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As a high-temperature resistant damping material, reducing vibration by coating with M-shape metal rubber (MMR) in a pipeline system is a promising solution due to its energy dissipation induced by micro dry friction between metallic wires. The main challenge for dynamic calculation and performance evaluation of elastic-porous metal rubber (MR) is derived from the intricate spatial network structure. In this work, the dynamic properties including acceleration admittance and insertion loss of the MMR-coated pipeline system were conducted by numerical simulation and experimental analysis. The constitutive models used to characterize hysteresis phenomena, including Yeoh and Bergström–Boyce models, were identified with different density parameters and adopted for steady-state dynamic numerical analysis. The sine sweep frequency test was conducted to verify the accuracy of the developed numerical model. The results indicate that the maximum error of stress–strain curve between numerical prediction and experimental measurement is 10.7%. In the frequency range of 0–1 500Hz, the insertion loss of the MMR-coated pipeline system is positively correlated with the density of MMR, as opposed to the coating distance of pipeline clamps and the influence of excitation force is minimal. Furthermore, the error of dynamic response of the pipeline system in low frequency between the experiment and simulation is 4.7%, indicating that the accuracy of the hysteresis model in predicting the dynamic characteristic of MR materials is effective.

Ferroresonance is one of the most harmful and longest known power quality disturbances in the history of AC power systems. The ability of predicting transient and steady-state ferroresonance simulations mainly depends on the accuracy of the power transformer model. Most existing voltage transformer models apply single-valued nonlinear functions to represent the core nonlinearities. This study, based on our previous work, proposes a newly improved and accurate transformer iron core hysteresis model for ferroresonance simulation by extension of the classical arctangent model. To verify the proposed model’s accuracy and superiority, three different ferroresonant voltage and current waveform simulations were performed using both the proposed model and renowned EMTP Type-96 model under the same system parameters. In addition, simulation results were compared with the corresponding experimental measurements. The results indicate that the proposed model is easily implemented using numerical modeling method with good stability and convergence, and is sufficiently accurate for both transient and steady-state periodic ferroresonance analysis.

The paper deals with the inelastic analysis of infilled frames. It aims to appraise the effectiveness of existing member-by-member models and damage indices in representing seismic response and sustained damage. Results from pseudo-dynamic and cyclic tests on one-storey one-bay half-size-scale specimens are the basis for this evaluation. The frame is modelled with linear beam elements and hysteretic end springs, and the infill with diagonal struts for which two inelastic behavioural laws are compared. Provided parameters are carefully calibrated, time-histories of the global response can be traced with an accuracy that depends on model refinement. Certain indices reflect the visible damage of structure and infill. Nevertheless, if the structure index is derived from the calculated local response, not even the major damage of the weak beam is captured.

This paper explores the use of carbon fiber-reinforced elastomeric skins for advancing flexible morphing wing technologies, highlighting exceptional 1D morphing capabilities. The study focuses on synthesizing a specially engineered elastomer-based skin with a zero Poisson’s ratio, achieved through precise formulation and fabrication onto unidirectional carbon fiber. Poisson’s ratio of the 1D skin is confirmed to be zero via image analysis. Micro-CT tomography evaluates carbon fiber quality and voids under varied prestretch conditions, revealing proportional increases in void sizes. X-ray tomography also provides insights into void distribution and morphology during pre- and post-cyclic stretching. The innovative approach enables seamless 1D morphing, achieving an impressive 200% stretch with a slight increase in actuation force and hysteresis loss percentage. Inspired by continuum mechanics, the proposed “Exp-ln-ln” framework accurately models the loading–unloading stretching of the skin. An extensive parametric investigation assesses key parameters, advancing fiber-reinforced elastomeric materials for aerospace morphing skins.

Precision diamond turning based on a fast tool servo system utilized as a microdisplacement module is a very popular micro-structured surface manufacturing technology. Piezoelectric actuator is used as universal driving base of the FTS because of its high resolution and high stiffness but it exhibits hysteresis in response to an applied electric field, which not only considerably degrades the dynamic performance of the system but also leads to inaccuracy of the FTS system. This paper proposes a hysteresis model using RBF neural networks of FTS, based on the expanded input space method and applies closed loop control of FTS using the corresponding inverse model. A novel hysteresis operator is proposed to construct an expanded input space so as to facilitate the transformation of the multi-value mapping into a one-to-one mapping, enabling neural networks to approximate the behavior of hysteresis of FTS. The experimental results demonstrate that the measured displacement curves are in good agreement with the predicted curves, with a mean square error (MSE) of 5.1633e-6.