Our deteriorating civil infrastructure faces the critical challenge of long-term structural health monitoring for damage detection and localization. In contrast to existing research that often separates the designs of wireless sensor networks and structural engineering algorithms, this paper proposes a cyber-physical co-design approach to structural health monitoring based on wireless sensor networks. Our approach closely integrates (1) flexibility-based damage localization methods that allow a tradeoff between the number of sensors and the resolution of damage localization, and (2) an energy-efficient, multi-level computing architecture specifically designed to leverage the multi-resolution feature of the flexibility-based approach. The proposed approach has been implemented on the Intel Imote2 platform. Experiments on a physical beam and simulations of a truss structure demonstrate the system's efficacy in damage localization and energy efficiency.

The response surface (RS) method based on radial basis functions (RBFs) is proposed to model the input–output system of large‐scale structures for model updating in this article. As a methodology study, the complicated implicit relationships between the design parameters and response characteristics of cable‐stayed bridges are employed in the construction of an RS. The key issues for application of the proposed method are discussed, such as selecting the optimal shape parameters of RBFs, generating samples by using design of experiments, and evaluating the RS model. The RS methods based on RBFs of Gaussian, inverse quadratic, multiquadric, and inverse multiquadric are investigated. Meanwhile, the commonly used RS method based on polynomial function is also performed for comparison. The approximation accuracy of the RS methods is evaluated by multiple correlation coefficients and root mean squared errors. The antinoise ability of the proposed RS methods is also discussed. Results demonstrate that RS methods based on RBFs have high approximation accuracy and exhibit better performance than the RS method based on polynomial function. The proposed method is illustrated by model updating on a cable‐stayed bridge model. Simulation study shows that the updated results have high accuracy, and the model updating based on experimental data can achieve reasonable physical explanations. It is demonstrated that the proposed approach is valid for model updating of large and complicated structures such as long‐span cable‐stayed bridges.

The Debye sheath has a significant effect on the performance of Hall thrusters. The dynamic characteristics of the two-dimensional sheath is investigated using the 2D-3V particle-in-cell method in this paper. The numerical results show that while the sheath exhibits the one-dimensional stability when the electron temperature is relatively low, it behaves as a two-dimensional (both in time and space) oscillating characteristic when the electron temperature is high. Moreover, it is found that the oscillating frequency is the same order as the electron plasma frequency and the spatial wavelength is equal to the length of the electrostatic wave.

A two dimensional axisymmetric fully kinetic Particle-in-Cell/Monte Carlo Collision (PIC-MCC) model is used to describe the ignition process in a Hall thruster. A current peak and latter the periodic oscillation of current and electric potential are found. The corresponding evolutions of plasma density, electric potential and atom density during the ignition process are introduced in the paper. In addition, influences of mass flow rate and discharge potential on current peak are modeled and analyzed. The simulated results are consistent with former experimental results.

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