Connector Model Research Articles

Study on the Draw Resistance Variation of CYO Connectors and Filter Rods

In order to study the law of draw resistance variation in the key parts of CYO (Connect Your Own) cigarettes, the draw resistance at the connectors and the filter rods was measured under ISO suction mode, and the relevant data were fitted. The equation of the suction resistance at the connector outlet (Z=30) was y=87344+87945*sin (pi* (x+38.5)/26.36). The equation of the draw resistance at the end of the filter rod (Z=0) was y=79879+80480*sin (pi* (x+36.8)/25.24). The trend of fitting curve is consistent with UDF equation. The suction resistance curves of the four connector models coincide with those of the blank filter rod model. It shows that the increase of splicer has no obvious effect on the draw resistance of smoke in the filter rod. In this paper, the smoking draw resistance equation of CYO cigarettes is proposed for the first time. It is of great theoretical significance for the further study of the law of smoking draw resistance variation between CYO cigarettes and key positions of filter rods and its influence on temperature change.

Mechanism and Validation of USB 3.0 Connector Caused Radio Frequency Interference

The mechanism of a universal serial bus 3.0 connector caused radio frequency interference (RFI) to a nearby antenna is studied. The connector radiation is modeled by an equivalent stripline-fed slot antenna, based on the analysis of the common mode current path on the connector structure. With the proposed connector model, the original connector radiation source can be replaced by an equivalent magnetic dipole source, which is directly correlated with the physical quantity on the connector. Applying reciprocity theorem, the equivalent dipole source can be applied to predict the coupled noise power to the antenna. The proposed connector radiation mechanism and model are validated through full-wave simulation and measurement. The application of the magnetic dipole source for RFI estimation is demonstrated in a real laptop system.

CHDC: Common Hospital Data Connector for exchanging medical information.

With the advance of technology, smart healthcare is emerging, and the amount of medical data is exploding. Currently, these large-scale medical data is scattered and stored in a variety of institutions. The data format is also different. These make medical data exchange difficult. Although there are many attempts to integrate EMR systems into a standardized structure, a high rate of EMR adoption in Korea using a standardized model such as HL7 RIM (Reference Information Model), attempts to replace systems that are already in use have largely failed due to a variety of causes, including time, cost and implementation manpower, and so on. In this paper, we propose a Common Hospital Data Connector model that has a way to integrate medical data without replacing the systems. This model defines what data should be extracted from the system with a variety of interfaces. These data profiles are based on statutory document and are able to be accepted in other medical institution. To ensure interoperability, the document is based on the international standard of Fast Healthcare Interoperability Resources and can be created in the form of a statutory document that can be printed. We applied this model to the hospital and verified that it can be used in actual services.

Mechanical behavior of high-strength bolts in T-stubs based on moment distribution

A T-stub is a component comprising a T-section with two bolts attached to its flange. It can be used to analyze the mechanical behavior of high-strength bolts in tension. In this study, the mechanical behavior of bolts was assessed via six static tests and 17 finite element analysis models. The effects of the thickness of the flange, the length of the inner and outer flange, and the diameter of the bolt were studied. With the exception of outer flange length, the parameters significantly affected the bolt bending moment, yielding load, and T-stub failure mode. Both the tests and the finite element analyses indicated that when the bolts yielded, the bending stress could reach 13% to 45% of the total tensile stress in the samples. It is not advisable to design bolts without considering the effect of the bending moment. A stable bending moment distribution relationship was also found between the bolt and the outer flange. The bending moment of the joint, the bending moment ratio of the bolt to the joint, and the distance from the contact force center to the bolt center are also discussed. Lastly, a new T-stub connector model and calculation method were proposed and proven to be reliable. This method is based on the theory of moment distribution and does not require the prying force to be calculated.

