Journal of Advanced Mechanical Design, Systems, and Manufacturing (Nov 2019)
Remanufacturing decision-making method of jib structure based on characteristic life and strength redundancy
Abstract
For the damaged jib structure of mobile cranes in service, it is difficult for users to make a decision for using, repairing or scrapping and to achieve the balance of economy and security. The decision-making method of jib structure remanufacturing scheme is proposed based on characteristic life and strength redundancy and the decision-making system is developed. The damage location is divided into two regions according to failure modes. For the tensile stress region, test points with fatigue residual life are screened out. Then, with reliability theories consist of probability distribution fitting and goodness of fit test and adaptable double fruit fly algorithm being as the basis, the theoretical model of characteristic life reliability analysis of damaged jib section is built, and the fatigue life reliability of each detection point is obtained. Next, combined with the reliability threshold given in the original design, the remanufacturing scheme of each detection point is determined. For the compressive stress region, detection points entered into the repair admittance period is selected. On the basis of failure mode database, parameterized finite element model simulation computing platform and repair experimental data, the strength hierarchical analysis model of damaged jib section is established according to the generalized strength degradation process of jib structure. And the remanufacturing scheme of corresponding detection point is confirmed in combination with the minimum intensity redundancy factor. The remanufacturing scheme of damaged jib section is determined in the light of the remanufacturing scheme result set of various detection points. Taking the damaged jib structure of QY130t truck crane in service as an example, the feasibility and applicability of the method and system are verified.
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