A Multistable Mechanism to Detect Thermal　Limits for Structural Health Monitoring (SHM)

摘要

This study proposes a novel multistable mechanism to detect thermal limits though harvesting energy fromthermally induced deformation. A detecting device is developed consisting of a bilaterally constrained beam equippedwith a piezoelectric polyvinylidene fluoride (PVDF) transducer. Under thermally induced displacement, the bilaterallyconfined beam is buckled. The post-buckling response is deployed to convert low-rate and low-frequency excitationsinto high-rate motions. The attached PVDF transducer harvests the induced energy and converts it to electrical signals,which are later used to measure the thermal limits. The efficiency of the proposed method was verified through anumerical study on a prestressed concrete bridge. To this aim, finite element simulations were conducted to obtain thethermally induced deformation of the bridge members between the deck and girder. In addition, an experimental studywas carried out on a 3D printed measuring device to simulate the thermal loading of bridge. In this phase, thecorrelation between the electrical signals generated by the PVDF film and the corresponding deck-girder displacementwas investigated. Based on the results, the proposed method effectively measures the mechanical response of concretebridges under thermal loading.