Structural health monitoring (SHM) is an emerging technology that provides a high-resolution real-time damage state-sensing awareness and self-diagnostic capabilities enabled by a distributed sensor network. This technology is being used in the Industrial Internet of Things (IIoT) environment (a) to extend the duration of the service life of structural platfroms; (b) to increase their reliability; and (c) to reduce their maintenance and operational cost. This chapter discusses SHM systems, their design, sensor types, and usage through distributed sensing for reliable monitoring in IIoT applications. A distributed network of structurally integrated sensors for SHM diagnostics enables efficient real-time monitoring of entire structures. A carrier layer (SMART layer) is designed in such a way as to eliminate the need for each sensor to be installed individually in a structure. The layer consists of a network of distributed piezoelectric sensors that are individually bonded to it and is manufactured utilizing a standard flex-circuit construction technique in order to connect a large number of sensors. Advanced signal processing, diagnosis methods, and system hardware are implemented for damage monitoring in different complex structures such as rotorcraft, pipeline, paper manufacturing equipment, and high speed train.