Partial Interaction Research Articles

A linear two-dimensional mathematical model for thin two-layer plates with partial shear interaction, with a view towards application to laminated glass

This work presents a consistent derivation, from three-dimensional linear elasticity, of a two-dimensional mathematical model describing the bending and in-plane stretching behaviours, under a general system of quasi-static distributed loads and prescribed support displacements, of thin two-layer plates with partial shear interaction. This layerwise model is specifically tailored for the requirements posed by the analysis of laminated glass plates commonly used in building structures (consisting of two thin glass layers bonded together by an adhesive interlayer). Our approach, based on Podio-Guidugli’s method of internal constraints, avoids mutually contradictory assumptions (not uncommon in the literature on structural mechanics) and yields a complete two-dimensional characterisation of displacement, strain and stress fields that exactly satisfy the field equations of three-dimensional linear elasticity and the boundary conditions at the end faces. The choice of generalised variables is designed to bring to light the following fundamental conclusion and physical insight: the resulting two-dimensional boundary value problem is a combination of the equations of Kirchhoff and Mindlin plates (with specified rigidities).Two examples illustrate the application of the proposed model: (i) the cylindrical bending of plate strips and (ii) a family of problems with Navier-type analytical solution. The solutions exhibit continuity across the whole range of zero, partial and full interaction between the layers. Moreover, the Navier-type solutions are consistently in close agreement with the results of three-dimensional finite element analyses. On the contrary, analogous results previously reported in the literature exhibit considerable deviations. An explanation for these discrepancies is discussed in detail.

On buckling of layered composite heavy columns—Effect of interlayer bonding imperfection

Buckling loads of partial composite columns under distributed axial loads is investigated in this paper for the first time. The interlayer interaction corresponding to the level of interfacial bonding imperfection in the layered heavy composite columns is formulated in the model by a shear slip/stiffness modulus. Governing differential equations and boundary equations are derived and represented in a general dimensionless form. A semi-analytical solution is applied to the governing buckling equations of the presented model using power-series technique to extract critical loads of partial composite columns. Five different classical end types are considered namely clamped–clamped (C-C), clamped-pinned (C-P), clamped-sliding (C-S), clamped-free (C-F) and pinned–pinned (P-P). Also, for two extreme cases of non-composite/zero-interaction and full-composite/perfectly-bonded layered columns, exact closed-form characteristic buckling equations are introduced. A convergence study is conducted to ensure stability of the applied power-series solution. It is demonstrated that the obtained buckling loads for partial composite columns with different end conditions approach those obtained from the exact closed-from solution for the full-composite extreme case when the interfacial shear modulus approaches infinity. Effect of imperfect bonding between the column layers and slip on critical buckling loads is investigated. It is shown that a more realistic model based on the partial composite interaction hypothesis predicts critical loads that are less than those based on idealized composite columns with perfect interfacial bonding.

Predictive Modeling of Long-Term Glaucoma Progression Based on Initial Ophthalmic Data and Optic Nerve Head Characteristics.

PurposeThe purpose of this study was to develop a model, based on initial optic nerve head (ONH) characteristics, predictive of long-term rapid retinal nerve fiber layer (RNFL) thinning in patients with open-angle glaucoma (OAG).MethodsThis study evaluated 712 eyes with OAG that had been followed up for >5 years with annual evaluation of RNFL thickness. Baseline ophthalmic features were incorporated into the machine learning models for prediction of faster RNFL thinning. The model was trained and tested using a random forest (RF) method, and was interpreted using Shapley additive explanations. Factors associated with faster rate of RNFL thinning were statistically evaluated using a decision tree.ResultsThe RF model showed that greater lamina cribrosa (LC) curvature, higher intraocular pressure (IOP), visual field mean deviation converging towards −5 dB, and thinner peripapillary choroid at baseline were the four most significant features predicting faster RNFL thinning. Partial interaction between the features showed that larger LC curvature was a strong factor for faster RNFL thinning when it exceeded approximately 12.0. When the LC curvature was ≤12, higher initial IOP and thinner peripapillary choroid played a role in the rapid RNFL thinning. Based on the decision tree, higher IOP (>26.5 mm Hg), greater laminar curvature (>13.95), and thinner peripapillary choroid (≤117.5 µm) were the 3 most important determinants affecting the rate of RNFL thinning.ConclusionsBaseline ophthalmic data and ONH characteristics of patients with OAG were predictive of eyes at risk of faster progression. Combinations of important characteristics, such as IOP, LC curvature, and choroidal thickness, could stratify eyes into groups with different rates of RNFL thinning.Translational Relevance This work lays the foundations for developing prediction models to estimate glaucoma prognosis based on initial ONH characteristics.