Automated synthesis of mediators for middleware-layer protocol interoperability in the IoT

To enable direct Internet connectivity of Things, complete protocol stacks need to be deployed on resource-constrained devices. Such protocol stacks typically build on lightweight IPv6 adaptations and may even include a middleware layer supporting high-level application development. However, the profusion of IoT middleware-layer interaction protocols has introduced technology diversity and high fragmentation in the IoT systems landscape with siloed vertical solutions. To enable the interconnection of heterogeneous Things across these barriers, advanced interoperability solutions at the middleware layer are required. In this paper, we introduce a solution for the automated synthesis of protocol mediators that support the interconnection of heterogeneous Things. Our systematic approach relies on the Data eXchange (DeX) connector model, which comprehensively abstracts and represents existing and potentially future IoT middleware protocols. Thanks to DeX, Things seamlessly interconnect through lightweight mediators. We validate our solution with respect to: (i) the support to developers when developing heterogeneous IoT applications; (ii) the runtime performance of the synthesized mediators.

Comprehensive atomistic modeling of copper nanowires-based surface connectors

In this paper, we study the mechanical behavior of surface nanoconnectors that are developed using two contacting sets of patterned copper (Cu) nanowire (NW) arrays. Specifically, comprehensive molecular dynamics (MD) simulations are conducted to establish the mechanics and the mechanisms involved at the atomic level that govern the mechanical integrity and ultimately the functionality of the formed bonds. All MD simulations were conducted using the embedded-atom and the Lennard-Jones potentials. Two aspects of the work were accordingly examined. The first considers the effect of temperature and diameter of an isolated Cu-NW on its tensile and fracture strength, as this determines the static strength and durability of the surface connector. The second considers the effect of NW diameter, separation distance between the NWs, overlapping depths, and temperature on the tensile strength of the nanoconnector. The results reveal that the formed surface joint between two interacting NWs can resist up to 70 nN in tension at an overlapping depth of 50 Å. It also reveals that increasing the nanowire diameter, the bonding failure becomes more surface dominated with insignificant plastic deformation outside the interface contacting region. These findings are useful in designing advanced conductive adhesives with tenable performance.

Sequential Buildup of Broadband Equivalent Circuit Model for Low-Cost SMA Connectors

This paper presents a measurement-based technique for equivalent circuit modeling of various types of SubMiniature version A (SMA) connectors. The 50- $\mathbf {\Omega }$ microstrip (MS) lines and conductor-backed coplanar waveguides are designed on high-frequency laminates. Three types of low-cost SMA connectors are mounted on the manufactured transmission lines. The presented technique for sequential buildup of the equivalent circuit model generates an equivalent circuit model of the SMA connector composed of ideal transmission lines and ideal lumped elements suitable for implementation in various circuit simulators. The SMA connector modeling is performed up to 12 GHz. The accuracy of the developed models is assessed by examination of the obtained $S$ -parameter results using the feature selective validation.

Strength and deflection behaviour of cold-formed steel back-to-back channels

Cold-formed steel (CFS) construction can lead to more efficient designs compared to hot-rolled steel members as a consequence of its high strength, light weight, ease of fabrication, and flexibility in their cross-section profiles. However, CFS members are vulnerable to local, distortional and overall buckling modes. This paper develops a numerical model to investigate the flexural strength and failure modes of CFS back-to-back channel beams and verifies the efficiency of an optimisation framework previously proposed. The model incorporates non-linear stress-strain behaviour and enhanced corner properties obtained from coupon tests, as well as initial geometric imperfections measured in physical specimens. To simulate the behaviour of a bolt bearing against a steel plate in the back-to-back section, a connector model is used that takes into account both slippage and bearing deformations. The developed Finite Element (FE) models are verified against six four-point bending tests on CFS back-to-back channel beams, where excellent agreement is found between the experimental results and the FE predictions. The validated FE models are then used to assess the adequacy of the effective width method in EC3 and the Direct Strength Method (DSM) in estimating the design capacity of conventional and optimum design CFS channel beam sections. The results indicate that both EC3 and DSM provide accurate predictions for the bending capacity of lipped channel beam sections. A comparison between FE predictions and tested results show that, the geometric imperfections can change the FE predictions of ultimate capacity by 7%, while the strain-hardening of CFS material at the round corners has negligible effects. It is also shown that EC3 uses a reduced cross-sectional property to calculate deflections, which can reasonably predict deflections with a slight overestimation (6%) at the serviceability load level.

