Intelligent anti‑loosening bolt based on thermal expansion effect research on its application in electrical connections

This article proposes a new type of intelligent bolt structure that integrates thermal expansion material into the bolt head to achieve autonomous temperature regulation at the electrical connection. The bolt uses phosphate based ceramic composite material as the thermal conductive medium, and achieves axial expansion response within a temperature window of 75-200 °C through precisely controlled thermal expansion microspheres (Expancel 920DET80). Research has shown that this design can achieve an axial expansion rate of 23%, while controlling the radial expansion rate below 4%, and the axial compressive strength exceeds 18MPa. Experiments have shown that the bolt can achieve an axial expansion rate of 23% in the temperature range of 75-200 °C, reducing contact resistance by more than 40%, effectively solving the heating problem caused by loosening of traditional bolts in power systems.