Hybrid Connectors Research Articles

Snail-inspired robotic swarms: a hybrid connector drives collective adaptation in unstructured outdoor environments

Terrestrial self-reconfigurable robot swarms offer adaptable solutions for various tasks. However, most existing swarms are limited to controlled indoor settings, and often compromise stability due to their freeform connections. To address these issues, we present a snail robotic swarm system inspired by land snails, tailored for unstructured environments. Our system also employs a two-mode connection mechanism, drawing from the adhesive capabilities of land snails. The free mode, mirroring a snail’s natural locomotion, leverages magnet-embedded tracks for freeform mobility, thereby enhancing adaptability and efficiency. The strong mode, analogous to a snail’s response to disturbance, employs a vacuum sucker with directional polymer stalks for robust adhesion. By assigning specific functions to each mode, our system achieves a balance between mobility and secure connections. Outdoor experiments demonstrate the capabilities of individual robots and the exceptional synergy within the swarm. This research advances the real-world applications of terrestrial robotic swarms in unstructured environments.

Zavisnosložene klauze sa značenjem eksceptivnosti u administrativno-pravnom stilu srpskoga jezika 19. veka

The aim of the paper is to examine the status of dependent clauses with the meaning of exclusion in the administrative-legal style of the Serbian language in the 19 th century. The meaning of exclusion within the category of dependent clauses develops as a product of the more recent language development, mostly in the 20th century, and there has been no research on the status of this category in the 19th century as well as in the administrative-legal style of the 20th century. Legal texts adopted during the 19th century were used as the corpus. Excerpted examples were analyzed using a combina- tion of semantic-syntactic, historical-linguistic, and functional-stylistic methods. We found that dependent clauses with exceptional meaning represent the least numerous group of dependent clauses in the administrative-legal style of the 19th century. This meaning is expressed by connectors such as osim ako / osem ako, sem ako, osim kad, osim gde, samo što and krom(j)e kad. The connector krom(j)e kad is found in the pre-standard period and represents the only hybrid connector, with a combination of elements from the vernacular and Church Slavonic / Russian-Slavic language. For the pre-standard period, it can be said that most connectors are in the process of formation. The connector samo ako, which in the normative-legal code serves to encode the exception within the rule-exception matrix, is most common.

Tensile behaviour of the dissimilar friction stir welding between pure copper and aluminium 1050

Copper-aluminum hybrid connectors play a crucial role in electric vehicles, but welding these metals together poses a significant challenge due to their distinct physical and mechanical properties. Friction stir welding, a solid-state welding technique, proves to be suitable for joining dissimilar metals. In this study, friction stir welding was employed to create a joint between pure copper 1100 and aluminum 1050 plates, each with a thickness of 5 mm. The fabricated results showed that a significant amount of copper was dispersed into the aluminum side to establish the bonding. The bonding strength was evaluated through tensile testing, while the macrostructure and fracture paths of the joints were monitored using an optical microscope. Despite efforts, eliminating defects in the joint proved challenging, with most defects attributed to vacancies. Increasing the tool rotation speed resulted in greater mixing intensity between the aluminum and copper. The interface between the copper and aluminum was found to be prone to crack propagation. The tensile strength of the joint improved with higher tool rotation, reaching up to 88 MPa. For further analysis, stress within the joint under tensile loading was simulated.

Push-out test of hybrid shear connector in steel-precast UHPC composite slab

This paper presents an experimental investigation on the shear behavior of steel and Ultra-high Performance Concrete (UHPC) composite slab connected by different connector types including epoxy resin adhesive, headed stud, and their hybrid. Thirty-two push-out tests were conducted and the failure mode and load-slip cure of specimens were tested. The influences of parameters including the connector type, bonding area, number of headed studs and loading mode on the shear resistance of hybrid connector were explored. The shear transfer mechanism, composite effect and shear resistance of the stud and epoxy resin adhesive for hybrid connector were discussed. The epoxy resin adhesive and headed studs in hybrid connector showed steel interface debonding and stud shrank failures. The ratio of shear resistance for studs to epoxy resin adhesives exerted a great influence on the slip performance and shear resistance of hybrid connector. The composite effect depends on whether the studs bear the load firstly. An equation was proposed by taking factors including the composite effect and loading mode. The predict results showed high correlation with the experimental ones.