Crestbond shear connectors for load transfer in concrete filled tube columns

Abstract This paper presents an experimental study with numerical modeling of Crestbond shear connectors in concrete filled tube columns. The Crestbond, which consists in a steel plate with regular cuttings, was originally conceived for composite beams and is now being proposed as an alternative device for load introduction and shear transfer at the steel-concrete interface in concrete filled tube columns. The results achieved in this work were very favorable to the new application proposed for the connector as high values of shear strength were obtained. Moreover, the numerical and experimental results enabled comparative analysis and investigations regarding the influence of concrete conditions and the geometry of the column section on the mechanical properties of the connector.

High-Frequency Characterization and Modeling of Coaxial Connectors With Degraded Contact Surfaces

Coaxial connectors provide a means to connect and disconnect transmission lines, components, and systems at high signal frequencies. Connector contact degradation has a significant effect on signal transmissions. This paper considers experimental measurements, simulations, and analyses of the high-frequency behaviors of degraded coaxial connector. An experimental investigation was first performed to evaluate how degraded contact surfaces affect the return loss and insertion loss of connectors. It was found that both the input return loss and the insertion loss are frequency-dependent. As the contact surface degrades, the return loss decreases and the insertion loss increases at lower frequencies, with the effect of the degradation becoming smaller with increasing frequency. A 3-D field simulation was developed to evaluate the high-frequency performance of various contact cases. Based on the simulation results, the electrical parameters of the dielectric film were extracted for connectors with different degradation levels. According to the transmission line theory and the contact physics, a high-frequency equivalent model of the degraded coaxial connector was developed and analyzed. This model is helpful in developing a better understanding of possible failure modes and in identifying failure features in fault diagnosis.

A 3D-FEM-based model to predict the electrical constriction resistance of compressed contacts

This work proposes a method to estimate the electrical constriction resistance of two mating metallic rough surfaces based on the finite element method (FEM). The FEM-based method generates a random array of three-dimensional orthogonal parallelepipeds to simulate the stochastic distribution of the asperities across the contact interface. The effect of the contact pressure is studied in detail, since once the contact materials and the topology of the contact area are settled, the contact pressure plays a critical role in determining the electrical constriction resistance. The proposed model is based on two critical variables, the contact pressure and the surface roughness of the mating surfaces, which must be measured in the laboratory to calibrate the model. Results provided by the FEM-based model are compared with experiments for three geometries, thus validating the accuracy of the proposed approach. Although the apparent contact areas of the analyzed specimens have a rectangular shape, the proposed method is also applicable to determine the electrical constriction resistance of other geometries. It is also proved that depending on the pressure applied to the contact interface, the electrical constriction resistance can be almost independent of the apparent area of contact. Although the aim of this work was to generate an electrical constriction resistance model for power connectors, it is also applicable to many other power devices.

Macro-modeling of spot weld strength and failure

PurposeThis paper aims to propose a macro modeling approach to simulate the mechanical behavior and the failure of spot welded joints in structural crashworthiness computations.Design/methodology/approachA connector element is proposed to simulate the behavior and failure of spot weld joints. An elastic-plastic damageable model is used to describe the non-linear response and rupture. The connector model involves several parameters that have to be defined. Some are directly identified based on mechanical interpretations and experimental tests characteristics. The remaining parameters are identified through a finite element model updating approach using Arcan tests. Resulting from a sensitivity analysis, an original two steps optimization methodology, using the Modes I and II Arcan tests results sequentially, has been implemented to identify the remaining model parameters.FindingsThe numerical results for Arcan tests in mixed Modes I/II are in a good agreement with the experimental ones. The model is also validated on tensile pull-out, single lap shear and coach-peel tests.Originality/valueBy comparison with previous published results, the proposed model brings a significant improvement. The main innovative aspects of this work are as follows: the proposed formulation, a reduced number of parameters to optimize, an original sequential optimization methodology based on physical and mechanical analyses and a mesh size independent connector element.

