| “Energy saving and environmental protection” has increasingly become the focus of the whole society.The manufacturing industry’s goal is to produce more utility with less consumption.Nowadays,lightweight has become a development trend in the elevator industry.A feed roller line bracket of a certain type of continuous elevator with curved guide tracks for warehousing logistics was used as study object.Based on the 6σ robust design method,a research on the lightweight design method and the practical engineering application of elevator was carried out from the perspective of the lightweight parameter design of the roller line bracket.This research also took into account the reliability of the lightweight scheme and the robustness of the structural properties.The main research work are illustrated as follows:(1)Roller line bracket statics finite element analysis model was established to obtain the values of each performance index of the roller line bracket.Firstly,based on Solidworks software,ANSYS Workbench software and finite element numerical simulation technology,roller line bracket statics finite element analysis model was established.And then,the statics finite element analysis for the original model of the roller line bracket was carried out.It lays a foundation for the subsequent establishment of the response surface surrogate model of each performance index of the roller line bracket.(2)Based on second-order polynomial response surface model,the response surface surrogate model of each performance index of the roller line bracket were established to obtain the explicit expression of each performance index with respect to the design variables.Firstly,a strategy combined direct sensitivity analysis with relative sensitivity analysis was proposed to screen design variables.Then,the response surface surrogate model of weight,maximum equivalent stress and maximum deformation of the roller line bracket were built based on the central composite design,finite element numerical simulation technology and the least square method.Finally,the precisions of the constructed response surface surrogate model were tested.It lays a foundation for the subsequent establishment of the lightweight design model of roller line bracket based on 6σ robustness.(3)The traditional deterministic lightweight design result of roller line bracket is lack of reliability and robustness,so a lightweight design method of roller line bracket based on 6σ robustness was proposed to solve this problem.Firstly,the idea of building the lightweight design model based on robustness and reliability was summarized,the lightweight design process of roller line bracket based on 6σ was established,and the lightweight design model of the roller line bracket based on 6σ robustness was established.Then,the sequential quadratic programming method was adopted to solve this optimization problem.The reliabilities of the optimization results were calculated with the mean value second order and second moment method,and were transformed into corresponding σ levels.Finally,the verification of engineering feasibility of the optimization results was carried out,and the optimization results were compared with the traditional deterministic lightweight design results.The results show that the final lightweight scheme meets the reliability requirement,the robustness of maximum equivalent stress and maximum deformation are improved to a certain extent,the weight of the roller line bracket is reduced by 9.3kg and the weight loss rate reached 29.1%.Moreover,compared with the deterministic lightweight design,the lightweight design based on 6σ robustness not only lower the maximum equivalent stress and the maximum deformation to a certain extent,but also improves the reliability of the lightweight scheme,the robustness of maximum equivalent stress and maximum deformation.The drawback is that the weight is increased by 1.8kg.These results verify the effectiveness of the proposed method.This study provided a referential method for the lightweight design of elevators. |
