Debris Recognition Methods in the Lubrication System with Electrostatic Sensors

The oil-line electrostatic sensor (OLS) is a developing debris monitoring sensor. Previous work has shown that electrostatic charge signals can indicate the debris by calculating the Root Mean Square (RMS) value or the correlation-based indicator, but the precision of these methods is not high. This paper further developed the more accurate methods to obtain detailed debris information. Firstly, to interpret the monitoring principle of OLS and provide the guidance for developing the debris recognition methods, this paper analyzed the possible charge sources in the lubrication system and obtained the characteristics of the OLS by establishing its mathematical model. Further, a new OLS test rig was designed and verified the correctness of the sensor’s characteristics and its mathematical model. Based on the characteristics of the sensor, two new debris recognition methods were proposed. Finally, the effects of the new debris recognition methods were verified by the practical industrial gearbox bench test. Results showed that, compared to the traditional methods, the new methods could recognize the debris effectively and provide more detailed information of the debris.

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Experimental Validation of Numerical Model for Bi-Tilt-Isolator

Shock and Vibration ◽

10.1155/2018/7163516 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Ming-Hsiang Shih ◽

Wen-Pei Sung ◽

Chia-Yu Ho

Keyword(s):

Mathematical Model ◽

Root Mean Square Error ◽

Mean Square Error ◽

Root Mean Square ◽

Friction Force ◽

Polynomial Function ◽

Mean Square ◽

Test Results ◽

Cubic Polynomial ◽

Simulation Results

Bi-Tilt Isolator (BTI) is composed of bi-tilt beveled substrate and slider. The advantages of BTI are that the maximum upload seismic force of structure can be easily controlled and displacement of isolation layer will be reduced. Sliding force, friction force, and impulse force are caused in the slanting process of BTI, nonlinear behavior. A nonlinear mathematical model is derived based on the sliding upwards, sliding downwards, and transition stages. Then, BTI element of nonlinear analysis program, GENDYN, is developed by the fourth-order Runge-Kutta method, the discretized ordinary differential equation for three movement stages of BTI. Then, test set-up of superstructure installed with BTI is tested and recorded the real displacement and acceleration responses under conditions of full lubrication, mild lubrication, and without lubrication between interface of bi-tilt beveled substrate and slider with three various initial displacements. The comparison of simulation results and test results shows the following: (1) root mean square error is below 1.35% for WD40 sprayed, 0.47% for WD40 whipped, and 0.54% for without lubrication, respectively; (2) the maximum root mean square error for simulating with cubic polynomial function of friction is much less than those of constant friction except conditions of full lubrication, which are not affected by kinetic friction force; (3) application of cubic polynomial function for simulating friction of BTI with three different lubricated conditions can perform very fine simulation results, compared with the test results. This proposed mathematical model and BTI element of GENDYN program, using cubic polynomial function of friction, perform fine simulation capability to assess nonlinear isolation effect of structure installed with BTI.

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Stiffness Performance Simulation and Testing of a New Type Integrated Suspension Strut

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.472-475.2760 ◽

2012 ◽

Vol 472-475 ◽

pp. 2760-2765

Author(s):

Hao Bin Jiang ◽

Ying Jun Du ◽

Shen Chen Ye

Keyword(s):

Mathematical Model ◽

Fluid Mechanics ◽

Vertical Vibration ◽

Bench Test ◽

Test Results ◽

Performance Simulation ◽

Body Roll ◽

New Type ◽

Simulation Results ◽

Stiffness Characteristics

The design scheme of a new type strut was put forward, whose stiffness characteristics can undertake linkage control. The structure and basic principle of this new suspension component were introduced. According to fluid mechanics and thermodynamics, a mathematical model for the stroke dependent stiffness characteristics of the strut was established, and the stiffness characteristics were analyzed by using software SIMULINK. Then the stiffness performance bench test of the strut specimen was carried out for verification. Results show that the test results agree well with the simulation results. It is verified that the established mathematical model is correct and the stiffness of this strut shows nonlinear changes vary with the displacement of piston. When the suspension is largely impacted, the stiffness of this strut increases quickly which could restrain the wheel bouncing, body roll and vertical vibration.

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Design of iron bird for a regional jet aircraft

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410019879822 ◽

2019 ◽

Vol 234 (3) ◽

pp. 681-688

Author(s):

Dawei Li ◽

Mingxing Lin ◽

Liang Tian

Keyword(s):

Mathematical Model ◽

Fault Diagnosis ◽

Modular Design ◽

Test Validation ◽

Test Results ◽

Test Rig ◽

Design Improvement ◽

Test Systems ◽

Trouble Shooting ◽

Loading System

A regional jet’s iron bird was built for trouble shooting and design improvement of its airborne system. Modular design architecture and overall plan for the iron bird were proposed, and structure of the test rig, main tested systems, relevant supporting test systems and test programs were described. Besides, as one of the most critical airborne systems, NLG loading system was chosen for deep research; its mathematical model was built and analyzed in detail. Test results of hydraulic system’s main parameters were given. The whole iron bird provided important guarantee for system testing and continued design improvement. Also, test validation level for multi systems integration and fault diagnosis level of airborne system were improved.

