• Steel and Composite Structures
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• v.22 no.5
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• pp.1085-1114
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• 2016

This paper investigates the transverse impact response for ultra lightweight cement composite (ULCC) filled pipe-in-pipe structures through a parametric study using both a validated finite element procedure and a validated theoretical model. The parametric study explores the effect of the impact loading conditions (including the impact velocity and the indenter shape), the geometric properties (including the pipe length and the dimensions of the three material layers) as well as the material properties (including the material properties of the steel pipes and the filler materials) on the impact response of the pipe-in-pipe composite structures. The global impact responses predicted by the FE procedure and by the theoretical model agree with each other closely. The parametric study using the theoretical approach indicates the close relationships among the global impact responses (including the maximum impact force and the maximum global displacement) in specimens with the equivalent thicknesses, proposed in the theoretical model, for the pipe-in-pipe composite structures. In the pipe-in-pipe composite structure, the inner steel pipe, together with the outer steel pipe, imposes a strong confinement on the infilled cement composite and enhances significantly the composite action, leading to improved impact resistance, small global and local deformations.

• Solar Energy
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• v.18 no.4
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• pp.101-110
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• 1998

The purpose of this research is to study the charateristics and manufacture of a composite heat pipe system with rotational and static pipe. A composite heat pipe system were tested to obtain the relationship between the expansion injector and auxiliary expansion for the motion of the working fluid by the experimental results. In addition the heat transport characteristics were found based on wall temperature of rotor, expansion injector, storage tank and vapor temperature. Water is used as working fluid of heat pipes. As the results of experiments, the composite heat pipe was operated for long times, 10 hour above with various rotational speed in performance. There were a few unexpected data by the capillary pumped loop at small working fluid, but as a whole the testing was successful.

• Steel and Composite Structures
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• v.18 no.2
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• pp.467-480
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• 2015

The steel-concrete composite decks have high fatigue durability and deformability in comparison with ordinary RC slabs. Withal, the steel-concrete composite deck is mostly heavier than the RC slabs. We have proposed herein a new type of steel-concrete composite deck which is lighter than the typical steel-concrete composite decks. This can be achieved by arranging hollow sectional members as shear connectors, namely, half-pipe or channel shear connectors. The present study aims to experimentally investigate mechanical characteristics of the half-pipe shear connectors under the direct shear force. The shear bond capacity and deformability of the half-pipe shear connectors are strongly affected by the thickness-to-diameter ratio. Additionally, the shear strengths of the hollow shear connectors (i.e. the half-pipe and the channel shear connectors) are compared. Furthermore, shear capacities of the hollow shear connectors equivalent to headed stud connectors are also discussed.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.401-409
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• 2007

Because of the various excellent characteristics of cast basalt materials. such as, anti-corrosion, anti-wearing, good hardness. high chemical stability, of which steel may not possess, the steel-basalt composite pipes are used in severe environments for compensating the defects of steel. However. without sufficient mechanical investigation prior to application. the basalt liners in steel-basalt composite pipes may be cracked and broken or the basalt liners are omitted from steel pipes in applications. In these cases, the merits of basalt materials may disappear and the basalt liners may not play their good roles as expected. Therefore, it is required that mechanical behavior of steel-basalt composite pipes and surrounding environments be fully examined before installation. The limit of bending moment with which steel-basalt composite pipe may safely endure is calculated and the limit curvature of the composite pipe in the safe range is presented in this paper. The temperature distributions and the thermal stresses are also computed and the limit difference of temperatures between inner and outer side of composite pipe is given together.

• Steel and Composite Structures
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• v.26 no.1
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• pp.55-66
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• 2018

In this paper, the response of an underground fibreglass reinforced plastic (FRP) composite pipe system subjected to realistic loading scenarios that may be experienced by an actual buried pipeline is investigated. The model replicates an arbitrary site with a length of buried pipeline, passing through a $90^{\circ}$ bend and into a valve pit. Various loading conditions, which include effects of pipe pressurization, differences in response between stainless steel and fibreglass composite pipes and severe loss of bed-soil support are studied. In addition to pipe response, the resulting soil stresses and ground settlement are also analysed. Furthermore, the locations of potential leakage and burst have also been identified by evaluating the contact pressures at the joints and by comparing stresses to the pipe hoop and axial failure strengths.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.323-330
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• 2001

The existing bonding methods of steel pipe piles into pile caps have many problems during construction or design. To overcome these, the composite bonding method of the bolting type and the welding type are proposed in this stud\ulcorner. The full scale test and the numerical analysis using finite element method were performed to verify the function of them. As results, the method of the filled with concrete in steel pipe piles head was good effective to increse strength. And the composite bonding methods are effective to protect the damage caused by earthquake than the bolted bonding method. Also, the composite bonding methods are cheaper than the existing bonding methods and a good construction as well.