A New Bond-Slip Model of Hybrid Bonded FRP-to-Concrete Joints

The dowel effect in hybrid bonded fiber reinforced plastic (HB-FRP) to concrete joints is difficult to quantify and make the anchoring joint instability. A new HB-FRP joint was built, which eliminates bonding between steel and FRP plates. Based on an empirical model of external bonding FRP (EB-FRP) to concrete joints and the new model of slip at debonding, the new unified bond-slip model of the HB-FRP joints is proposed. The parameters that affect the bond-slip model are analyzed. Pull-off tests are conducted for eight specimens with different numbers of mechanical fasteners, which has verified the proposed model. The load-slip relationship at the loaded end of the FRP plate was well predicted by the partial interaction numerical calculation and further verify the theoretical model.

Theoretical and numerical bonding capacity model of FRP-to-concrete joints with mechanical fastening

The coordination of multiple anchors can improve the interfacial bonding capacity of hybird bonded fibre reinforced plastic (HB-FRP) joints to concrete. But the discontinuity of the bond stress at the anchor makes it difficult to predict the bonding capacity. To solve this problem, in this study, the bonding behaviour for one anchor is derived based on the bilinear model and the threefold bond-slip model of the EB-FRP (external bonding FRP) joint and the HB-FRP joint, respectively, by using the same slip at the boundary of adjacent bonding zones. The bonding capacity of HB-FRP joints with multiple anchors is predicted. A numerical method based on the partial interaction model is proposed to predict the development of interfacial stress. The theoretical and numerical methods are mutually verified with experimental results. Finally, the influence of the bond-slip model on the bonding characteristics of the HB-FRP joints is analyzed.

Bond-slip behavior of steel reinforced UHPC under flexure: Experiment and prediction

Ultra-high performance concrete (UHPC) is an advanced class of concrete materials that show superior mechanical and durability performance. While several studies have investigated the bond-slip behavior of steel reinforced UHPC using pullout tests, very limited information is available on the bond-slip behavior of reinforced UHPC from beam-type tests, which produce flexural stress states commonly seen in structural members. This study experimentally examines the local bond-slip behavior of reinforced UHPC using beam-end tests. The test variables include UHPC material designs (one low-cement, green UHPC mix and one typical UHPC mix), fiber volumes (0%, 0.5%, and 1.0%), cover thickness (16 mm–51 mm), steel bar sizes (16 mm–32 mm), and test ages (3 days and 50 days). A total of thirty-two tests are conducted. While the non-fiber UHPC specimens fail in a brittle manner due to splitting failure, all fiber-reinforced UHPC specimens exhibit confined splitting failure and ductile bond-slip responses. The peak bond strength is found to exhibit a linear relationship with the cover-thickness-to-bar-diameter ratio and the square root of UHPC compressive strength. Furthermore, a local bond-slip model is developed, which includes a new bond-strength prediction method that predicts the experimental results with a mean absolute error of 7.6%. Finally, this local bond-slip model is combined with a partial interaction model to explore the global bond stress variations under different embedment lengths and flexural states. Equations are proposed to predict the development length that can lead to reinforcement yielding with minimized bonded length or minimized global slip.

