A New Design Model of an MR Shock Absorber for Aircraft Landing Gear Systems Considering Major and Minor Pressure Losses: Experimental Validation

Abstract

This work presents a novel design model of a magnetorheological (MR) fluid-based shock absorber (MR shock absorber in short) that can be applied to an aircraft landing gear system. When an external force acts on an MR shock absorber, pressure loss occurs at the flow path while resisting the fluid flow. During the flow motion, two pressure losses occur: the major loss, which is proportional to the flow rate, and the minor loss, which is proportional to the square of the flow rate. In general, when an MR shock absorber is designed for low stroke velocity systems such as an automotive suspension system, the consideration of the major loss only for the design model is well satisfied by experimental results. However, when an MR shock absorber is applied to dynamic systems that require high stroke velocity, such as aircraft landing gear systems, the minor loss effect becomes significant to the pressure drop. In this work, a new design model for an MR shock absorber, considering both the major and minor pressure losses, is proposed. After formulating a mathematical design model, a prototype of an MR shock absorber is manufactured based on the design parameters of a lightweight aircraft landing gear system. After establishing a drop test for the MR shock absorber, the results of the pressure drop versus stroke/stroke velocity are investigated at different impact energies. It is shown from comparative evaluation that the proposed design model agrees with the experiment much better than the model that considers only the major pressure loss.

Aircraft landing gear system with magnetorheological shock strut: Performance evaluation via drop test

“…In addition, it can be approximated as a parallel-plate flow when the ratio of inner and outer diameters of an annular flow path exceeds 0.8 (Lundgren et al, 1964). Based on the preceding conditions, both major and minor losses are considered in the compression condition (Kang et al, 2021a). Under the compression, the total pressure loss is as follows:…”

“…As a result of the analysis, the decision of is Σ K not significantly related to the flow path diameter but influenced by the flow path gap. The total loss is analyzed by referring to the CFD conditions and calculation formula (Kang et al, 2021a). The range of flow path gap d is limited to 1–2 mm and the analyzed result can be seen in Figure 6.…”

From Brush to Dendritic Structure: Tool for Tunable Interfacial Compatibility between the Iron-Based Particles and Silicone Oil in Magnetorheological Fluids

“…23,25 The remarkable rheological changes, including a transition from a liquid-like state to a solid-like state, occur within microseconds and are reversible. 26,27 The great controllability of the yield stress as a measure of the internal structure rigidity of MR fluids, dependent on the magnetic field strength, can be utilized in vibration control 28,29 but also in many other applications, e.g., brakes, 30,31 clutches, 32,33 dynamometers, 34 aircraft landing gears, 35 and helicopter lag dampers. 36 However, some drawbacks regarding MR suspensions limit their practical use, such as insufficient particles stability and their consequent sedimentation, poor oxidation stability resulting in thickening of the suspensions, and reduction of their magnetorheological performance.…”

Coupled Field Analysis of Phenomena in Hybrid Excited Magnetorheological Fluid Brake

“…Owing to their properties, MR fluids, in recent years, have been applied for their efficient control of torque and force transmission in new types of so-called magnetorheological transducers. They are very often used, among others, in the development of new types of brakes and dampers, as well as clutches [ 4 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ], offering an alternative way for controlling torque and force transmission in well-known electromechanical transducers. The magnetic field in the area with an MR fluid in the hybrid excited brake presented here is produced by both the arrangement of two windings and a system of permanent magnets ( Figure 1 ).…”

“…The research work conducted at these institutions focuses on the analysis of the operating states of existing devices and on methods to improve their functional performance. At the same time, work is also underway to develop new designs of devices [ 9 , 12 , 13 , 20 , 21 , 22 , 23 ]. In order to increase the accuracy of the obtained results of the analysis carried out for the operation states of electromechanical devices with an MR fluid, the rheological properties of the fluid, winding resistance, resistivity of massive conductive elements, and magnetic properties of materials must be considered as temperature dependent [ 24 , 25 , 26 , 27 , 28 ].…”