in-plane bending based on the present FE results. The proposed limit load solutions would be a basis of defective pipe bends and be useful to estimate non-linear fracture mechanics parameters based on the reference stress approach.

Limit Loads for Pipe Bends under Combined Pressure and in-Plane Bending Based on Finite Element Limit Analysis (압력과 모멘트의 복합하중을 받는 곡관에 대한 유한요소 한계하중 해석)

  • Oh C.S.;Kim Y.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.401-402
    • /
    • 2006
  • In the present paper, approximate plastic limit load solutions for pipe bends under combined internal pressure and bending are obtained from detailed three-dimensional (3-D) FE limit analyses based on elastic-perfectly plastic materials with the small geometry change option. The present FE results show that existing limit load solutions for pipe bends are lower bounds but can be very different from the present FE results in some cases, particularly for bending. Accordingly closed-form approximations are proposed for pipe bends under combined pressure and in-plane bending based on the present FE results. The proposed limit load solutions would be a basis of defective pipe bends and be useful to estimate non-linear fracture mechanics parameters based on the reference stress approach.

  • PDF

An Investigation on the Strength of Insert Joints of Composite-Honeycomb Sandwich Structures (복합재 -하니콤 샌드위치 구조물의 인써트 조인트 강도 특성 연구)

  • Choi, Ji-Young;Song, Keun-Il;Choi, Jin-Ho;Kim, Kwang-Soo;Jang, Young-Soon;Kweon, Jin-Hwe
    • Composites Research
    • /
    • v.20 no.5
    • /
    • pp.26-33
    • /
    • 2007
  • Pull-out and shear strengths of insert Joints of sandwich structure were investigated by experiment. Specimens were prepared by cocuring of nomex honeycomb core and carbon-epoxy composite face using an adhesive FM73. A total of 75 specimens with 10 different types depending on the core height and density, face thickness, and loading direction were tested. In the test under pull-out loading, although both the core height and density affect the failure loads, the effect of cell density is more serious. Dominant factor fur failure loads of the joints under shear loading is face thickness and the effect of core height is negligible. In the joint with same dimension, failure loads vary depending on the potted area of the core, particularly in the pull-out test.

An Experimental Study on the Failure of a Novel Composite Sandwich Structure (새로운 형상의 복합재 샌드위치 체결부 구조의 파손거동 연구)

  • Kwak, Byeong-Su;Kim, Hong-Il;Dong, Seung-Jin;Choi, Jin-Ho;Kweon, Jin-Hwe
    • Composites Research
    • /
    • v.29 no.4
    • /
    • pp.209-215
    • /
    • 2016
  • The failure of composite sandwich structures with thickness and material variation was studied. The main body of the structure is sandwich plate made of the carbon composite face and Aluminum honeycomb core. It is connected with composite laminated flange without core through transition region of tapered sandwich panel with foam core. Tension and compression tests were conducted for the total of 6 panels, 3 for each. Test results showed that the panels under compression are vulnerable to the face failure along the material discontinuity line between two different cores. However the failure load of which panel does not show such failure can carry 16% more load and fails in honeycomb core and face debonding. For the tensile load, the extensive delamination failure was observed at the corner radius which connects the panel and the flange. The average failure load for compression is about 7 times the tensile failure load. Accordingly, these sandwich structures should be applied to the components that endure the compressive loadings.

Buckling Analysis of Laminated Composite Cylindrical Shell under Combined Load State (복합하중상태에 있는 복합재료 원통형 쉘의 좌굴 거동)

  • Yeo, Kyoung-Su;Yang, Won-Ho;Cho, Myoung-Rae;Sung, Ki-Deug
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.7 no.9
    • /
    • pp.119-130
    • /
    • 1999
  • This paper deals buckling behavior of laminated composite cylindrical shells subjected to combination of axial compression and torison. Linear and nonlinear finite element analysis are carried out . the influence of load type, load ratio, fiber orientation angle, stacking sequence, and intial imperfect on buckling behavior is discussed.

  • PDF

A Study on the Mechanical Behavior of Biomimetic Fiber-Reinforced Composites under Pressure Loads (압력하중 하에서 생체모방 섬유강화 복합재의 기계적 거동 연구)

  • Lee, Jinho;Jo, Hyun-Seok;Kim, Myungsoo
    • Composites Research
    • /
    • v.32 no.1
    • /
    • pp.50-55
    • /
    • 2019
  • In this study, we investigated the effect of fiber alignment in helicoidal structure on the mechanical properties of biomimetic fiber-reinforced composites. Using finite element analysis, circular biomimetic fiber composites were designed and studied. Various amounts of pressure loads were applied to a surface of the composites, and then bending and failure behaviors of the composites were analyzed. The results showed various failure morphologies according to the orientation of the fibers, and it turned out that the fiber alignment in helicoidal structure significantly improved the bending strength of the composite under pressure loading. This was because the fiber alignment in various directions for each layer dispersed effectively the fracture energy from the external load into multiple directions.