Research on Bending Performance of Concrete Sandwich Laminated Floor Slabs with Integrated Thermal and Sound Insulation

In this study, a full-scale test on the bending performance of concrete sandwich laminated floor slabs with integrated thermal and sound insulation was carried out, and the effects of different reinforcement ratios on the bending performance of concrete sandwich laminated floor slabs were investigated as well as the variation law of the failure modes, characteristic loads, load-mid span deflection, load-rebar strain curves, and anti-slip performance. The results indicate that the concrete sandwich laminated floor slabs present typical bending failure characteristics. According to bending failure characteristics, the damage process can be divided into three stages, i.e., elasticity, cracking, and failure. The bearing capacity significantly increases with the increase in reinforcement ratio. The normal service, yield, and ultimate loads of bearing capacity of the floor slabs with a larger reinforcement ratio increase by 54.55%, 52.94%, and 46.46%, respectively. Moreover, the mid-span deflection decreases significantly with the increase in reinforcement ratio, and the cracking expansion is also delayed. Before cracking, the prefabricated layer and laminated layer can realize load bearing together, and the floor slab is in a state of complete interaction. When the floor slabs reach the ultimate state, the superimposed surface produces a sliding effect, and the floor slab is in a state of partial interaction. The finite element analysis software ABAQUS (with the version number of ABAQUS 2020, the chief creator of David Hibbitt, and the sourced location of the United States) was used to perform nonlinear numerical simulation. The test results accord well with the simulation results, which verifies the correctness of the finite element model. Based on finite element simulation, the influence of post-cast concrete strength on the ultimate load can be ignored.

Synergetic enhancement of activity and selectivity for reverse water gas shift reaction on Pt-Re/SiO2 catalysts

Catalytic reduction of CO2 with renewable H2 to CO via the reverse water gas shift (RWGS) reaction is an attractive approach to recycle CO2 and control net emission of CO2 to atmosphere. However, low activity and high CH4 selectivity at low temperatures limited the practical implementation of the reaction. Herein, Pt-Re/SiO2 catalysts with varying amount of Re were prepared with co-impregnation and tested for the RWGS reaction. Characterization results indicated that the oxophilic ReOx (0 ≤ x ≤ 3.5) located in close proximity to Pt particle, modified the surface of Pt by both partial coverage and electronic interaction, resulting in the reduced number of sites for and weakened strength of CO adsorption. At 400 °C, the turnover frequency (2.30 s−1) on the optimal Pt-Re/SiO2 catalyst (Pt/Re = 1.91) is 3.9 times higher than that on Pt/SiO2 under differential conditions, and the apparent activation energy is lowered. In contrast to Re/SiO2 which produces significant amount of CH4, the CO selectivity on Pt-Re/SiO2 maintained > 96.2 % under integral conditions. Reaction order analysis revealed that Pt facilitates H2 activation whereas the oxophilic ReOx enhances CO2 adsorption and activation. The perimeter sites at the Pt/ReOx interface with a balanced hydrogenation and C-O cleavage properties synergistically improve the RWGS activity while inhibiting CH4 production.

Photon interaction of molybdenum (Mo) based cesium tri-molybdate (Cs2Mo3O10) and disodium dimolybdate (Na2Mo2O7) single crystal scintillators

Both single crystals, molybdenum-based cesium tri-molybdate and disodium dimolybdate single crystal scintillators were investigated for gamma-rays interaction. The theoretical mass attenuation coefficients have been calculated by the WinXCom program. The 137Cs source was used in the experiment that was irradiated with eight different photon energies using the Compton scattering technique. The theoretical result shows that the mass attenuation coefficient of both scintillators depends on photon energy and decreases with increasing of photon energy. The molybdenum-based cesium tri-molybdate shows higher values of the mass attenuation coefficient than disodium dimolybdate scintillator all the energy range. The experimental result shows the same trend and are good agreement with theoretical. The values of molybdenum-based cesium tri-molybdate show decreased from 22.15 to 7.7 ( × 10−2 cm2/g) and the disodium dimolybdate scintillator shows decreased from 16.05 to 7.4 ( × 10−2 cm2/g). Moreover, the partial interaction, the effective atomic number, and the effective electron density were also investigated.

