Research progress of flexible piezoresistive strain sensing technology in structural health monitoring

Flexible piezoresistive strain sensors have the advantages of large sensing range, excellent deformation adaptability, and good stability, which provide new approaches to solving the problems of the traditional strain sensors such as small range and low sensitivity, and show great application potential in the civil structural health monitoring (CSHM). In this paper, the common materials and basic sensing mechanisms of the flexible piezoresistive strain sensors were introduced. The state-of-art of three typical piezoresistive sensing principles was summarized in three aspects, including sensing mechanism, structural design and preparation method, and their applications in CSHM. The influences of material selection and conductive network optimization design on sensing performance control were analyzed. It is found that he use of composite conductive fillers and microstructure design can improve sensing performance. The development of high-performance and adaptable flexible piezoresistive strain sensors for engineering environments still faces problems such as material aging during long-term operation, unstable performance in engineering environments, and difficulty in system integration and maintenance. For the selection strategies of flexible piezoresistive sensors in CSHM, carbon-based conductive materials have better comprehensive performance, and flexible sensors with interface contact effect as the dominant mechanism are more suitable for strain monitoring needs of civil engineering structures. Finally, the prospect of the flexible piezoresistive sensors in intelligent operation and maintenance of civil engineering was presented. © 2024 Science Press. All rights reserved.