Research On Billet Hanging Structure Optimization Based On The Non-probabilistic Reliability

Billet hanging is a special equipment for transporting the heavy, and it's widely. In design, processing, operation and other link of billet hanging, there is this large uncertain or controlled factor that influence design life and reliability of billet hanging. Consider the uncertainty itself, in this paper the interval finite element combining with the probability theory is applied to billet hanging reliability analysis. And main components and system reliability of billet hanging were analyzed. The optimization model merged into the non-probabilistic reliability index as a constraint may be solved by optimization method. That design method provided the strong theoretical support for billet hanging design. Therefore, the main research contents were list as following:(1) The structure non-probabilistic reliability based on interval analysis. Linked Interval analysis with structural reliability, the mapping relationship between the design parameters with a range of characteristics and structural response can be made known, and the non-probabilistic reliability index was described. By a example of plate-hole hanging lug, we analyzed the interval extension existing in interval arithmetic.(2) Combining the interval finite element method with non-probabilistic reliability theory, a method for analyzing structure non-probabilistic reliability based on the interval finite element was proposed. The method was used to solve the reliability problems of billet hanging, and a sensitivity factor based on the interval finite element for describing the influence degree of the uncertain parameters to structural response was defined. For solving the interval finite element equations, two methods that were the first order Taylor expansion method and the improved iterative algorithm were put forward. By virtue of them, we can obtain the fluctuation range of structure response, and combining with the definition of the non-probabilistic reliability index, we can estimate the reliability degree.(3) Combined with the interval finite element non-probabilistic reliability analysis method, assess the reliability of connecting rods, hanging beams and clamp arm of Billet hanging and analyzed the sensitivity of the uncertain parameters to structural response of them. First, when structure state function was implicit, taking connecting rob for example, we can obtain structure state function by use of the ability of support vector machine regression, and analyzed the reliability and sensitivity of it. Then, considering in strength, stiffness and stability failure modes of the hanging beam, we analyzed the structure reliability and sensitivity, and solved the interval finite element equations by global optimization algorithm, and got the range of structural response of hanging beams. Finally, based on the reliability and sensitivity of clamp arm, the best design value of uncertain parameters may be obtained by the optimization in different reliability index.(4) Putting forward the system non-probabilistic reliability analysis method for billet hanging, and optimizing the system of billet hanging based on the non-probabilistic probability reliability index. When billet hanging system is in a variety of failure mode, how to determine the main failure mode. We may find the main one in a variety of failure mode by the method of incremental load, then the system state equation may be built. According to the definition of non-probabilistic reliability index, the reliability of billet hanging system was analyzed. The results show, this method is convenient and simple, and it is more suitable for solving system reliability problems in practical engineering.