Analytical Study on Time-Dependent Stiffness of Stud Shear Connectors

Concrete creep weakens the spring stiffness of stud shear connectors (SSCs) and increases the long-term deflection of long-span composite beams. The time-dependent properties of SSC are of great importance for the long-term evaluation of composite steel construction. This paper proposes the time-dependent stiffness (TDS) method based on the analytical solution of the beam on a viscoelastic foundation to simulate the SSC under the sustained push-out load. TDS method combines beam theory and the viscoelastic property of hardened concrete. The long-term slip of SSC is predicted by hand calculation of the explicitly expressed governing equation, and it is close to the refined finite element analysis (FEA) results. The constants and parameters used to determine TDS seem to be insensitive regarding geometric and material variation. TDS may provide a simplified method to incorporate the time-dependent partial interaction into complex composite structures by saving the consumption of computer storage and advanced modeling time which are usually required in the refined modeling at the steel-concrete interface, especially when the long-term properties of concrete are of interest.

Flow-induced coupled vibrations of an elastically mounted cylinder and a detached flexible plate

A fluid multi-structure interaction (FMSI) study on flow-induced coupled vibrations of an elastically mounted cylinder and a detached flexible plate is carried out numerically at a constant $Re=100$ . The effect of a non-dimensional gap $G^{*}$ between the two structures, and reduced velocity $U_{c}^{*}$ , on the proximity-induced coupled flow physics and vibration characteristics of the system is presented. The FMSI system shows a two-state response: state 1 at larger gaps $G^{*}\geqslant 1$ , and state 2 at smaller gaps $G^{*}\leqslant 0.5$ . At larger $U_{c}^{*}$ , the plate encounters an oscillating wake flow in state 1, while it encounters onset of gap flow in state 2. Each state relates to distinct vibration characteristics of both the structures, with the cylinder showing a vortex-induced vibration response in state 1 and a galloping response in state 2. The amplitude response of the cylinder is governed by gap flow dynamics while that of the plate is governed by the cylinder–plate vortex-interaction dynamics. In addition to the constructive and destructive vortex interactions reported earlier, a partial vortex interaction is observed here. The vortex interactions in the near wake lead to distinct vortex-shedding patterns – 2S, C(2S), 2P and a novel C(2P) – in the far wake. Separate regime maps are presented for the various types of cylinder–plate vortex interactions and vortex-shedding patterns, correlated with the amplitude, frequency and phase difference of the coupled vibrations of the cylinder and plate. The vortex dynamics shows a strong correlation with the quantitative vibration parameters, indicating the strongly coupled multi-physics characteristics of the present FMSI system.

Finite-Time Consensus Tracking Control for Speed Sensorless Multi-Motor Systems

Considering the unknown compound interference in manufacturing systems, the finite-time tracking and synchronization performance of the multi-motor system significantly affects the production safety, reliability, and quality, which can be considered a multi-agent system with unmeasured speed and uncertainty. In recent years, the synchronous control schemes of the multi-motor system have grown to maturity, but the research on the speed sensorless finite-time consensus tracking control remains to be extended. This paper proposes an observer-based leader–follower consensus tracking control for the synchronous coordination control of the multi-motor system. The speed and position of all motors can be tracked by consensus in a finite time when only some motors realize partial interaction. First, a finite-time observer is designed to estimate the unknown composite disturbance and unmeasurable speed variable of each motor. Second, the distributed finite-time consensus tracking control protocol is designed using the observed value and local information interaction. The stability of the overall closed-loop system is theoretically analyzed based on Lyapunov theory and graph theory, which shows that the consensus tracking error converges to an arbitrary small neighborhood of zero, and all signals are globally bounded in finite time. Finally, simulation results are provided to illustrate the effectiveness of the proposed control method.

Harnessing Greenhouse Gases Absorption by Doped Fullerenes with Externally Oriented Electric Field.