Modeling of shear walls using finite shear connector elements based on continuum plasticity

Light-frame timber buildings are often stabilized against lateral loads by using diaphragm action of roofs, floors and walls. The mechanical behavior of the sheathing-to-framing joints has a significant impact on the structural performance of shear walls. Most sheathing-to-framing joints show nonlinear load-displacement characteristics with plastic behavior. This paper is focused on the finite element modeling of shear walls. The purpose is to present a new shear connector element based on the theory of continuum plasticity. The incremental load-displacement relationship is derived based on the elastic-plastic stiffness tensor including the elastic stiffness tensor, the plastic modulus, a function representing the yield criterion and a hardening rule, and function representing the plastic potential. The plastic properties are determined from experimental results obtained from testing actual connections. Load-displacement curves for shear walls are calculated using the shear connector model and they are compared with experimental and other computational results. Also, the ultimate horizontal load-carrying capacity is compared to results obtained by an analytical plastic design method. Good agreements are found.

Deterioration in strength of studs based on two-parameter fatigue failure criterion

In the concept of two-parameter fatigue failure criterion, the material fatigue failure is determined by the damage degree and the current stress level. Based on this viewpoint, a residual strength degradation model for stud shear connectors under fatigue loads is proposed in this study. First, existing residual strength degradation models and test data are summarized. Next, three series of 11 push-out specimen tests according to the standard push-out test method in Eurocode-4 are performed: the static strength test, the fatigue endurance test and the residual strength test. By introducing the "two-parameter fatigue failure criterion," a residual strength calculation model after cyclic loading is derived, considering the nonlinear fatigue damage and the current stress condition. The parameters are achieved by fitting the data from this study and some literature data. Finally, through verification using several literature reports, the results show that the model can better describe the strength degradation law of stud connectors.

Derivation of design rules for innovative shear connectors in steel‐concrete composites through the systematic use of non‐linear finite element analysis (FEA)

AbstractToday, the development of innovative shear connectors for steel‐concrete composites is accompanied by a large number of experimental investigations, which are obligatory when proposing suitable design formula and carving out their limitations of use. Using the example of the so‐called pin connector, the present paper illustrates to what extent validated finite element models of novel shear connectors can be used to replace expensive and time‐consuming shear tests and how these finite element models can support the deduction of design concepts. The pin connector considered was developed for connecting steel sections to very slender high‐strength concrete slabs in which conventional shear connectors such as headed studs cannot be used due to the limited embedment depth. In order to clarify the shear behaviour and load‐carrying mechanisms of these novel connectors, non‐linear finite element models were set up using the commercial FE software Abaqus. Subsequently, the FE models were used to perform systematic parametric studies. This paper describes the numerical results and also explains the stepwise development of an entire engineering model for determining the longitudinal shear capacity of small‐scale pin connectors, including all the necessary limitations of use. The proposed modelling strategy and the methodology for the deduction of design rules can be transferred and assigned to other types of shear connectors.

Transient thermal modelling of substation connectors by means of dimensionality reduction

This paper proposes a simple, fast and accurate simulation approach based on one-dimensional reduction and the application of the finite difference method (FDM) to determine the temperatures rise in substation connectors. The method discretizes the studied three-dimensional geometry in a finite number of one-dimensional elements or regions in which the energy rate balance is calculated. Although a one-dimensional reduction is applied, to ensure the accuracy of the proposed transient method, it takes into account the three-dimensional geometry of the analyzed system to determine for all analyzed elements and at each time step different parameters such as the incremental resistance of each element or the convective coefficient. The proposed approach allows fulfilling both accuracy and low computational burden criteria, providing similar accuracy than the three-dimensional finite element method but with much lower computational requirements. Experimental results conducted in a high-current laboratory validate the accuracy and effectiveness of the proposed method and its usefulness to design substation connectors and other power devices and components with an optimal thermal behavior.

Physics‐based RF/microwave characterization of wave interactions within electrical connectors with partial insertion faults

AbstractElectrical failures in avionics systems may result from connector faults. If fault precursors are not detected in advance, they may lead to hard failures such as open and short circuits that could ultimately result in fire or loss of flight critical systems. Therefore, It is crucial to detect, locate, and characterize fault precursors for timely preventive maintenance and mitigation before hard failures occur. In this paper, a physics‐based connector model consisting of multiple coaxial line sections with different characteristic impedances and lengths is proposed. Method of Moments (MoM) analyses were performed using commercial electromagnetic simulation software, FEKO, for transverse electric and magnetic (TEM) wave propagation through a connector. The physical parameters of the connector were optimized to match the measured S parameters for multiple insertion depths. The proposed models represent the connector for multiple insertion depths by varying only two length parameters at a time while other parameters are fixed. Insertion depth‐dependent resonant frequency shifts observed during measurement are also captured by the model over the full range of fully inserted to barely touching contacts. Hence, the models provide accurate representations of the connector and properly detect precursors to partial insertion faults.

