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1 – 10 of over 59000Yuxuan Wu, Wenyuan Xu, Tianlai Yu and Yifan Wang
Polyurethane concrete (PUC), as a new type of steel bridge deck paving material, the bond-slip pattern at the interface with the steel plate is not yet clear. In this study, the…
Abstract
Purpose
Polyurethane concrete (PUC), as a new type of steel bridge deck paving material, the bond-slip pattern at the interface with the steel plate is not yet clear. In this study, the mechanical properties of the PUC and steel plate interface under the coupled action of temperature, normal force and tangential force were explored through shear tests and numerical simulations. An analytical model for bond-slip at the PUC/steel plate interface and a predictive model for the shear strength of the PUC/steel plate interface were developed.
Design/methodology/approach
The new shear test device designed in this paper overcomes the defect that the traditional oblique shear test cannot test the interface shear performance under the condition of fixed normal force. The universal testing machine (UTM) test machine was used to adjust the test temperature conditions. Combined with the results of the bond-slip test, the finite element simulation of the interface is completed by using the COHENSIVE unit to analyze the local stress distribution characteristics of the interface. The use of variance-based uncertainty analysis guaranteed the validity of the simulation.
Findings
The shear strength (τf) at the PUC-plate interface was negatively correlated with temperature while it was positively correlated with normal stress. The effect of temperature on the shear properties was more significant than that of normal stress. The slip corresponding to the maximum shear (D1) positively correlates with both temperature and normal stress. The interfacial shear ductility improves with increasing temperature.
Originality/value
Based on the PUC bond-slip measured curves, the relationship between bond stress and slip at different stages was analyzed, and the bond-slip analytical model at different stages was established; the model was defined by key parameters such as elastic ultimate shear stress τ0, peak stress τf and interface fracture energy Gf.
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It is well known that stress singularity may exist at the edges of a bonded bi‐material interface due to the discontinuity of material properties. This stress singularity causes…
Abstract
Purpose
It is well known that stress singularity may exist at the edges of a bonded bi‐material interface due to the discontinuity of material properties. This stress singularity causes difficulty in accurately determining the bi‐material interface bonding strength. This paper aims to present a new design of specimen geometry to eliminate the stress singularity and present an experimental procedure to more accurately determine the bonding strength of the bi‐material interface.
Design/methodology/approach
The design is based on an asymptotic analysis of the stress field near the free edge of bi‐material interface. The critical bonding angle, which delineates the singular and non‐singular stress field near the free edge, is determined.
Findings
With the new designed specimen and a special iterative calculation algorithm, the interface bonding strength envelope of an epoxy‐aluminum interface was experimentally determined.
Originality/value
This new design of specimen, experimental procedure and iterative algorithm may be applied to obtain more reasonable and accurate bonding strength data for a wide range of bi‐material interfaces.
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Liang Lu and Wenhu Huang
As the installation of the vibration isolation device to the spacecraft for the whole spacecraft vibration isolation, the interface structure is typically modeled as a rigid…
Abstract
Purpose
As the installation of the vibration isolation device to the spacecraft for the whole spacecraft vibration isolation, the interface structure is typically modeled as a rigid structure during the design phase. However, the flexibility of the interface structure does exist for a large‐sized adaptor. This is a source of uncertainty and could reduce the reliability of the system. It is necessary to investigate the influence of this type of flexibility on the vibration isolation performance in an engineering practice. This paper aims to address this situation.
Design/methodology/approach
The vibratory transmissibility from the bottom of the isolator is generally used to evaluate the performance of the vibration isolation. By introducing the interface flexibility from both the adaptor and the vibration isolation device, a planar model which includes a flexible beam representing the interface structure is established to study the influence of this type of flexibility on the vibratory transmissibility.
Findings
It is found that, when this type of flexibility is included, an extra low‐frequency mode dominated locally by the interface structure is induced, and then a significant resonance appears in the vibratory transmissibility of the vibration isolation device at a low frequency.
Originality/value
The vibration isolation performance may be over‐estimated in the design by taking the interface as rigid. The inherent flexibility of the interface structure, on the other hand, may degrade the performance of the vibration isolation device and degrade the function of the rotation constraint device added into the vibration isolation device.
