Early prediction of fracturing failure for bolted joints based on enhanced metal magnetic memory

This paper aims to promote the engineering application of the metal magnetic memory (MMM) method, which is prone to interference from disturbing external magnetic fields. For this purpose, an enhanced MMM approach is proposed that highlights and enhances the useful magnetic signals through deliberate enhancement of the external field excitation, with the aim of improving the sensitivity and reliability of the detection system. Bearing in mind the non-linearity of the magnetic permeability curves for ferromagnetic materials, the feasibility of the enhanced MMM method is qualitatively analysed from a theoretical perspective and a real-time monitoring system is established to monitor the damage state of bolted joints based on the enhanced MMM method. The established system is then applied to the early prediction of the fracturing positions at the bolt holes. The results show that the enhanced MMM method can effectively and accurately predict the fracturing positions. The research findings lay a solid basis for the engineering application of the MMM method.