Experimental and numerical determination of compressive mechanical properties of multi-walled carbon nanotube reinforced polymer

Abstract In this paper, experimental and numerical methods were used to determine compressive mechanical properties of multi-walled carbon nanotube (MWCNT) reinforced epoxy. Standard samples with varying weight fractions of MWCNTs were prepared and were tested in compression. Nanocomposite modulus of elasticity, yield strength and compressive strength were determined experimentally. Experimental results show that incorporation of CNTs improves yield and compressive strengths of the epoxy resin to a large extent. Also, numerical simulation of nanocomposites was conducted in ABAQUS finite element (FE) software. In these simulations, the effects of the interface strength between individual nanotubes and between the outer nanotube and matrix were also investigated. Two different mechanisms were used to model these interfaces. In one set of the models, connector constraints were used as the interface. In the second set, an interface consisting of thin shells surrounding the nanotubes was used. The results of this investigation suggest that nanocomposite longitudinal modulus increases with increasing interface strength. Also, numerical results suggest that the connector model predicts values lower than the thin shell interphase model. Finally, experimental and numerical results were compared and a good correlation is observed between the results.

Determination of nonlinear behavior of multi-walled carbon nanotube reinforced polymer: Experimental, numerical, and micromechanical

In this investigation, nonlinear behavior of Multi Walled Carbon Nanotube reinforced epoxy resin is determined using experimental, numerical and micromechanical methods. Standard nanocomposite samples containing various weight fractions of MWCNTs were prepared and were tested. Experimental results show significant improvement in tensile and compressive mechanical properties of epoxy resin as a result of CNT addition. Compressive modulus of elasticity initially increased with nanotube content up to 0.45wt.%. At higher CNT weight fractions, compressive modulus decreased slightly. In addition, Field Emission Scanning Electron Microscope was used to obtain images of the samples' fracture surface. These images suggested a good CNT dispersion in the matrix. Numerical simulations are conducted to evaluate the nanocomposite elastic moduli using two different interface models. Numerical results suggest that the connector model predicts values lower than the thin shell interface model. Also, the elastic-plastic behavior of nanocomposites was estimated using a combination of micromechanical and numerical methods. To achieve this goal, micromechanical methods based on Mori–Tanaka and Halpin–Tsai models were used to predict the tensile stress-strain curves for the nanocomposites. In addition, nanocomposite compressive behavior was predicted using a combination of numerical and micromechanical methods. Finally, the numerical and micromechanical results showed good agreement with experimental measurements.

Load-slip behaviour of steel-cross laminated timber (CLT) composite connections

Connecting cross laminated timber (CLT) panels to steel girders using mechanical connectors (e.g. screws and bolts) is an attractive and novel method for developing a fully prefabricated and sustainable hybrid steel-timber composite (STC) floor that can also facilitate future dismantling and recycling of its structural components. Since the structural performance of composite floors (including STC systems) is significantly influenced by strength and stiffness of slab-to-girder composite joints, this study characterises the load-slip behaviour and failure modes of steel-CLT timber composite joints by conducting push-out tests on three different types of STC connections with high-strength bolts, coach screws or a combination of glue and coach screws. Furthermore, the effect of reinforcing the CLT slabs by using steel nail plates on the strength and stiffness of STC joints is evaluated. Empirical models for capturing load-slip behaviour of steel-CLT composite joints with dowel (i.e. screw and bolt) connectors are derived from non-linear regression of experimental data and simple formulae for the strength and stiffness of steel-CLT composite joints with dowel connectors are proposed. Moreover, 1D beam on inelastic foundation finite element (FE) models of the dowel STC connectors are developed and validated against experimental results.