Importance-based Resilience Assessment and Optimization of Unmanned Ship Swarm System

Based on the unmanned ship swarm system, a resilience model for unmanned ship swarms is proposed by comprehensively considering the preventive indicators, robustness indicators, recoverability indicators, and reconfigurability indicators of the swarm system. Firstly, preventive and robust indicators are proposed based on the characteristics of the unmanned ship swarm system, and the improvement of system performance efficiency by redundant unmanned ships is established as a recoverability indicator. Then, reconfigurable indicators are proposed based on importance, and the resilience indicator of the unmanned ship swarm is determined. Finally, a numerical example is used to model and simulate the performance change and capricious process of the unmanned ship swarm. Most of the research on the resilience assessment model of unmanned ship swarms considered too single indicators. The model of the unmanned ship swarm under attack is constructed, and the superiority of the resilience optimization strategy proposed in this paper is verified

Testing and Evaluation of Flexural Tensile Strength of Prestressed CFRP Cables

To expand the application scope of prestressed carbon fiber-reinforced polymer (CFRP) cables in civil engineering, the ultimate tensile strength of these cables was tested and evaluated under bending conditions. First, the study analyzed the tensile failure mechanism of CFRP cables under bending conditions based on elastic bending analysis theory. Thereafter, the ultimate stress state of individual tendons and cables was derived and a calculation model for the tensile strength of bent CFRP cables was established. Second, 14 sets of test conditions were created for CFRP cables under bending angles of 20–40° and bending radii of 1.5–3 m. Then, bending tensile tests were conducted to evaluate the effects of the above factors on the ultimate tensile strength, and the correctness of the computational model was verified using experiments. Finally, the ultimate performance of CFRP cables was theoretically predicted using the established model. The results showed that the cable bending tensile strength was associated with the radius r, tensile strength f, and elastic modulus E of the reinforced material and the bending radius R, but was not correlated with the interface buffer material or the bending angle of the steering system. Moreover, the flexural tensile residual strength was only affected by R/r and E/f. When E/f involved conventional material parameters, the residual strength increased nonlinearly with increased R/r. When R/r ≥ 600, the residual strength reached more than 80%. Therefore, R/r at 600 could be used as the design basis for a safe critical radius

The Interfacial Friction Loss of Prestressed Carbon-Fiber Tendons in a Bending State

Carbon-fiber reinforced plastic (CFRP) is ideal for bridge reinforcement due to its high strength, light weight, and corrosion resistance. Studies on the friction loss of CFRP tendons in a bending state form an important part of advancing the application of CFRP materials to external prestressing strengthening technology. To understand the magnitude and variation of interfacial friction loss of prestressed CFRP tendons under bending conditions, 12 single-bending prestressing tension tests and 4 three-consecutive-bending prestressing tension tests were conducted in this study. Two bending radii of 1.5 m and 2 m, two bending angles of 20° and 30°, and three contact surfaces with different friction coefficients were selected for the steering block condition to measure the friction loss under each stage of tensioning prestress. On this basis, a model for calculating the friction loss rate on the surface of prestressed CFRP tendons was derived for the change of contact stress between CFRP tendons and deflectors during the installation and tensioning stages. The results show that the friction loss of external prestressed CFRP tendons is mainly related to four external factors: bending radius, steering angle, friction coefficient, and the magnitude of tensioning prestress; with the increase of prestress, the friction loss rate goes through three stages, the rising stage, the falling stage, and the stable stage; in the process of friction loss rate change, the main influencing factor controlling the magnitude of friction loss rate changes from bending radius to steering angle. In the theoretical calculation model of friction loss rate, the calculation model of the prestressed CFRP tendons under multiple successive bends can be simplified to a combination of several calculation models for a single bend. This study provides a reference for the engineering field of strengthening reinforced concrete (RC) beams using external prestressed CFRP tendons