Preliminary Design of a Steel–UHPFRC Composite Truss Arch Bridge and Model Tests of K-Joints

The preliminary design and comparisons of major technical and economic indicators between a steel-ultrahigh-performance fiber-reinforced concrete (UHPFRC) composite truss (SUCT) arch bridge and a concrete-filled steel tubular (CFST) arch bridge with both spans of 375 m are carried out in this study. Compared with the CFST arch bridge, the SUCT arch bridge can improve the durability of the bridge and has advantages in terms of steel consumption, self-weight, carbon emission, and other indicators due to the use of UHPFRC with high compressive strength as the arch ribs to bear the large axial forces. Adoption of the cyclic construction method for the SUCT arch bridge with two closure processes results in a total cost basically equivalent to that of the CFST arch bridge. For the K-joints in the connection area of the UHPFRC arch ribs and steel web members, a new hybrid connection form of “perforated shear connectors (PBL) + headed studs” is proposed. Loading tests in three directions in plane, pull-out tests, and parameter analysis are carried out. The experimental results show that the new hybrid connector is reasonable for the K-joints, which has advantages of large stiffness, short force transmission path, and high efficiency, and can ensure the continuity of steel fibers. Moreover, the new hybrid connector displays good shear performance, pull-out performance, and high bearing capacity. Based on the results of parameter analysis, the sensitivity of the pull-out bearing capacity to the three variables is compressive stress in the arch rib, followed by the tensile and compressive strengths of UHPFRC.

Mechanical behavior of GFRP-bamboo composite shear connections

Sustainable development has become an important and urgent topic for civil engineering. More and more green and renewable materials, like engineered bamboo, have been designed to work with other traditional building materials to utilize the ecological benefit and mechanical advantages. Nonetheless, few researches investigated the mechanical performance of the composite structure made of fiber-reinforced polymer and engineered bamboo. A new composite connection made of pultruded H-section glass fiber-reinforced polymer (GFRP) profile and engineered bamboo was proposed and studied by push-out tests to assess the shear performance. A total of 46 specimens with bolted, glue or hybrid connectors were tested to investigate the influence of the connection type, bolt diameter and spacing, as well as the bamboo thickness, on the strength and stiffness of GFRP-bamboo connections. The load-carrying capacity and shear stiffness were analyzed, and three types of failure modes were identified. When the bamboo thickness was 17 mm and 20 mm, a single plastic hinge was formed in the shear connectors, and the bamboo panels performed splitting and edge crushing failures. When the bamboo thickness was 34 mm and 40 mm, two plastic hinges formed in the connectors with embedment failure in the bamboo panels. Nonetheless, when using glue connection, brittle and undesirable failure occurred. When increasing the bamboo thickness from 17 mm to 34 mm, the average peak load increased from 67.52 kN to 100.64 kN, and the yield and ultimate loads both increased by about 49%. In addition, the results showed that hybrid connections were more effective than bolted and glue connections. The average peak load of hybrid connections increased by 42.72% and 13.16% compared to that connected with glue and bolts, respectively. The experimental results were compared with those calculated according to Eurocode 5-1995 and GB/T50005-2017, and it could be concluded that the formulas of the codes were not suitable for such shear connections due to the conservative design. To predict the nonlinear behavior of the specimens, the theoretical model based on Foschi formula was built. The analytical predictions showed good agreement with the test results in case of bolted connections. In a word, the shear performance and theoretical model of the proposed composite shear connections make it possible to predict the bending strength and stiffness of GFRP-bamboo composite beams, but the sharp drop of load-carrying capacity induced by the failure of glue connection needs more consideration and research.