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Ningbo Liao and Ping Yang
The small dimensions of future device designs also imply a stronger effect of material boundary resistance. For nanoscale devices and structures, especially, interface phenomena…
Abstract
Purpose
The small dimensions of future device designs also imply a stronger effect of material boundary resistance. For nanoscale devices and structures, especially, interface phenomena often dominate their overall thermal behavior. The purpose of this paper is to propose molecular dynamics (MD) simulations to investigate the mechanical and thermal properties at Cu‐Al interface.
Design/methodology/approach
The two‐temperature model (TTM)‐MD model is used to describe the electron‐phonon scattering at interface of different metals. Before the simulation of heat transfer process, a non‐ideal Cu‐Al interface is constructed by simulating diffusion bonding.
Findings
According to the simulation results, in unsteady state, the temperature distribution and the displacements of atoms near the interface tend to generate stress and voids. It reveals the damage mechanics at the interface in heat transfer.
Originality/value
The atomic model proposed in this paper is computationally efficient for interfacial heat transfer problems, and could be used for investigation of other interfacial behaviors of dissimilar materials.
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Looks at the design elements of an effective human interface. Outlineswhat makes a good interface and why so many are bad. Explains the importanceof having a clear idea of what…
Abstract
Looks at the design elements of an effective human interface. Outlines what makes a good interface and why so many are bad. Explains the importance of having a clear idea of what jobs are to be done and an understanding of the ways errors happen. Also explains the need to understand and involve the user and the importance of trying out the interface at an early stage. Concludes that bad interfaces cost money and can be dangerous and that the human interface should attract at least the same level of resources as any other major part of system design.
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Hartmut Brauer, Marek Ziolkowski and Milko Kuilekov
The interface between two conducting fluids in a magnetic fluid dynamics (MFD) problem was identified by means of external magnetic field measurements. Genetic algorithms (GA…
Abstract
Purpose
The interface between two conducting fluids in a magnetic fluid dynamics (MFD) problem was identified by means of external magnetic field measurements. Genetic algorithms (GA) were applied to solve the inverse problem.The principal component analysis (PCA) was used to speed up the process of interface reconstruction.
Design/methodology/approach
With respect to the experimental results we have designed a general technique for mode identification and/or interface reconstruction. Two main procedures are available to solve the inverse problem, the full interface reconstruction and the principle component analysis (PCA) mode. In the case of full reconstruction, it can be decided whether an algorithm for fast identification of the dominant modes applying a FFT module should be performed or not. The full interface reconstruction applies stochastic optimization methods ((GA) or evolution strategies (ES)) for the estimation of the interface shape characteristics. The main goal of the PCA mode is to find the dominant mode of the interface shape and its amplitude. The PCA mode is realized by means of stochastic optimization methods (GA, ES) and a simple direct searching (DS) using the golden section technique.
Findings
PCA with GA procedure enables the identification of the dominant mode of the interface shape between two conducting fluids with sufficient accuracy for simulated magnetic fields. Time of identification is strongly reduced due to a redefinition of the genotype representations in the PCA mode. Accuracy of reconstruction depends on the noise level, i.e. signal to noise ratio and a geometrical model used in the reconstruction phase. The correlation between the noise level and values of cost function for identified modes has been found if a proper geometry modelling is applied.
Originality/value
The paper describes a new, fast technique for solving an inverse field problem of a MFD problem where the interface between two conducting fluids has to be identified using a magnetic field tomography measuring system.
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Mansor Yushiana and Widyawati Abdul Rani
The purpose of this paper is to investigate the usability of a web‐based OPAC (WebPAC) user interface at the International Islamic University Malaysia (IIUM). It also looks at the…
Abstract
Purpose
The purpose of this paper is to investigate the usability of a web‐based OPAC (WebPAC) user interface at the International Islamic University Malaysia (IIUM). It also looks at the applicability of heuristic evaluation in designing a user‐centered WebPAC interface.
Design/methodology/approach
Based on Nielsen's ten usability heuristic principles, the study focuses on three heuristics only, i.e. aesthetic and minimalist design, match between interface and the real world, and visibility of interface status.
Findings
Results of the study found that the WebPAC interface conforms to at least 70 percent usability properties prescribed. Usability problems violated in the interface were identified.
Practical implications
The study suggests that heuristic evaluation is applicable in libraries to asses the usability of user interface for online catalogs.
Originality/value
Heuristic evaluation could assist libraries in designing user‐centered interface for online catalogs.
