Research On The Relationship Between Cumulate Damnification Of Structure And Magnetism Memory Domino Offect

Any engineering structures inevitably exist damnification like tiny crack. The damnification reduces carrying capacity of structures. Even applied by static or slow loads, structures will rupture because of dynamic expanding of damnification. Traditional nondestructive test methods can only test defects that had grown shaped because of localization of the theory and technology, but traditional NDT can hardly estimate structures'early damnification like tiny crack, especially recessive discontinuity changes that still don't grow shaped. For reliably and sensitively testing early damnification, new theories and new instruments must be explored. The Magnetism Memory Test (MMT) technology offers a new nondestructive test method for nondestructive test field, and it can truly estimate security of equipments through early diagnosis, and it is the only nondestructive test method that can truly confirm stress concentration field on the tested object, and the stress concentration field is the id of the most danger zone. When MMT is used in locale, it is easy to confirm component's stress concentration field according to the stress concentration field's basic character, but there isn't a clear rule for bad degree of stress concentration, so MMT is restricted to use in practice. So this text aims at these questions, the tension experiment of a plate with a hole was done at the electronic universal testing machine, and vibration and turn experiment was done. Through these experiments the relationship of cumulate damnification with the Magnetism Memory domino offect is analyzed, and the Magnetism Memory signals of components are accurately estimated. Main work includes: 1. Simply review the developed summarization of Magnetism Memory test method. Introduce and appraise domestic and overseas development and study status quo of Magnetism Memory hardware and signal processing technology; 2. Study the mechanism of MMT technology. According to the microscopic construction of materials and combining the exchange theory and the energy zone theory, analyze recount integral factor. And combining the detailed thermodynamics deduction, the formula of piezomagnetism action is educed; 3. Analyze the relationship of cumulate damnification with the Magnetism Memory domino offect through these experiments. These experiments include tension experiment of a plate with a hole, vibration and turn experiment. Before experiments analyze stress of the plate with a hole and the plate's mode by software ANSYS, after experiments analyze test signals by software MMS and Origin; 4. Test steam turbine's vanes by MMT and analyze test signals. It is found that the Magnetism Memory technology is a valid method of diagnosing the steam turbine's vanes through test, and different rotor structure has different dangerous part. The dangerous parts of the rotor with straps primarily distribute in straps and the vanes'root of the end several classes; the dangerous parts of the rotor with tendons primarily distribute in tendons and the vanes'root of the end several classes, especially in the tendons.