CEPC Conceptual Design Report: Volume 2 - Physics & Detector

The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community to explore the Higgs boson and provide critical tests of the underlying fundamental physics principles of the Standard Model that might reveal new physics. The CEPC, to be hosted in China in a circular underground tunnel of approximately 100 km in circumference, is designed to operate as a Higgs factory producing electron-positron collisions with a center-of-mass energy of 240 GeV. The collider will also operate at around 91.2 GeV, as a Z factory, and at the WW production threshold (around 160 GeV). The CEPC will produce close to one trillion Z bosons, 100 million W bosons and over one million Higgs bosons. The vast amount of bottom quarks, charm quarks and tau-leptons produced in the decays of the Z bosons also makes the CEPC an effective B-factory and tau-charm factory. The CEPC will have two interaction points where two large detectors will be located. This document is the second volume of the CEPC Conceptual Design Report (CDR). It presents the physics case for the CEPC, describes conceptual designs of possible detectors and their technological options, highlights the expected detector and physics performance, and discusses future plans for detector R&D and physics investigations. The final CEPC detectors will be proposed and built by international collaborations but they are likely to be composed of the detector technologies included in the conceptual designs described in this document. A separate volume, Volume I, recently released, describes the design of the CEPC accelerator complex, its associated civil engineering, and strategic alternative scenarios

CEPC Conceptual Design Report: Volume 2 - Physics & Detector

The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community to explore the Higgs boson and provide critical tests of the underlying fundamental physics principles of the Standard Model that might reveal new physics. The CEPC, to be hosted in China in a circular underground tunnel of approximately 100 km in circumference, is designed to operate as a Higgs factory producing electron-positron collisions with a center-of-mass energy of 240 GeV. The collider will also operate at around 91.2 GeV, as a Z factory, and at the WW production threshold (around 160 GeV). The CEPC will produce close to one trillion Z bosons, 100 million W bosons and over one million Higgs bosons. The vast amount of bottom quarks, charm quarks and tau-leptons produced in the decays of the Z bosons also makes the CEPC an effective B-factory and tau-charm factory. The CEPC will have two interaction points where two large detectors will be located. This document is the second volume of the CEPC Conceptual Design Report (CDR). It presents the physics case for the CEPC, describes conceptual designs of possible detectors and their technological options, highlights the expected detector and physics performance, and discusses future plans for detector R&D and physics investigations. The final CEPC detectors will be proposed and built by international collaborations but they are likely to be composed of the detector technologies included in the conceptual designs described in this document. A separate volume, Volume I, recently released, describes the design of the CEPC accelerator complex, its associated civil engineering, and strategic alternative scenarios

CEPC Conceptual Design Report: Volume 2 - Physics & Detector

The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community to explore the Higgs boson and provide critical tests of the underlying fundamental physics principles of the Standard Model that might reveal new physics. The CEPC, to be hosted in China in a circular underground tunnel of approximately 100 km in circumference, is designed to operate as a Higgs factory producing electron-positron collisions with a center-of-mass energy of 240 GeV. The collider will also operate at around 91.2 GeV, as a Z factory, and at the WW production threshold (around 160 GeV). The CEPC will produce close to one trillion Z bosons, 100 million W bosons and over one million Higgs bosons. The vast amount of bottom quarks, charm quarks and tau-leptons produced in the decays of the Z bosons also makes the CEPC an effective B-factory and tau-charm factory. The CEPC will have two interaction points where two large detectors will be located. This document is the second volume of the CEPC Conceptual Design Report (CDR). It presents the physics case for the CEPC, describes conceptual designs of possible detectors and their technological options, highlights the expected detector and physics performance, and discusses future plans for detector R&D and physics investigations. The final CEPC detectors will be proposed and built by international collaborations but they are likely to be composed of the detector technologies included in the conceptual designs described in this document. A separate volume, Volume I, recently released, describes the design of the CEPC accelerator complex, its associated civil engineering, and strategic alternative scenarios