In this work, a theoretical investigation of the effects caused by the doping of C20 with silicon (Si) atom as well as the adsorption of CO, CO2 and N2 gases to C20 and C19Si fullerenes was carried out. In concordance with previous studies, it was found that the choice of the doping site can control the structural, electronic, and energetic characteristics of the C19Si system. The ability of C20 and C19Si to adsorb CO, CO2 and N2 gas molecules was evaluated. In order to modulate the process of adsorption of these chemical species to C19Si, an externally oriented electric field was included in the theoretical calculations. It was observed that C19Si is highly selective with respect to CO adsorption. Upon the increase of the electric field intensity the adsorption energy was magnified correspondingly and that the interaction between CO and C19Si changes in nature from a physical adsorption to a partial covalent character interaction.

Two-dimensional elasticity model for composite beams with deformable shear connectors: Analytical and numerical solutions

A novel and efficient exact two-dimensional (2D) model is developed for predicting the flexural response of two-layered composite beams made of different materials based on the elasticity theory. The beam is considered as a specific case of plane stress problem laying in the longitudinal vertical plane passing through the centroid of the beam section. The proposed two-dimensional model considers the orthotropic properties of materials used in composite beams. The partial shear interaction between two material layers in the form of shear slip at their interface is also considered in this study. The deformable shear connectors between these layers are modeled using distributed shear springs along the beam length. The present 2D model's accuracy is validated by comparing its results with published results as well as numerical results generated by a thorough 2D finite element model using ABAQUS. Furthermore, the stretching effect over the direction of beam depth on the flexural response of two-layered composite beams is investigated by comparing the results produced by the one-dimensional (1D) HBT model and the proposed 2D elasticity model.

How does sovereign bond volatility interact between African countries?

The importance of sovereign bond as a source of financing revenue deficit, benchmarking for corporate bonds and debt management in Africa, calls for continual monitoring of its volatility dynamics. This study evaluates the nature of sovereign bond volatility interaction between African countries using bivariate BEKK-GARCH (1, 1) model. Based on a sample of eight African countries, the results show evidence of unidirectional volatility spillover from Morocco sovereign bond to Egypt sovereign bond. Next, the results show absence of volatility interaction between Ghana and Nigeria sovereign bonds. The results further show the existence of bidirectional volatility transmission between Uganda and Kenya. Finally, the results indicate evidence of bidirectional volatility interaction between Botswana and South Africa. Overall, the results show existence of full interaction between Uganda–Kenya and Botswana–South Africa sovereign bond returns, partial interaction between Egypt and Morocco sovereign bond returns and no interaction between Ghana and Nigeria sovereign bonds markets. Thus, these results provide valuable implications for sovereign and corporate credit risk management, as well as strategy for monitoring and minimising negative effect of sovereign bond volatility spillover in Africa.

An analytical model for flexural vibration of composite beams with shear slip based on third order deformation kinematics

In this paper, an analytical solution is derived for accurately predicting the free and forced vibration responses due to time varying as well as moving loads of two layered composite beams which consist of two different materials. For this purpose, the third order deformation kinematics is used in the proposed model, and it allows to take a parabolic (third order) variation of the longitudinal displacement along the beam depth for the two material layers. The partial shear interaction between the two material layers produced by the deformability of shear connectors joining these layers in the form of shear slip at their interface is modelled using distributed shear springs along the beam length. Hamilton’s principle is applied to derive the governing equations of the dynamic system which are solved analytically using a Navier type solution technique. Moreover, a two-dimensional (2D) finite element model is built up in ABAQUS for the validation of the proposed analytical model. Some parametric studies are conducted to investigate the effect of shear deformation on the forced vibration response of a two-layered composite beam partial with different shear stiffness, span-to-depth ratio and elastic-to-shear modulus ratio.

