•Apply impressed current cathodic protection to parallel wires.•The rainwater used as electrode.•Acoustic emission used to study the test method.
The corrosion durability of bridge cables in ...operation is prominent. This study proposes an active protection method to apply impressed current cathodic protection (ICCP) to bridge cable parallel wires. The weight loss method, scanning electron microscopy, electrochemical test, and acoustic emission (AE) signal characteristic analysis were used to study the test method for electrochemical corrosion protection of cable parallel wires using rainwater conduction. Results show that cable wires are corroded on the surface and inside, whereas the cable wires with ICCP show different changes. The cable wires are effectively protected in the environment where a sodium chloride solution is used to simulate rainfall. In the AE test of the cable wires after corrosion using a signal generator, the main frequency of the AE signal gradually increases with the increase in corrosion degree. The high corrosion degree of the cable wires induces dispersion. The characteristics of AE signal can reflect the corrosion degree of the cable wires, and ICCP can decrease the corrosion rate of the cable wires.
•An easily-misleading formula for lateral force is deeply explored.•An analytical model, considering the discrete nature of cable wires, is proposed for analyzing the lateral forces between cable and ...saddle.•The effects of possible errors and key parameters on the lateral force are clarified.•The friction mechanism between cable and saddle is analyzed, proving the significant anti-slip potential of lateral friction.
Frictional resistance, typically provided by the bottom and sides of saddle, is essential for counterpoising unbalanced cable tension between adjacent spans. In most practices, however, the friction from the saddle sides is ignored due to the lack of an effective calculation method of lateral forces, giving rise to serious anti-slip issues, especially for multi-tower suspension bridges. For this reason, the lateral forces between the main cable and saddle are studied in this paper. A similar formula of lateral force in specification is first investigated to reveal its theoretical basis and limitations. Considering each cable wire as an individual discrete body, an analytical model with recursive algorithm is then developed, which allows to calculate the contact forces layer by layer. Based on this, the effects of possible errors are quantified, and the sensitivity of lateral forces to key parameters, such as friction coefficient, extra pressure, arrangement and diameter of the wires, is subsequently discussed in detail. The results show that the existing formula evolved from the Janssen theory is insufficient for anti-slip assessment of the main cable. The transverse gap of saddle trough has a limited increase effect on the lateral force. As the wire arrangement widens, the lateral force grows rapidly and then approaches a certain value. The lateral force is negatively related with the friction coefficient, and the extra pressure can create great yet regular influence on the distribution of lateral pressure. Finally, the Taizhou Yangtze River Bridge is taken as a case example for an application of the proposed model. It is found that 32.2% of the total friction comes from the lateral friction when two vertical friction plates are used, confirming that the anti-slip capacity of cable-saddle system can be greatly improved by adequately utilizing the lateral friction.
In the welding process of thick-walled titanium alloys, the selection of the wire type is one of the critical factors affecting the welding quality. In this paper, flux-cored and cable wires were ...used as filler materials in the welding of thick-walled titanium alloys. The macrostructure, microstructure, texture, and grain size of both welded joints were compared by employing an optical microscope (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM), and the tensile and impact properties were also evaluated. The comparison result showed that the fusion zone microstructure of both welded joints was dominated by a basketweave structure composed of interwoven acicular α' martensite, whereas the microstructure of flux-cored wire welded joints was finer, and the degree of anisotropy was low. The strength of both welded joints was higher than that of the base metal, ensuring that fracture occurred in the base metal area during tension. The Charpy impact energy of the flux-cored wire welded joint was 16.7% higher than that of the cable wire welded joint, indicating that the welded joint obtained with the flux-cored wire performed better in the welding process of thick-walled titanium alloys.
Background: A quantitative model was developed and applied for analyzing the correlation between hydrogen-induced corrosion cracking in both main cable wires and degraded stiffening of the girders of ...a cable suspension bridge, considering maintenance effects across time and space. Method: Bayesian inference is applied for predicting the correlations among the wires in the main cables owed to hydrogen-induced cracking (HIC) in the cable wires of a steel bridge, by using the improved hierarchical Bayesian models proposed here. Results: The simulated risk prediction under decreased strength of cable wires, due to the corrosion cracking, yields posterior distributions based on prior distributions and likelihoods. The Bayesian inference model can be applied to the design and maintenance of highly corroded and correlated components Data are updated through analyzed information from previous crack steps. A numerical example including not only reliability indices but also probabilities of failure for cable wires, damaged by HIC, is then presented. Compared with a conventional linear prediction model, the one herein developed provides highly improved convergence and closeness to the analyzed data. Conclusion: The proposed model can be used as a diagnostic or prognostic prediction tool for the performance of corroded bridge cable wires with crack propagation, allowing the development of maintenance plans for mechanical components and the overall structural system.