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Estimation of Areal Mean Rainfall in Remote Areas Using B-SHADE Model

Advances in Meteorology ◽

10.1155/2016/7643753 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Tao Zhang ◽

Baolin Li ◽

Jinfeng Wang ◽

Maogui Hu ◽

Lili Xu

Keyword(s):

Root Mean Square ◽

Rain Gauge ◽

Unbiased Estimation ◽

The Tibetan Plateau ◽

Mean Square ◽

Traditional Methods ◽

Arithmetic Average ◽

Remote Areas ◽

Thiessen Polygon ◽

Mean Square Errors

This study presented a method to estimate areal mean rainfall (AMR) using a Biased Sentinel Hospital Based Area Disease Estimation (B-SHADE) model, together with biased rain gauge observations and Tropical Rainfall Measuring Mission (TRMM) data, for remote areas with a sparse and uneven distribution of rain gauges. Based on the B-SHADE model, the best linear unbiased estimation of AMR could be obtained. A case study was conducted for the Three-River Headwaters region in the Tibetan Plateau of China, and its performance was compared with traditional methods. The results indicated that B-SHADE obtained the least estimation biases, with a mean error and root mean square error of −0.63 and 3.48 mm, respectively. For the traditional methods including arithmetic average, Thiessen polygon, and ordinary kriging, the mean errors were 7.11, −1.43, and 2.89 mm, which were up to 1027.1%, 127.0%, and 358.3%, respectively, greater than for the B-SHADE model. The root mean square errors were 10.31, 4.02, and 6.27 mm, which were up to 196.1%, 15.5%, and 80.0%, respectively, higher than for the B-SHADE model. The proposed technique can be used to extend the AMR record to the presatellite observation period, when only the gauge data are available.

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Analysis of the Influence of Transmission Housing Elasticity on the Vibration Characteristics of Gear Shafting under Coupling Effect

Shock and Vibration ◽

10.1155/2021/9623119 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Hanlin Huang ◽

Shengping Fu ◽

Shanming Luo

Keyword(s):

Root Mean Square ◽

Coupling Effect ◽

Peak Frequency ◽

Vibration Characteristics ◽

Bench Test ◽

Maximum Speed ◽

Mean Square ◽

Lumped Mass ◽

Measuring Point ◽

Dynamic Reliability

The influences of transmission housing elastic deformations on the vibration gear shafting characteristics are studied. The vibration model of the vehicle transmission system in consideration of the dynamics coupling of the housing and the gear shafting is constructed. Aiming at a vehicle transmission, the mathematical model of the bending and torsional gear shafting vibrations is established based on the lumped mass method. Following the elastic treatment of the box, a comprehensive stiffness model at the bearing considering the housing deformation is proposed to achieve the dynamic coupling between the box and the gear shafting system. Furthermore, the gear shafting vibration characteristics considering housing deformations are obtained by integrating multisource dynamic excitation, which is solved using an iterative method. The results are verified through a bench test. And, it shows that the elastic deformation of the housing aggravates the gear shafting vibration (bending and torsional coupled vibration). The peak frequency mostly remains the same. The maximum speed changes amplitude and associated root mean square value (calculated at the gear position) increase by 55.5% and 59.6%, respectively. Next, the maximum bearing support force and its root mean square value are increased by 63.7% and 97.6%, respectively. Finally, the largest increase in maximum vibration acceleration at the measuring point and the simulated root mean square value are 90% and 63.1%, respectively. It is concluded that the research results provide a theoretical basis for the study of transmission dynamic reliability.

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Data Preprocessing of Magnetic Suspension Gyro-Total-Station by Vondrak Filter

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.2099 ◽

2013 ◽

Vol 671-674 ◽

pp. 2099-2102

Author(s):

Hui Ru Li ◽

Zhi Qiang Yang ◽

Zhen Shi

Keyword(s):

Mathematical Model ◽

Root Mean Square ◽

High Precision ◽

Data Preprocessing ◽

Magnetic Suspension ◽

Mean Square ◽

Total Station ◽

Maximum Extent ◽

Process Measurements ◽

Vondrak Filter

For Magnetic Suspension Gyro-total-station has vulnerable to outside interference factors, there are some random drifting containing in measurements which are unable to establish its mathematical model. Vondrak filter which does not require the model is used to pre-process measurements of Magnetic Suspension Gyro-total-station. In this paper a high-precision astronomical baseline is established in Xi'an, and the gyro azimuth is tested eight times in baseline. 40,000 north-seeking torque of the first and second place is filtered by the Vondrak filter for each test. The results show that the burr of data is reduced after filtered, and the filtered values reflect the trends of gyro north-seeking. Compared with the root mean square (RMS) of the measurements, RMS of Vondrak filter is decreased, the data is denser. Vondrak filter can effectively eliminate the random drifting containing in measurements, retain useful information in the maximum extent, and improve the accuracy of true north azimuth.

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