Achieve the effective connection of FRP bars by blocking resistance and adhesive Force: Adhesive-Bolt hybrid joint

The usage of Fiber Reinforced Polymer (FRP) bars for internal reinforcement has significantly increased and the connection of FRP bars has also gradually attracted attentions over the last decades. In this study, a novel connector was developed namely adhesive-bolt hybrid connector. This connector connects FRP bar effectively depending on the blocking resistance and adhesive force mainly. Based on the requirement of structure and mechanical properties, the design method of this connector was given in terms of adhesive medium, blocking bolts, sleeves. Then, the connector for FRP bar was designed and the tensile test of the joint was adjusted to verify the validity of the design method. It was found that the failure mode was the tensile destruction of FRP bar, and the stress on the sleeve was minimal at the end of the connector, while the stress on the FRP bar was minimal at the center of the connector. The effective connection of the FRP bars was realized by the adhesive-bolt hybrid connector and the excellent tensile properties of FRP bars were ensured. Finally, the bilinear bond-slip model was selected to calculate ultimate tensile capacity. The reliability of the design method was further verified by comparing the theoretical results with the experimental results of the ultimate tensile capacity.

Flexural behaviours of one-way steel-concrete-steel sandwich panels with novel hybrid connectors: Tests and analysis

A steel-concrete-steel sandwich panel with novel hybrid connectors (SCSSP-HC) was proposed in this paper, and the flexural behaviours of the SCSSP-HC were obtained via conducting four-point bending tests. All the tested SCSSP-HCs exhibited the typical flexural failure mode with three specific failure types being categorized. The typical load–displacement response of the SCSSP-HC exhibited initial elastic stage, strength hardening stage and descending stage. In addition, the effects of faceplate thickness, spacing of headed stud, shear span and loading direction on the responses of SCSSP-HCs were quantitatively studied. The results indicated that the flexural resistance and elastic stiffness of the SCSSP-HC could be significantly improved via increasing the steel faceplate thickness and decreasing the shear span. However, the spacing of headed stud and loading direction had insignificant effect on the responses of the SCSSP-HC. Moreover, an analytical model was developed to predict the elastic stiffness, yielding moment and ultimate moment of the SCSSP-HC, and the accuracy of the analytical model was validated via comparing the analytical predictions with experimental results.

A Survey on Blockchain Interoperability: Past, Present, and Future Trends

Blockchain interoperability is emerging as one of the crucial features of blockchain technology, but the knowledge necessary for achieving it is fragmented. This fact makes it challenging for academics and the industry to achieve interoperability among blockchains seamlessly. Given this new domain’s novelty and potential, we conduct a literature review on blockchain interoperability by collecting 284 papers and 120 grey literature documents, constituting a corpus of 404 documents. From those 404 documents, we systematically analyzed and discussed 102 documents, including peer-reviewed papers and grey literature. Our review classifies studies in three categories: Public Connectors, Blockchain of Blockchains, and Hybrid Connectors. Each category is further divided into sub-categories based on defined criteria. We classify 67 existing solutions in one sub-category using the Blockchain Interoperability Framework, providing a holistic overview of blockchain interoperability. Our findings show that blockchain interoperability has a much broader spectrum than cryptocurrencies and cross-chain asset transfers. Finally, this article discusses supporting technologies, standards, use cases, open challenges, and future research directions, paving the way for research in the area.

A novel tests set-up for validation of connector models subjected to static and impact loadings

A novel test set-up is presented for validation of hybrid connector models between steel and aluminium components subjected to static and impact loading. The proposed components consisted of two hat profiles in steel and aluminium joined by adhesive bonding combined with self-piercing riveting. The geometry of the components was determined by numerical simulations in order to focus the behaviour on the connections under normal and shear dominated loading. The chosen components were tested under static and dynamic loading conditions in a 3-point bending setup. Different displacement measurement techniques were applied to reveal the specimens behaviour, including digital image correlation.Test results were applied to validate idealized numerical models of adhesive and self-piercing riveting connections.

