Method for evaluating characteristic life of metal structure of foundry crane based on track joint defects

Abstract

The invention discloses a method for evaluating the characteristic life of a metal structure of a foundry crane based on track joint defects. Through a rigid body motion dynamics model, an impact coefficient caused by the crane running on a joint track with high and low dislocation and horizontal clearance is calculated; a load spectrum according with engineering practice is compiled; an allowablestress method which is combined with finite element simulation is used for determining the fatigue dangerous section and dangerous point of the metal structure of the foundry crane, and a first principal stress-time history after dangerous point mutation caused by the track defects is obtained; a dual-parameter stress spectrum is extracted by adopting a rain-flow counting method, and combined with a Pairs formula in fracture mechanics, the service life and fatigue residual life of the dangerous point are calculated. Through a life characteristic assessment result, continued use, maintenance or scrapping of the foundry crane are judged, the security problem is solved that parent metal and weld failures are caused by foundry crane metal structure stress-time history mutation due to the carttrack defects, and a theoretical support is provided for the development of the national standard 'scrap conditions for foundry cranes'.

Description

technical field [0001] The invention belongs to the technical field of structure detection, and relates to a life evaluation method for judging the extended use, maintenance or scrapping of special crane equipment, in particular to a method for evaluating the life of cast crane metal structure features based on rail joint defects. Background technique [0002] There are 2.2 million cranes in service, one-third of which have been in service for 30 years, and the design life of the crane is about 30 to 50 years. Users are faced with the choice of extending, replacing or scrapping, and the game between economy and safety. There are huge challenges in the industry regarding the urgency of crane remaining life assessment needs and the lack of assessment standards, methods and means. [0003] Casting crane is one of the main equipments of steelmaking and continuous casting process. It has harsh working environment, high working level, complex structure and high safety requirements...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem in the prior art that the characteristic life of cast crane metal structures cannot be evaluated due to rail joint defects, the present invention discloses a method for evaluating the characteristic life of cast crane metal structures based on rail joint defects, which is mainly used to solve rail joint defects The problem of fatigue failure of structural base metal and weld cracking caused by the impact response of casting crane operation leading to the first principal stress-time history variation at the dangerous point on the dangerous section

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