SUMMARY Small‐scale models have been commonly utilized in testing of performance of active mass driver (AMD) control systems. The utmost reason is that physical testing of AMD system at full scale is usually too expensive to afford, as well as hard to implement on site. With reference to the real‐time hybrid simulation technology, a real‐time AMD subsystem testing method is proposed in this paper. In this method, the entire system is composed of AMD as physical subsystem and target structure as numerical subsystem. The physical test is conducted on AMD subsystem, whereas the numerical simulation is carried out on the structure subsystem. Meanwhile, the real‐time data are being communicated between these two subsystems. This method is then applied to the performance validation of a novel AMD control system, which is driven by a linear motor. In the test, a benchmark three‐storey frame structure is employed as the numerical subsystem, and earthquake excitations are used as the external input. On the basis of a series of tests, both the time history and the statistical criteria show that the results of AMD subsystem and structure subsystem obtained in the real‐time AMD subsystem test agree well with the simulation results. Furthermore, all the test results show good repeatability. Therefore, the feasibility and reliability of the proposed real‐time AMD subsystem testing approach for performance validation of AMD subsystem has been demonstrated. Such kind of experimental method is efficient in terms of reducing cost associated with performance validation of large‐scale active control systems prior to the implementation. Copyright © 2013 John Wiley & Sons, Ltd.

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Smart aggregates (SAs) are often formed by embedding lead zirconate titanate (PZT) patches into concrete or marble blocks, which not only have the advantages of low cost, quick response, high reliability, and long service life, but also possess the comprehensive actuating and sensing abilities, and have been widely used in structural health monitoring in the field of civil engineering. However, due to the plate-like geometry of the PZT patch and the limited number of layers, the SAs have relatively short sensing range. To solve the problem of short sensing range, a new kind of smart aggregates using piezoelectric stacks was developed. Theoretical modeling of this new transducers was established, and three prototypes were fabricated. Comparisons between the theoretical predications and the experimental results were presented, and good agreements can be found. Effects of the key parameters, including the total height of specimen, the elastic modulus of cement, the radius of piezoelectric stack, the thickness of piezoelectric layer, and the number of piezoelectric layers in piezoelectric stack, on the electromechanical properties were analyzed, and the guidelines for optimal design were presented. In addition, the improved and the traditional SAs were used to monitoring the water content in the soil specimens based on the electromechanical impedance (EMI) technique. The results showed that the improved SAs using piezoelectric stacks is more sensitive than the traditional ones, which have promising potential in structural health monitoring in the field of civil engineering.

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Due to the problems of very serious wear, serious scale and poor ability to controlling strip shape of work roll, considering the advantages/disadvantages of HSS roll and the field practices, a 3D elastoplastic FEM model of rolls system with strip, which is used to analyze the ability of strip shape control of rolls system when HSS rolls work at any two stands of F1-F4, is modeled. The calculating results sho: The control ability of mill is relative greater when HSS rolls are used at F4, the advantages of HSS roll are not taken fully if HSS rolls work at F1 and F2. And HSS are available for either F2 or F3, furthermore, F3 is better for shape control. The analysis results are verified by the experiments. A strong theory base of application of HSS rolls in Hot Strip Mill is brought forward in this paper.