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Abstract
Purpose
In recent years, using aberration-corrected transmission electron microscopy, the authors have achieved precisely detecting the structural evolution of passive film as well as its interface zone at atomic scale. The purpose of this paper aims to make a brief review to show the authors’ new understanding and perspective on the issue of critical factors determining stability of passive film of Fe-Cr alloy.
Design/methodology/approach
The introduction of single crystal enabled the authors to obtain a distinct metal/passive film interface and better characterize the structure of the interface region. The authors use aberration-corrected TEM to conduct cross-sectional observation and directly capture the details across the entire film at a high spatial and energy resolution.
Findings
Apart from the passive film itself, the interface zone, including metal/film (Me/F) interface and the adjacent metal side, is also the site which is attacked. Accordingly, the nature of the interface zone, such as microstructure, composition and atomic configuration, is one of the critical factors determining the stability of passive film.
Originality/value
Deciphering the critical factors determining the stability of passive film is of great significance and has been a fundamental issue in corrosion science. Great attention has been paid to the nature of the passive film itself. In contrast, the possible role of the interface between the passive film and the metal is rarely taken into account. Based on the advanced analytical tool with high spatial resolution, the authors have specified the significant role of interface structures on the macro-scale stability of passive film.
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Amrit Raj Paul, Manidipto Mukherjee and Mohit Kumar Sahu
The purpose of this study is to investigate the deposition of SS–Al transitional wall using the wire arc directed energy deposition (WA-DED) process with a Cu interlayer. This…
Abstract
Purpose
The purpose of this study is to investigate the deposition of SS–Al transitional wall using the wire arc directed energy deposition (WA-DED) process with a Cu interlayer. This study also aims to analyse the metallographic properties of the SS–Cu and Al–Cu interfaces and their mechanical properties.
Design/methodology/approach
The study used transitional deposition of SS–Al material over each other by incorporating Cu as interlayer between the two. The scanning electron microscope analysis, energy dispersive X-ray analysis, X-ray diffractometer analysis, tensile testing and micro-hardness measurement were performed to investigate the interface characteristics and mechanical properties of the SS–Al transitional wall.
Findings
The study discovered that the WA-DED process with a Cu interlayer worked well for the deposition of SS–Al transitional walls. The formation of solid solutions of Fe–Cu and Fe–Si was observed at the SS–Cu interface rather than intermetallic compounds (IMCs), according to the metallographic analysis. On the other hand, three different IMCs were formed at the Al–Cu interface, namely, Al–Cu, Al2Cu and Al4Cu9. The study also observed the formation of a lamellar structure of Al and Al2Cu at the hypereutectic phase. The mechanical testing revealed that the Al–Cu interface failed without significant deformation, i.e. < 4.73%, indicating the brittleness of the interface.
Originality/value
The study identified the formation of HCP–Fe at the SS–Cu interface, which has not been previously reported in additive manufacturing literature. Furthermore, the study observed the formation of a lamellar structure of Al and Al2Cu phase at the hypereutectic phase, which has not been previously reported in SS–Al transitional wall deposition.
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Hong Yuan, Jun Han, Huaqiang Lu, Junhui Li and Lan Zeng
Due to its inexpensive production costs, low stress concentration and maintenance-friendliness, the adhesive bonded pipe joint is frequently utilized for pipe connection. However…
Abstract
Purpose
Due to its inexpensive production costs, low stress concentration and maintenance-friendliness, the adhesive bonded pipe joint is frequently utilized for pipe connection. However, further theoretical analysis is needed to understand the debonding failure mechanism of such bonded pipe joints under axial tension.
Design/methodology/approach
In this study, based on the bi-linear cohesive zone model, the integrated closed-form solutions were derived by considering the axial stiffness ratio and failure stage to determine the relative interfacial slip, interfacial shear stress and relationship of tension–displacement in the bonded pipe joint.
Findings
Additionally, solutions for the critical bonded length and the ultimate load capacity were put forth. Besides, the numerical study was conducted to verify the theoretical solutions regarding the load–displacement relationship. The interfacial shear stress distribution at different failure stages was presented to understand the interfacial shear stress transmission and debonding process. The effect of bonded length on the ultimate load and ductility of pipe joints was also discussed.
Originality/value
The findings in this study can give a reference for the design of bonded pipe joints in their actual engineering applications.
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