WITHDRAWN: Implementation of low power one bit full adder with cadence tool

Abstract In this research paper, the one-bit low power hybrid adder circuit is developed by additional logic of direct polarization and the reverse polarization method (FSB / RSB) of the Complementary metal-oxidesemiconductor (CMOS) and Transmission Gate Logic (TGL). A full adder of 1-bit is proposed in 180 nm technology and the performance parameters, such as delays, strengths, and areas, are compared to such as CMOS, 10 T, 14 T, and Hybrid Connectors. The design uses a power supply of 1.8 V for 180 nm technology. Compared to other existing full additive designs, there is a better improvement in the strength of the proposed adder and PDP reference.

Mechanical Behavior of Hybrid Connectors for Rapid-Assembling Steel-Concrete Composite Beams

In order to achieve a kind of shear connector suitable for rapid-assembling steel-concrete composite beams, a new type of hybrid shear connectors is proposed, in which the concrete slab with prefabricated circular holes and the steel beam with welded studs are installed and positioned, and then epoxy mortar is filled in the prefabricated hole to fix the studs. To study the mechanical behavior of these hybrid connectors, test on 18 push-out specimens with different prefabricated circular holes are carried out. ABAQUS finite element software is adopted to verify the relationship between the numerical simulation and experiment, influences of the epoxy mortar strength and prefabricated circular holes diameter are studied. The results show that filling epoxy mortar in the prefabricated hole is beneficial to improve the stiffness and bearing capacity of the specimen; the change of epoxy mortar strength has a certain impact on the bearing capacity and stiffness of the hybrid connector; In the case of the same strength of the filling material, the size of the prefabricated circular holes diameter directly affects the stiffness and bearing capacity of the shear stud. The shear capacity equations proposed by considering the epoxy mortar strength and prefabricated holes diameter, and it has a wide applicability.

Analytical and numerical modeling of RC beam-column joints retrofitted with FRP laminates and hybrid composite connectors

This paper summarizes results on an analytical and numerical simulation of structural behavior of reinforced concrete (RC) beam-column joints retrofitted with different types of fiber-reinforced-polymeric (FRP) composite laminates and hybrid connectors. In this study, non-linear numerical simulations for the behavior of reinforced concrete (RC) beam-column joints that were evaluated in another phase of this study. The behavior of a total of eight full-scale interior RC beam-column specimens were numerically evaluated. The interior reinforced concrete (RC) beam-column joint specimens were subjected to both simulated gravity and low-frequency full-cyclic reversal loads. For repair and external strengthening applications, three systems are evaluated including high-strength carbon/epoxy composite laminates, high-modulus carbon/epoxy laminates and E-glass/epoxy external laminates. For bond-slip retrofit, the light-weight hybrid composite connector, developed by the principal author, was evaluated through large-scale tests and is molded numerically. Good correlation between numerical and experimental results is achieved. A comparison between the numerical and experimental results are also presented.

Thermal performance of precast concrete sandwich walls with a novel hybrid connector

This paper presents the experimental and numerical studies on the thermal responses of precast concrete sandwich (PCS) walls with a novel hybrid connector. The hybrid connector is wrapped with nylon, which is shown to reduce the thermal bridge and improve the thermal performance of PCS wall. In the first part of this work, four PCS walls were fabricated for the experimental studies and the effects of hybrid connector, insulation layer thickness and insulation material on the thermal performances of PCS walls were experimentally evaluated. Then, the finite element (FE) method was adopted to conduct the heat transfer analyses on PCS walls. The accuracies of the FE models were verified via comparing the temperature and thermal transmittance versus time of PCS walls obtained from experiments and FE analyses. The FE models were subsequently used to investigate the effects of wrapped nylon, thermal conductivity, connector spacing, central rebar diameter and insulation layer thickness on the thermal performance of PCS walls. It was found that the thermal performance of PCS wall could be improved via wrapping the connector with nylon, reducing the materials’ thermal conductivities, increasing connector spacing and insulation layer thickness as well as reducing central rebar diameter.