• Steel and Composite Structures
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• v.46 no.4
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• pp.553-563
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• 2023

In the current research, the nonlinear free vibrations of curved pipes made of functionally graded (FG) carbon nanotube reinforced composite (CNTRC) materials are investigated. It is assumed that the FG-CNTRC curved pipe is supported on a three-parameter nonlinear elastic foundation and is subjected to a uniform temperature rise. Properties of the curved nanocomposite pipe are distributed across the radius of the pipe and are given by means of a refined rule of mixtures approach. It is also assumed that all thermomechanical properties of the nanocomposite pipe are temperature-dependent. The governing equations of the curved pipe are obtained using a higher order shear deformation theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the pipe. The von Kármán type of geometrical non-linearity is included into the formulation to consider the large deflection in the curved nanocomposite pipe. For the case of nanocomposite curved pipes which are simply supported in flexure and axially immovable, the motion equations are solved using the two-step perturbation technique. The closed-form expressions are provided to obtain the small- and large-amplitude frequencies of FG-CNTRC curved pipes rested on a nonlinear elastic foundation in thermal environment. Numerical results are given to explore the effects of CNT distribution pattern, the CNT volume fraction, thermal environment, nonlinear foundation stiffness, and geometrical parameters on the fundamental linear and nonlinear frequencies of the curved nanocomposite pipe.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.3
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• pp.50-61
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• 2015

This paper presents on the structural behavior of the the methyl methacrylate monomer (MMA) double wide flanged the glass fiber-reinforced polymer(GFRP) pipe composite structures for the manhole raise. The evaluation of structural performance on this composite structure was conducted by the axial load, fatigue load, and ultimate load test. The assessment indicates that the MMA double wide flanged GFRP pipe composite structures was confirmed safety, durability and reliability in result as expected. It was found that this composite structure was able to short working times to around 30-50% and construction costs to around 10-23% with compare other construction methods. Also, environmental pollution and civil complaints will be prevented because there will be no longer any noises, vibrations, dust, or construction wastes.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.429-432
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• 2003

MMA-modified fiberglass-reinforced plastic composite pipe was produced by using the binder of MMA-modified unsaturated polyester resin in which low viscosity MMA was added to unsaturated polyester resin. Sixteen specimens were made of polymer mortar and fiberglass-reinforced plastic by the centrifugal method. For these specimens the external strength tests were carried out by taking the core thickness consisting of polymer mortar and the fiberglass content per unit area as experimental variables to figure out the effect of variations of these variables influencing on flexural rigidity that is an important property for the composite pipe. Results of this study are believed to provide the basic data for more economical and practical design of MMA-modified fiberglass-reinforced plastic composite pipe.

• Advances in aircraft and spacecraft science
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• v.4 no.5
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• pp.515-528
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• 2017

Since composite structures are widely used in structural engineering, delamination in such structures is an important issue of research. Delamination is one of a principal cause of failure in composites. In This study the electrical potential (EP) technique is applied to detect and locate delamination in basalt fiber reinforced polymer (FRP) laminate composite pipe by using electrical capacitance sensor (ECS). The proposed EP method is able to identify and localize hidden delamination inside composite layers without overlapping with other method data accumulated to achieve an overall identification of the delamination location/size in a composite, with high accuracy, easy and low-cost. Twelve electrodes are mounted on the outer surface of the pipe. Afterwards, the delamination is introduced into between the three layers (0º/90º/0º)s laminates pipe, split into twelve scenarios. The dielectric properties change in basalt FRP pipe is measured before and after delamination occurred using arrays of electrical contacts and the variation in capacitance values, capacitance change and node potential distribution are analyzed. Using these changes in electrical potential due to delamination, a finite element simulation model for delamination location/size detection is generated by ANSYS and MATLAB, which are combined to simulate sensor characteristic. Response surfaces method (RSM) are adopted as a tool for solving inverse problems to estimate delamination location/size from the measured electrical potential changes of all segments between electrodes. The results show good convergence between the finite element model (FEM) and estimated results. Also the results indicate that the proposed method successfully assesses the delamination location/size for basalt FRP laminate composite pipes. The illustrated results are in excellent agreement with the experimental results available in the literature, thus validating the accuracy and reliability of the proposed technique.