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Piezoelectric materials that can effectively convert natural mechanical energy into electrical energy without time and space constraints have been widely applied for energy harvesting and conversion. The piezocomposites with high piezoelectricity and flexibility have shown great promise for renewable electric energy generation that can power implantable and wearable electronics. This minireview aims to summarize the recent progress of the piezocomposites with different composite structures, as well as the role of the theoretical understandings and designs in the development of new piezoelectric nanogenerator materials. Thereinto, the most common composite structural types (0-3, 1-3, and 3-3) have been discussed systematically. Several strategies for high output performance of piezocomposites are also proposed on the basis of current experimental and simulation results. Finally, the review concludes with perspectives on the future design of flexible piezoelectric nanocomposites for energy harvesters.

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Passive adaptive MR damper is a new type of damper based on GMM inverse effect and MR effect, and it doesn’t need energy devices and can realize external force self-adaptation. A model of passive adaptive MR damper is established based on Jiles-Atherton model, the law of approach for the magnetomechanical effect, the magnetic circuit law and Bingham model. Experimental results show that the value of damping force is related to displacement and velocity: the larger the displacement, the greater the damping force; the faster the speed, the greater the damping force. This is consistent with the model.

In the most of its engineering applications, ferroelectric materials are often subjected to combined loadings in the electric and mechanical fields. To simulate the influence of the biased stresses on the hysteretic dynamics of the materials, a macroscopic differential model is proposed to model the hysteresis loops and butterfly-shaped behaviors caused by the polarization orientation switching with biased stresses. A group of numerical simulations are presented, and the comparison of theoretical results with its experimental counterparts is also presented.