• Steel and Composite Structures
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• v.44 no.3
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• pp.437-450
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• 2022

When the vertical load-bearing members in high-rise structures fail locally, the beam-column joints play an important role in the redistribution of the internal forces. In this paper, a static laboratory test of three full-scale flush flange beam-reinforced connections with side and cover plates (CP-FBSP connection) with double half-span steel beams and single L-shaped columns composed of concrete-filled steel tubes (L-CFST columns) was conducted. The influence of the side plate width and cover plate thickness on the progressive collapse resistance of the substructure was thoroughly analyzed. The failure mode, vertical force-displacement curves, strain variation, reaction force of the pin support and development of internal force in the section with the assumed plastic hinge were discussed. Then, through the verified finite element model, the corresponding analyses of the thickness and length of the side plates, the connecting length between the steel beam flange and cover plate, and the vertical-force eccentricity were carried out. The results show that the failure of all the specimens occurred through the cracking of the beam flange or the cover plate, and the beam chord rotations measured by the test were all greater than 0.085 rad. Increasing the length, thickness and width of the side plates slightly reduced the progressive collapse resistance of the substructures. The vertical-force eccentricity along the beam length reduced the progressive collapse resistance of the substructure. An increase in the connecting length between the beam flange and cover plate can significantly improve the progressive collapse resistance of substructures.

• Steel and Composite Structures
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• v.44 no.2
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• pp.199-210
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• 2022

This study build finite element analysis (FEA) models describing the bending events of coiled tubing (CT) at the wellhead and trips into the hole, accurately provide the state of stress and strain while the CT is in service. The bending moment and axial force history curves are used as loads and boundary conditions in the diametrical growth models to ensure consistency with the actual working conditions in field operations. The simulation diametrical growth results in this study are more accurate and reasonable. Analysis the factors influencing fatigue and diametrical growth shows that the internal pressure has a first-order influence on fatigue, followed by the radius of the guide arch, reel and the CT diameter. As the number of trip cycles increase, fatigue damage, residual stress and strain cumulatively increase, until CT failure occurs. Significant residual stresses remain in the CT cross-section, and the CT exhibits a residual curvature, the initial residual bending configuration of CT under wellbore constraints, after running into the hole, is sinusoidal. The residual stresses and residual bending configuration significantly decrease the buckling load, making the buckling and buckling release of CT in the downhole an elastic-plastic process, exacerbating the helical lockup. The conclusions drawn in this study will improve CT models and contribute to the operational and economic success of CT services.

• Tribology and Lubricants
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• v.38 no.6
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• pp.267-273
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• 2022

Surface texturing is the latest technology for processing grooves or dimples on the friction surface of a machine. When appropriately applied, it can reduce friction and significantly increase durability. Despite many studies over the past 20 years, most are isothermal (ISO) analyses in which the viscosity of the lubricant is constant. In practice, the viscosity changes significantly owing to the heat generated by the viscous shear of the lubricant and film-temperature boundary condition (FTBC). Although many thermohydrodynamic (THD) analyses have been performed on various sliding bearings, only few results for surface-textured bearings have been reported. This study investigates the effects of the FTBC and groove number on the THD lubrication characteristics of a surface-textured parallel thrust bearing with multiple rectangular grooves. The continuity, Navier-Stokes, and energy equations with temperature-viscosity-density relations are numerically analyzed using a commercial computational fluid dynamics code, FLUENT. The results show the pressure and temperature distributions, variations of load-carrying capacity (LCC), and friction force with four FTBCs. The FTBCs greatly influence the lubrication characteristics of surface-textured parallel thrust bearings. A groove number that maximizes the LCC exists, which depends on the FTBC. ISO analysis overestimates the LCC but underestimates friction reduction. Additional analysis of various temperature boundary conditions is required for practical applications.