An innovated theory and closed form solutions for the elastic lateral torsional buckling analysis of steel beams/columns strengthened with symmetrically balanced GFRP laminates

An innovated theory based on the principle of total stationary buckling energy is successfully developed for the elastic lateral torsional buckling analysis of steel beams/columns strengthened with symmetrically balanced GFRP laminates. Two closed form solutions and four eigenvalue solutions of the buckling resistances are then developed based on the theory and based on postulated buckling displacement functions. The present theory captures the partial interaction between the steel member and the GFRP laminates, stacking sequences and orthotropic properties of GFRP laminae, shear deformations in the GFRP laminates, and local and global warping deformations. The elastic buckling resistances predicted by the present solutions are well validated against those of three dimensional finite element analyses, as presented in three examples and two parametric studies of the present study. The present solutions are fast and convenient to predict the elastic buckling resistances of GFRP-strengthened beams/columns. Based on the parametric studies conducted, it is observed that the effects of GFRP lamina stacking sequences (with different fiber orientation angles), GFRP laminate thicknesses, GFRP moduli of elasticity, GFRP shear moduli, and adhesive shear moduli on the elastic buckling resistances are significant.

팀 정체성의 강도 및 멀티 페르소나의 역학관계가 스포츠팬들의 삶의 만족에 미치는 영향

The purpose of this study was to examine the effects of the strength of team identification and the dynamics of multi-persona and their interaction effects on sport fans’ life satisfaction. For this purpose, a 2(team identification: high vs. low) × 2(multi-persona: similar vs. different) factorial design was utilized with scenarios that represent 4 experimental conditions. A two-way ANOVA and a simple effect test(n=480) were conducted to test the direct and indirect effects of these two independent variables on life satisfaction. The results of this study are as follows. First, the strength of team identification had a positive effect on life satisfaction. Second, the dynamics of multi-persona did not have any effect on life satisfaction. Third, there was the effect of partial interaction between the two independent variables on life satisfaction. Specifically, the difference-based multi-persona was more effective in life satisfaction for highly identified fans. These findings provide sport marketers with insight into how they develop marketing strategies for enhancing sport fans’ life satisfaction that are grounded in team identification itself and team identification in combination with multi-persona.

Comparison of the Influence of Good Corporate Governance, Return on Asset, Net Profit Margin on Company Value with Corporate Social Responsibility as Moderating Variables (Empirical Study on Banking and Mining Companies Listed on the Indonesia Stock Exchange 2016-2020)

The purpose of this study was to analyze the comparison of the influence of Good Corporate Governance, Return on Asset, Net Profit Margin on corporate value with Corporate Social Responsibility as a moderation variable of empirical studies on banking and mining companies listed on the Indonesia Stock Exchange. The study used 26 banking companies and 15 mining companies listed on the Indonesia Stock Exchange selected using the Purposive Sampling method in the period 2016-2020. This research data was analyzed using multiple regression analysis methods. The results showed that simultaneously the influence of variables Good Corporate Governance, Return On Asset, Net Profit Margin, and Corporate Social Responsibility positively affect the value of banking and mining companies. Return on Asset partially has no significant effect on the value of banking companies, while Return On Asset partially has a significant positive effect on the value of mining companies. Net Profit Margin partially had no significant effect on the value of banking and mining companies. The study also found that partial interaction of Corporate Social Responsibility variables proved to significantly moderate the relationship of the influence of Good Corporate Governance, Return On Asset, Net Profit Margin on the value of banking and mining companies.

Mathematical calculation of gamma rays interaction in bismuth gadolinium silicate glass using WinXCom program

The WO3 doped bismuth gadolinium silicate glass have been calculated using WinXCom program at the gamma energy range of 1 keV to 100 GeV in the concentration of WO3 = 0, 10, 20 and 30 mol%. The mass attenuation coefficient, the partial interaction and effective atomic number were investigated. The results of the photoelectric absorption, the μm and the Zeff show the similar trend and the absorption edges were observed at an energy lower than 100 keV. The result can be found the photoelectric absorption at low photon energy, the Compton scattering in the medium photon energy and the pair production effect has the main interaction at high photon energy. Furthermore, the Zeff show increasing the concentration of WO3 the values because of the atomic number of W replacing Si in the glass matrix.