Design and evaluation of a DIY construction system for educational robot kits

Building a robot from scratch in an educational context can be a challenging prospect. While a multitude of projects exist that simplify the electronics and software aspects of a robot, the same cannot be said for construction systems for robotics. In this paper, we present our efforts to create a low-cost do-it-yourself construction system for small robots. We have created three different construction systems (laser-cut screw connectors, printed friction-fit connectors, and printed hybrid connectors) using small aluminium T-slot extrusions, based on prior work done by Industrial Design college students. Eighty-six secondary school students and 35 teachers tested these three systems during a five-day robotics contest where they had to build firefighting robots. Follow-up questionnaires and an expert evaluation were used to measure the usability, affective appraisal and functionality of the three systems in order to determine which system should serve as a basis for further design iterations. Overall, a clear preference was shown for the hybrid system, which relies on its interlocking shape as well as on a screw connection to create robot frames that are both quick to construct and very rigid once assembled. We believe our work represents a solid first step toward an inexpensive, “hackable” construction system for educational robotics.

Redox-Active Organometallics: Magnetic and Electronic Couplings through Carbon−Silicon Hybrid Molecular Connectors

Treatment of the triflate complex Cp*(dppe)FeOTf [12; Cp* = eta(5)-C(5)(CH(3))(5), dppe = 1,2-bis(diphenylphosphino)ethane, OTf = CF(3)SO(3)] with an excess of HC[triple bond]C-(Si(CH(3))(2))(x)-C[triple bond]CH (x = 2-4) in diethyl ether provides the binuclear bis(vinylidene) derivatives [Cp*(dppe)Fe=C=CH(Si(CH(3))(2))(x)CH=C=Fe(dppe)Cp*][OTf](2) (x = 2, 13; x = 3, 14; x = 4, 15), which were isolated as ochre solids and rapidly characterized by FT-IR, (1)H, (31)P, and (13)C NMR spectroscopies. The complexes 13-15 were reacted with potassium tert-butoxide to afford the bis(alkynediyl) complexes [Cp*(dppe)Fe-C[triple bond]C(Si(CH(3))(2))(x)C[triple bond]C-Fe(dppe)Cp*] (x = 2, 1; x = 3, 2; x = 4, 3), which were isolated as orange powders in yields ranging from 76 to 91%. The IR, cyclic voltammetry, and UV-vis data obtained for 1-3 and the X-ray crystal structures determined for 1 and 3 reveal the importance of the sigma-pi conjugation (hyperconjugation) between the Si-Si sigma bond and the adjacent C[triple bond]C pi-symmetric orbitals in the description of the electronic structure of the ground state of these complexes. When reacted at low temperature with 2 equiv of [(C(5)H(5))(2)Fe]X or AgX [X = BPh(4), B(3,5-(CF(3))(2)C(6)H(3))(4))], compounds 1-3 provide 1[X](2), 2[X](2), and 3[X](2), which can be isolated and stored below -20 degrees C. EPR spectroscopy and magnetization measurements established that the superexchange interaction propagates through the Si-Si bonds (J = -0.97(2) cm(-1) for 3[X](2)). UV-vis-near-IR spectra were obtained with an optically transparent thin-layer electrosynthetic (OTTLE) cell for 1-3[OTf](n) (n = 0-2). A band with a maximum that increases from 6400 cm(-1) (1[OTf]) to 8500 cm(-1) (3[OTf]) observed for the mixed-valence species was ascribed to intervalence charge transfer evidencing photodriven electron transfer through the carbon-silicon hybrid connectors with H(ab) parameters ranging from 64 to 285 cm(-1).

Mixed finite elements based upon marguerre theory for the study of geometrically nonlinear behavior of thin shells

Simple triangular and quadrangular finite elements based on Marguerre's theory are proposed and are shown to greatly improve the solution over plane shell elements for a small additional computation cost. Several features of the developments are worth noting, namely: The presentation of a dual approach for the derivation of Marguerre's theory of shallow shells with moderate rotations, based on Fraeijs de Veubeke's variational principle, with a precise statement of hypotheses and applicability; the choice of hybrid connectors for solving the compatibility problem generated by Kirchhoff's hypothesis; a treatment of pressure loading, body forces and inextensional bending modes which employs a ‘static approach’ for the membrane; and discussion about the performance of some algorithms used to solve elastic stability problems. Numerical studies indicate that accurate results may be obtained by the approach advocated.