• Tribology and Lubricants
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• v.39 no.1
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• pp.21-27
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• 2023

Surface texturing is widely applied to friction surfaces of various machine elements. Most of the theoretical studies have focused on isothermal (ISO) analyses which consider constant lubricant viscosity. However, there have been limited studies on the effect of oil temperature increase owing to viscous shear. Following the first part of the present study that investigated the effects of film-temperature boundary condition (FTBC) and groove number on the thermohydrodynamic (THD) lubrication characteristics of a surface-textured parallel thrust bearing with multiple rectangular grooves, this study focuses on the effect of groove depths. Current study numerically analyzes the continuity, Navier-Stokes, and energy equations with temperature-viscosity-density relations using a commercial computational fluid dynamics (CFD) software, FLUENT. The results of variation in temperature, velocity, and pressure distributions as well as load-carrying capacity (LCC) and friction force indicate that groove depth and FTBC significantly influence the temperature distribution and pressure generation. The LCC is maximum near the groove depth at which the vortex starts, smaller than the ISO result. For intense grooves, the LCC of THD may be larger than that from ISO. The frictional force decreases as the groove becomes deeper, and decreases more significantly in the case of THD. The study shows that groove depth significantly influences the THD lubrication characteristics of surface-textured parallel thrust bearings.

• Steel and Composite Structures
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• v.45 no.3
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• pp.409-423
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• 2022

Nowadays, there is a high demand for great structural implementation and multifunctionality with excellent mechanical properties. The porous structures reinforced by graphene platelets (GPLs) having valuable properties, such as heat resistance, lightweight, and excellent energy absorption, have been considerably used in different engineering implementations. However, stiffness of porous structures reduces significantly, due to the internal cavities, by adding GPLs into porous medium, effective mechanical properties of the porous structure considerably enhance. This paper is relating to vibration analysis of fluidconveying cantilever porous graphene platelet reinforced (GPLR) pipe with fractional viscoelastic model resting on foundations. A dynamical model of cantilever porous GPLR pipes conveying fluid and resting on a foundation is proposed, and the vibration, natural frequencies and primary resonant of such a system are explored. The pipe body is considered to be composed of GPLR viscoelastic polymeric pipe with porosity in which Halpin-Tsai scheme in conjunction with the fractional viscoelastic model is used to govern the construction relation of nanocomposite pipe. Three different porosity distributions through the pipe thickness are introduced. The harmonic concentrated force is also applied to the pipe and the excitation frequency is close to the first natural frequency. The governing equation for transverse motions of the pipe is derived by the Hamilton principle and then discretized by the Galerkin procedure. In order to obtain the frequency-response equation, the differential equation is solved with the assumption of small displacement, damping coefficient, and excitation amplitude by the multiple scale method. A parametric sensitivity analysis is carried out to reveal the influence of different parameters, such as nanocomposite pipe properties, fluid velocity and nonlinear viscoelastic foundation coefficients, on the primary resonance and linear natural frequency. Results indicate that the GPLs weight fraction porosity coefficient, fractional derivative order and the retardation time have substantial influences on the dynamic response of the system.

• Asia Marketing Journal
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• v.17 no.4
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• pp.21-42
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• 2016

Purpose: Social influence has a decisive role in shaping a person's cognition and behavior. Chinese face consciousness, including moral component, is an important part of Chinese traditional culture, which influences people to implement moral behavior. With both eye-tracking technology and traditional questionnaire, this research aims to explore people's moral psychology and the psychological processing mechanisms of Chinese face consciousness, as well as the impact of Chinese face consciousness on the preference for the ecological product. Method and Data: 75 college and MBA students' eye movement data were collected when they read different kinds of moral materials, as well as data from the subsequent questionnaires. To test the hypothesis, ANOVA analysis and Heat Map analysis were performed. Besides, the PROCESS of bootstrap was used to test mediation effect. Findings: The results reveal that: 1. Compared to the moral-situation reading, when subjects read immoral situations, they need more processing time due to the moral dissonance and cognitive load. 2. Compared to the control condition, when threatened moral self is primed, subjects prefer to choose ecological product. 3. Protective face orientation is the mediator between threatened moral self and preference to ecological product. Key Contributions: First, this study broadens the use of eye-tracking technology in marketing and demonstrates a better understanding of the relationship between morality and consumer behavior in a more scientific way. Second, this study not only distinguishes the meanings between "protective face orientation" and "acquisitive face orientation", but also innovatively validates that when moral self is threatened, consumers tend to choose ecological product as moral compensation in order to protect their face. It can shed light on the promotion of ecological product in practical applications.

