Triboelectric nanogenerators (TENG) have been reported with the advantages of high adaptability and easy integration in recent years, which, however, have been facing with the challenge of effective stimuli in different applications. In this study, we develop magnetic lifting triboelectric nanogenerators (ml-TENG) for energy harvesting and active sensing under cyclic loading, such as traffic. The ml-TENG take advantage of magnetic force to provide repulsive force to trigger for relative displacement between the electrode and dielectric layers in the sliding mode. Experimental and numerical studies are conducted to investigate the electrical performance of the ml-TENG under cyclic loading. The open-circuit voltage of 4 V and output power of 340 µW per capsule are obtained. In the end, we develop a self-powered velocity active sensing system using the ml-TENG, and the field test is conducted to obtain the maximum open-circuit voltage of 7.2 V at the velocity of 15 km/h. The reported ml-TENG provide a powerful tool to develop active sensing systems for real-world applications, such as velocity detection.

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Concrete cracking is the significant stage of RC structural deterioration induced by steel corrosion. To predict the corrosion-induced cracking of the loaded RC structure, a multi-scale model is proposed. The formation and transport of corrosion products, which affect the volumetric expansion at the steel–concrete interface, are considered in this model. Then, based on poro-mechanics, the calculation of corrosion-induced stress in the pore structure of concrete is enabled. The corrosion-induced cracking of the practical component obtained from the proposed model shows a satisfactory agreement with the experimental observations. Then, the corrosion-induced cracking under different loading conditions are investigated. The results show that the effect of external loads on the time-to-cracking is moderate; the steel corrosion varies by no more 9% under different loading conditions at the surface cracking moment, whereas significant effects of the loading condition on the cracking pattern of reinforced concrete beams are found. Furthermore, the higher the load level, the more rapidly the corrosion-induced cracks develop; the maximum corrosion-induced crack widths on the surface of the beam subjected to 60% ultimate load is 1.14 and 1.22 times that of the 30% and 0% loaded beams, respectively, when reaching the serviceability limit state.