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1 – 3 of 3Zichao Liu, Wei Pan, Changhou Lu and Yongtao Zhang
This paper aims to establish an accurate mathematical model of a piezoelectric membrane restrictor that can be applied to control the shaft’s centerline orbit.
Abstract
Purpose
This paper aims to establish an accurate mathematical model of a piezoelectric membrane restrictor that can be applied to control the shaft’s centerline orbit.
Design/methodology/approach
The methodology uses three coupled equations to establish a mathematical model of the piezoelectric membrane restrictor – Reynolds equation, the membrane deformation equation and the flow rate equation. A data identification method is used to propose the flow rate formulas for the piezoelectric membrane restrictor.
Findings
It has been found that the structural parameters, the membrane center deformation and the inlet and outlet pressures of the piezoelectric membrane restrictor have an effect on the static performance of the restrictor. The identified flow rate result of the piezoelectric membrane restrictor is consistent with the models.
Originality/value
The paper provides an accurate mathematical model of the piezoelectric membrane restrictor which can also be applied to other membrane restrictors.
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Keywords
Waheed Ur Rehman, Xinhua Wang, Yingchun Chen, Xiaogao Yang, Zia Ullah, Yiqi Cheng and Marya Kanwal
The purpose of this paper is to improve static/dynamic characteristics of active-controlled hydrostatic journal bearing by using fractional order control techniques and optimizing…
Abstract
Purpose
The purpose of this paper is to improve static/dynamic characteristics of active-controlled hydrostatic journal bearing by using fractional order control techniques and optimizing algorithms.
Design/methodology/approach
Active lubrication has ability to overcome the unpredictable harsh environmental conditions which often lead to failure of capillary controlled traditional hydrostatic journal bearing. The research develops a mathematical model for a servo feedback-controlled hydrostatic journal bearing and dynamics of model is analyzed with different control techniques. The fractional-order PID control system is tuned by using particle swarm optimization and Nelder mead optimization techniques with the help of using multi-objective performance criteria.
Findings
The results of the current research are compared with previously published theoretical and experimental results. The proposed servo-controlled active bearing system is studied under a number of different dynamic situations and constraints of variable spindle speed, external load, temperature changes (viscosity) and variable bearing clearance (oil film thickness). The simulation results show that the proposed system has better performance in terms of controllability, faster response, stability, high stiffness and strong resistance.
Originality/value
This paper develops an accurate mathematical model for servo-controlled hydrostatic bearing with fractional order controller. The results are in excellent agreement with previously published literature.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0272
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Dongju Chen, Xuan Zhang, Ri Pan, Kun Sun and Jinwei Fan
This research aims to combine the throttling structure with the elastic element to enhance the load performance of aerostatic radial bearing.
Abstract
Purpose
This research aims to combine the throttling structure with the elastic element to enhance the load performance of aerostatic radial bearing.
Design/methodology/approach
In this research, a fluid–solid coupling model of the elastic throttling structure is established while considering the interaction between the elastic element and the flow field. The effects of elastic element structural parameters on the stiffness and load capacity of aerostatic radial bearing are then researched. Finally, the effect of elastic element modulus on air film load performance and elastic element deformation is analyzed.
Findings
The results indicate that the aerostatic radial bearing with elastic element can significantly improve the load capacity and stiffness when compared to the common aerostatic bearing. By choosing the proper combination of parameters, the load performance can be improved by at least 16%.
Originality/value
The throttling structure of aerostatic bearing is optimized in this work, which significantly enhances the load performance of the aerostatic bearing.
Details