• Structural Engineering and Mechanics
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• v.81 no.2
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• pp.179-194
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• 2022

The bending, buckling and free vibration responses of functionally graded material (FGM) beams are investigated semi-analytically by the scaled boundary finite element method (SBFEM) in this paper. In the concepts of the SBFEM, the dimension of computational domain can be reduced by one, therefore only the axial dimension of the beam is discretized using the higher order spectral element, which reduces the amount of calculation and greatly improves the calculation efficiency. The governing equation of FGM beams is derived in detail by the means of the principle of virtual work. Compared with the higher-order beam theory, fewer parameters and simpler control equations are used. And the governing equation is transformed into a first-order ordinary differential equation by introducing intermediate variables. Analytical solutions of the governing equation can be obtained by pade series expansion in the direction of thickness. Numerical example are compared with the numerical solutions provided by the previous researchers to verify the accuracy and applicability of the proposed method. The results show that the proposed formulations can quickly converge to the reference solutions by increasing the order of higher order spectral elements, and high accuracy can be achieved by using a small number of the elements. In addition, the influence of the structural sizes, material properties and boundary conditions on the mechanical behaviors of FG beams subjected to different load types is discussed.

• Earthquakes and Structures
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• v.22 no.5
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• pp.461-473
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• 2022

Energy-saving block and invisible multiribbed frame composite wall (EBIMFCW) is an important shear wall, which is composed of energy-saving blocks, steel bars and concrete. This paper conducted seismic performance tests on six 1/2-scale EBIMFCW specimens, analyzed their failure process under horizontal reciprocating load, and studied the effect of axial compression ratio on the wall's hysteresis curve and skeleton curve, ductility, energy dissipation capacity, stiffness degradation, bearing capacity degradation. A formula for calculating the peak bearing capacity of such walls was proposed. Results showed that the EBIMFCW had experienced a long time deformation from cracking to failure and exhibited signs of failure. The three seismic fortification lines of the energy-saving block, internal multiribbed frame, and outer multiribbed frame sequentially played important roles. With the increase in axial compression ratio, the peak bearing capacity and ductility of the wall increased, whereas the initial stiffness decreased. The change in axial compression ratio had a small effect on the energy dissipation capacity of the wall. In the early stage of loading, the influence of axial compression ratio on wall stiffness and strength degradation was unremarkable. In the later stage of loading, the stiffness and strength degradation of walls with high axial compression ratio were low. The displacement ductility coefficients of the wall under vertical pressure were more than 3.0 indicating that this wall type has good deformation ability. The limit values of elastic displacement angle under weak earthquake and elastic-plastic displacement angle under strong earthquake of the EBIMFCW were1/800 and 1/80, respectively.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.2
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• pp.141-150
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• 2009

When constructing a subsea tunnel in discontinuous rock mass, fluid flow in joints has a great influence on the behavior of the tunnel so that hydro-mechanical coupled analysis should be performed for the stability estimation. In practice, relaxed rock load is generally used for the design of tunnel concrete lining. In a continuum analysis, a method based on the distribution of local safety factor around a tunnel was proposed for the estimation of a potential relaxed zone. However, in the case of discontinuous rock mass in which joints are developed, the whole stability of tunnels depends on the behavior of the joints. In this study, therefore, a method is proposed for the estimation of a potential relaxed zone occurred by the excavation of a tunnel in discontinuous rock mass. The suggested method is validated by sensitivity analysis and the comparison with the results of continuum analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6A
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• pp.641-650
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• 2009

This paper presents new equations for member forces in concrete floating structures under wave loadings. The currently adopted design equations for wave loadings disregard the effect of mismatch between design wave length and the length of the structure. In most cases, however, additional internal forces occur due to disequilibriating buoyancy caused by the difference between design wave length and the length of the structure. In this study, new design equations considering the influence of the disequlibriating buoyancy is proposed. In addition, finite element solutions are sought to demonstrate the adequacy of the proposed design formulae in estimating the actual internal forces considering the structure as either rigid or flexible. It has been found that member forces are decreased approximately to around 55% for flexible model when compared with the rigid one.