This paper deals with the Hydrogen Induced Cracking (HIC) of wires in a cable of a suspension bridge. The main objective is to compare the safety of a bridge system locally and globally. In a ...deterministic analysis stage, HIC in cable wires is calculated in order to evaluate the local safety of the main cable of suspension bridge. In the local analysis, a decoupling technique has been developed for the evaluation of crack propagations in a wire section driven by the hydrogen diffusion to a wire section, in terms of two 2-dimensional finite element models. One is for the fracture analysis in a longitudinal section, and the other is for a hydrogen diffusion model in a horizontal section. In a stochastic analysis stage, an ultimate limit state function for the cracking in cable wires is considered for the local safety of main cable. Using the ultimate limit state, the reliability of time-dependent and crack depth-dependent HIC of a cable wire has been calculated in component and parallel system reliability analysis. Globally, a serviceability limit state based on the global responses of a stiffening girder is also evaluated. Based on the observed difference of safeties between the global and local behaviors of the suspension bridge system, the proposed solutions are discussed.
Based on FDTD theories and algorithms, through CST modeling and simulation, the article analyses the rules of nuclear electromagnetic pulse on loop cable coupling within the cavity. The following ...conclusions were obtained: for loop cable wires, when the polarization direction of the magnetic field in the cavity is perpendicular to the loop plane, the magnetic inductive current is maximum, and in the loop, the coupling current of the cable which is parallel to the direction of the electric field is maximum, and coupled energy on its cable is also proportional to cable resistance value. The conclusion provides the important basis for NEMP protection.
The coupling effect of dead load, vehicle load, wind load and corrosive environment in the main saddle causes bending tribo-corrosion-fatigue behaviors between the wires and the saddle material in ...the suspension bridge. A self-made wire test rig was developed for the bending tribo-corrosion-fatigue test between the wire and saddle material in 3.5% NaCl solution and ultrapure water. The tribological properties (friction coefficient, wear mechanism, wear profile, volume loss, etc.), electrochemical corrosion behaviors (Tafel polarization curve, Nyquist diagram) and effect of fatigue load were revealed. The interaction of tribo-corrosion-fatigue was quantitatively analyzed by different types of volume loss, and its mechanism was discussed. The results demonstrated that a synergy of the three becomes more significant with the increasing fatigue load.
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•A self-made test rig was employed to carry out the tribo-corrosion-fatigue test between the cable wire and saddle material.•The tribo-corrosion-fatigue behaviors of the wires under different cycles were presented.•The effect of fatigue load on tribo-corrosion-fatigue behaviors was explored.•Tribo-corrosion-fatigue interaction was quantitatively characterized.
•High-entropy alloys were successfully prepared by dual wire + CMT.•Combined cable wire + aluminum welding wire avoids the preparation problem of aluminum-containing combined cable wire.•Heat ...accumulation converts part of FCC to BCC.•The tensile strength of this high-entropy alloy exceeds 1000 MPa.
In this paper, a combined cable wire (CCW) composed of 7 wires and an aluminum welding wire are simultaneously used for arc additive manufacturing of non-equimolar Al-Co-Cr-Fe-Ni high-entropy alloy. The differences in microstructure and mechanical properties of the upper, middle, and lower parts of the high-entropy alloy were systematically studied. The results show that the sample contains FCC phase and BCC phase. With the increase of distance from substrate, the heat gradually accumulates, and apart of FCC (face centered cubic) is transformed into BCC (body centered cubic) in Al-Co-Cr-Fe-Ni high-entropy alloy. The increase of BCC improves the microhardness (from 281.86HV to 310.38HV), yield strength (from 514 MPa to 656 MPa) and ultimate tensile strength (from 916 MPa to 1087 MPa).
•Novel dual FCC phase Co-Cr-Fe-Ni-Cu-Mo HEA was designed and fabricated.•Combined cable wire is designed for additive manufacturing of HEA.•FCC HEA was greatly strengthened due to two phase ...structure.
FCC phase High-entropy alloys (HEAs) has excellent plasticity and toughness but low tensile property. To strengthen the HEA without plasticity reducing, Cu28.36 Ni22.32 Fe19.12Co15.17Cr12.26Mo2.77 HEA with dual FCC phase were successfully prepared by plasma arc additive manufacturing using a combined cable wire with multi-element composition. The results show that the prepared alloys were composed of Cu-poor FCC1 and Cu-rich FCC2, along with a small amount of Mo-rich precipitation phases. The ultimate tensile strength, yield strength is 531 MPa, 332 MPa, it is increased by 14.48 % and 32.75 % compared with arc melting technology with excellent elongation of 32.26 %. Compared with the vacuum induction melting technology, the strength is increased by 276.5 %. Dual phase obviously increased the mechanical properties. The Co and Cr element in the alloy is relatively low, which can reduce the production cost.
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