• 한국전기화학회:학술대회논문집
• /
• 한국전기화학회 2000년도 춘계총회 및 학술발표회
• /
• pp.25-25
• /
• 2000

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2002년도 추계학술발표강연 및 논문개요집
• /
• pp.36-36
• /
• 2002

• Steel and Composite Structures
• /
• 제10권1호
• /
• pp.23-43
• /
• 2010

In this paper, a nonlinear model is developed using the component method in order to represent the response of steel connections under various loading conditions and temperature variations. The model is capable of depicting the behaviour of a number of typical connection types including endplate forms (extended and flush) and angle configurations (double web, top and seat, and combined top-seat-web) in both steel and composite framed structures. The implementation is undertaken within the finite element program ADAPTIC, which accounts for material and geometric nonlinearities. Verification of the proposed connection model is carried out by comparing analytical simulations with available results of isolated joint tests for the ambient case, and isolated joint as well as sub-frame tests for elevated temperature conditions. The findings illustrate the reliability and efficiency of the proposed model in capturing the stiffness and strength properties of connections, hence highlighting the adequacy of the component approach in simulating the overall joint behaviour at elevated temperature.

• The Korean Journal of Ceramics
• /
• 제5권2호
• /
• pp.155-161
• /
• 1999

The tribological behaviour of monolithic SiC as well as SiC-TiC and SiC-TiC-$TiB_2$ particulate composite materials has been investigated in unlubricated oscillating sliding tests against $Al_2O_3$ at temperature in the range from room temperature up to $600^{\circ}C$. At temperatures below $600^{\circ}C$ the wear rate of the systems with the composite materials was up to 20 times lower than the wear of the $Al_2O_3$/SiC system and was dominated by the oxidation of the titanium phases. At $600^{\circ}C$ the oxidation rate of the TiC and -TEX>$TiB_2$ grains becomes predominant resulting in an enhanced wear rate of the composite rate of the TiC and TiB2 grains becomes predominant resulting in an enhanced wear rate of the composite materials. The coefficient of friction shows similar values for all materials of investigation, increasing from 0.25…0.3 at room temperature to 0.7…0.8 $600^{\circ}C$. The wear of the $Al_2O_3$/SiC system is mainly abrasive at temperatures above room temperature and is characterised by an enhanced wear of the alumina ball at $600^{\circ}C$.

• Steel and Composite Structures
• /
• 제19권4호
• /
• pp.1011-1033
• /
• 2015

In this article, large amplitude bending behaviour of laminated composite flat panel under combined effect of moisture, temperature and mechanical loading is investigated. The laminated composite panel model has been developed mathematically by introducing the geometrical nonlinearity in Green-Lagrange sense in the framework of higher-order shear deformation theory. The present study includes the degraded composite material properties at elevated temperature and moisture concentration. In order to achieve any general case, all the nonlinear higher order terms have been included in the present formulation and the material property variations are introduced through the micromechanical model. The nonlinear governing equation is obtained using the variational principle and discretised using finite element steps. The convergence behaviour of the present numerical model has been checked. The present proposed model has been validated by comparing the responses with those available published results. Some new numerical examples have been solved to show the effect of various parameters on the bending behaviour of laminated composite flat panel under hygro-thermo-mechanical loading.

• Steel and Composite Structures
• /
• 제8권3호
• /
• pp.243-264
• /
• 2008

This paper details a testing facility ("NATURAL FIRE FACILITY") that allows closely-controlled experimental testing on full-scale sub-frames while reproducing the spatially transient temperature conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span, supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.

• 국제초고층학회논문집
• /
• 제7권4호
• /
• pp.327-342
• /
• 2018

Geopolymer concrete (GPC), which is recognised as an environmentally friendly alternative to ordinary Portland cement (OPC) concrete, has been reported to possess high fire resistance. However, very limited research has been conducted to investigate the behaviour of geopolymer concrete-filled steel tubular (GCFST) columns at either ambient or elevated temperatures. This paper presents the compressive test results of a total of 15 circular concrete-filled steel tubular (CFST) stub columns, including 5 specimens tested at room temperature, 5 specimens tested at elevated temperatures and the remaining 5 specimens tested for residual strength after exposure to elevated temperatures. The main variables in the test program include: (a) concrete type; (b) concrete strength; and (c) curing condition of geopolymer concrete. The test results demonstrate that GCFST columns have similar ambient temperature behaviour compared with the conventional CFST counterparts. However, GCFST columns exhibit better fire resistance than the conventional CFST columns. Meanwhile, it is found that the GCFST column made with heat cured GPC has lower strength loss than other columns after exposure to elevated temperatures. The research results highlight the possibility of using geopolymer concrete to improve the fire resistance of CFST columns.

• 국제초고층학회논문집
• /
• 제7권4호
• /
• pp.343-362
• /
• 2018

A simplified spring connection modelling approach for steel flush endplate beam-to-column connections in fire has been developed to enable realistic behaviour of connections to be incorporated into full-scale frame analyses at elevated temperature. Due to its simplicity and reliability, the proposed approach permits full-scale high-temperature frame analysis to be conducted without high computational cost. The proposed simplified spring connection modelling approach has been used to investigate the influence of connection ductility (both axial and rotational) on frame behaviour in fire. 2D steel and 3D composite frames with a range of beam spans were modelled to aid the understanding of the differences in frame response in fire where the beam-to-column connections have different axial and rotational ductility assumptions. The modelling results highlight that adopting the conventional rigid or pinned connection assumptions does not permit the axial forces acting on the connections to be accurately predicted, since the axial ductility of the connection is completely neglected when the rotational ductility is either fully restrained or free. By accounting for realistic axial and rotational ductilities of beam-to-column connections, the frame response in fire can be predicted more accurately, which is advantageous in performance-based structural fire engineering design.

• Tribology and Lubricants
• /
• 제5권2호
• /
• pp.42-47
• /
• 1989

The thermal behaviour of layerd solids, typified in practice by surface coated materials, is evaluated for the specific case of a fast moving heat source. This is intended to represent the particular instance of solids in sliding contact and the consequences of friction. The finite difference method has been utilised to establish the temperature distributions at the surface and also the sub-surface region for coating materials which are either less conductive or more conductive than the substrate to which they are attached. The effects of variation in layer thickness, and also the load, speed and friction coefficient, are evaluated.

• Steel and Composite Structures
• /
• 제17권1호
• /
• pp.47-67
• /
• 2014

Due to thermal expansion, the structural behaviour of beams in steel structures subjected to temperature increase will be affected. This may result in the failure of the structural members or connection due to extra internal force in the beam induced by the thermal increase. A method to release some of the thermally generated internal force in the members is to allow for some movements at the end supports of the member. This can be achieved by making the plane of the end-plate of the connection slanted instead of vertical as in conventional design. The present paper discusses the mechanical behaviour of beams with bolted slant end-plate connection under symmetrical gravity loads, subjected to temperature increase. Analyses have been carried out to investigate the reduction in internal force with various angles of slanting, friction factor at the surface of the connection, and allowable temperature increase in the beam. The main conclusion is that higher thermal increase is tolerable when slanting connection is used, which means the risk of failure of structures can be reduced.