Control of Impact Loads on Aircraft Landing Gears Using Magnetorheological Fluid Dampers

使用磁流变流体阻尼器控制飞机起落架的冲击载荷

• 批准号: RGPIN-2014-04262
• 负责人: Bhat, Rama
• 金额: $ 1.75万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=566403
• 关键词: Control; Impact; Loads; Aircraft; Landing

Control of Impact Loads on Aircraft Landing Gears Using Magnetorheological Fluid Dampers: Shock absorbers in aircraft landing gears are required to absorb and dissipate the impact kinetic energy during landing so as to reduce the vibrations transmitted to the main aircraft body and to the passengers. The objectives of the proposed research are to study the performance of the landing gear system by using a magentorheological fluid damper in the system. The basic function of the shock absorber in aircraft landing gears is to absorb and dissipate the impact kinetic energy of the aircraft body frame during landing so as to reduce the vibrations transmitted to the main body of the aircraft to a tolerable level. Normally, oleo struts, which are essentially shock absorbers that have a fluid spring with gas and oil are used. Oleo-pneumatic shock absorber system is currently one of the most common in medium to large aircrafts, as it provides shock absorption as well as effective damping during landing and taxiing. During the compression process, the oil and gas either remain separated or are mixed depending on the type of design. After the initial impact, energy is dissipated as the air pressure forces the oil back into its chamber through recoil orifices. Most designs have a metering pin extending through the fluid flow orifice, which can vary the orifice area. This variation is adjusted by shaping the metering pin so that the strut load is fairly constant under dynamic loading. Once the metering pin is designed, the damping varies as a prescribed function of time to meet different loading conditions. However, it would be ideal if the damping could be varied according to the load and approach requirements such as for different weight of the aircraft or when the aircraft has different sink rate at the time of touchdown. During aircraft landing, the landing gears touch the runway with very little of the suspended mass of the aircraft transmitted to the runway because the aircraft wings still carry the bulk of the aircraft weight with the lift force. As the lift is slowly reduced after touch down, the apparent mass experienced by the landing gears changes as a function of time. The objective is to optimize the progressive reduction in the lift such that the aircraft experiences a constant deceleration in the vertical direction in order to ensure the structural integrity and ride comfort to the passengers. The scientific approaches for the above studies are (i) Analytical solutions to the equations of motion which is a system with time varying mass and damping properties, (ii) numerical simulation of the landing gear dynamics including the magnetorheological fluid dampers. Novelty and expected significance of the work to the aircraft industry: Magnetorheological fluid dampers change their damping property very rapidly by the application of a magnetic field across the MR fluid. The technology has been very successfully applied in vehicle suspensions in order to control the vehicle vibrations in a semi-active fashion. A similar vibration reduction can be achieved in aircraft structures also. The industries involved with the landing gears, such as Heroux Devtec Canada, Noramtec - Montréal, QC, Messier-Bugatti-Dowty, will benefit the most with the outcome of this research.

利用磁流变阻尼器控制飞机起落架上的冲击载荷：飞机起落架上的减振器需要吸收和消散着陆时的冲击动能，以减少传递给飞机主体和乘客的振动。提出的研究目标是通过在起落架系统中使用磁流变阻尼器来研究起落架系统的性能。飞机起落架减震器的基本功能是吸收和耗散飞机降落时机体框架的冲击动能，从而将传递到飞机主体的振动降低到可容忍的水平。通常情况下，油压支柱，本质上是减震器，它有一个含有气体和油的流体弹簧。液压-气动减震器系统是目前中大型飞机上最常见的减震器之一，因为它在着陆和滑行过程中提供减震和有效的阻尼。在压缩过程中，根据设计的类型，油气要么保持分离，要么混合。在最初的冲击之后，由于空气压力迫使油通过后坐力孔返回其腔室，能量被消散。大多数设计都有一个通过流体流动孔延伸的计量销，它可以改变孔的面积。这种变化是通过塑造计量销调整，使支柱的负载是相当恒定的动态载荷。设计好计量销后，阻尼随规定的时间函数变化，以满足不同的加载条件。然而，如果阻尼可以根据负载和进近要求而变化，例如飞机的不同重量或飞机在着陆时具有不同的下沉速率，那将是理想的。在飞机着陆时，起落架接触跑道时，很少有飞机的悬挂质量传递到跑道上，因为飞机的机翼仍然用升力承载着飞机的大部分重量。由于升力在着陆后逐渐减小，起落架所经历的表观质量随时间而变化。我们的目标是优化升力的逐步减小，使飞机在垂直方向上经历恒定的减速，以确保结构的完整性和乘客的乘坐舒适性。上述研究的科学方法是：(1)对具有时变质量和阻尼特性的系统的运动方程进行解析解，(2)对包括磁流变阻尼器在内的起落架动力学进行数值模拟。这项工作对飞机工业的新颖性和预期意义：磁流变流体阻尼器通过在磁流变流体上施加磁场，可以非常迅速地改变其阻尼特性。该技术已非常成功地应用于车辆悬架，以半主动方式控制车辆振动。在飞机结构中也可以实现类似的减振。与起落架相关的行业，如Heroux Devtec Canada， Noramtec - montrsamal， QC, Messier-Bugatti-Dowty，将从这项研究的结果中受益最多。