An evaluation system of the eccentric orbit of shaft with aerostatic bearing in the microscale

2017 ◽  
Vol 232 (2) ◽  
pp. 155-165
Author(s):  
Dongju Chen ◽  
Jihong Han ◽  
Lihua Dong ◽  
Jinwei Fan ◽  
Chenhui An
Keyword(s):  
Evaluation System ◽  
Optimization Design ◽  
Dynamic Stiffness ◽  
Test System ◽  
Displacement Sensor ◽  
Aerostatic Bearing ◽  
Evaluation Standard ◽  
Shaft System ◽  
Control Equation ◽  
Orbit Model

In order to improve the machining precision of the aerostatic bearing, an eccentric rotor orbit model considering the microscale effects is established. A flow factor Q embodying the effects in the microscale is introduced into the fluid control equation, the dynamic stiffness, and damping coefficients of bearing are calculated considering the microscale effects. According to the actual working condition of the shaft, the modal analysis in both cases (with and without the microscale effects) is performed. And with the modal information, the dynamic orbit in both states (with and without the microscale effects) is described by the deduced orbit model of the shaft system. Finally, experiments of the frequency by LMS vibration test system and shaft orbit by displacement sensor are measured, and the results indicate that the simulated results considering the microscale effects are more similar with the actual experimental one, which provides a guideline and evaluation standard for further optimization design and precision control of the shaft system.

Experiment Analysis about Mechanical Properties of Rubber Bushing for Suspension Telescopic Shock Absorber

2014 ◽  
Vol 670-671 ◽  
pp. 1008-1011 ◽  
Author(s):  
Li Ping Li
Keyword(s):  
High Frequency ◽  
Optimization Design ◽  
Shock Absorber ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Test System ◽  
Test Results ◽  
Static And Dynamic Characteristics ◽  
Rubber Bushing

The experiments of static and dynamic characteristics of rubber bushing for rear suspension telescopic shock absorber were carried out at four directions such as axial, radial, torsion and yaw, by MTS831 and SAGINOMIYA test system. The tests prove that: rubber bushing has great damping, and rubber bushing has obvious nonlinear characteristic; the dynamic stiffness under low frequency and large amplitude excitation is smaller, while the dynamic stiffness under high frequency and small amplitude excitation is greater; at the same amplitude, the dynamic stiffness increases with the increasing excitation frequency. The test results can provide support for the optimization design of rubber bushing.

scholarly journals Study on Dynamic Characteristics of Aerostatic Bearing with Elastic Equalizing Pressure Groove

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Xiao-long Zhao ◽  
Hao Dong ◽  
Zhou Fang ◽  
Deng-di Chen ◽  
Jun-an Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Coupling Model ◽  
Damping Coefficient ◽  
Aerostatic Bearing ◽  
Equivalent Damping ◽  
New Type ◽  
Equivalent Damping Coefficient ◽  
Control Equation

Microvibration has an important influence on the dynamic performance of aerostatic bearings. Dynamic stiffness and equivalent damping coefficient are the main indexes to evaluate the dynamic characteristics of the aerostatic bearing. In order to study the dynamic characteristics of a new type of aerostatic bearing with the elastic equalizing pressure groove (EEPG), the dynamic characteristics of the new type of bearing are studied by theoretical calculation and experiment. First, the dynamic gas-solid coupling control equation is established. Then, the steady term and the perturbation term are decomposed by the perturbation method. By solving the coupling model, the dynamic characteristics of the bearing are calculated and analyzed. The calculation results show that the perturbation frequency has a significant effect on the dynamic stiffness and equivalent damping coefficient of the aerostatic bearing with EEPG. The dynamic stiffness increases with the increase of frequency, and the equivalent damping coefficient decreases with the increase of frequency. The experimental results are basically the same with the theoretical results, which effectively verify the correctness of the theoretical analysis.

Design of Road Test and Evaluation System for Vehicle Handling and Stability

2014 ◽  
Vol 505-506 ◽  
pp. 281-285
Author(s):  
Ming Qiu Gao ◽  
Run Qing Guo ◽  
Rong Liang Liang
Keyword(s):  
Data Processing ◽  
Test Data ◽  
Evaluation System ◽  
Test System ◽  
Stability Test ◽  
Road Test ◽  
Vehicle Handling ◽  
Test And Evaluation ◽  
Test Result

Vehicle handling and stability has effect on positive safety of automotive directly. Test system of handling and stability is built for its road test and the test variables signal can be acquired and stored synchronously. Based on MATLAB GUI, software is developed for the test data processing, so that the stored data is to be analyzed and handling and stability test result is given by the software automatically. Using the test system in paper, handling and stability road test of one domestic sedan is fulfilled and scored, which verifies the applicability of the test system and scoring software in paper.

Design on Hierarchical Testing System for Unmanned Ground Vehicles

2011 ◽  
Vol 346 ◽  
pp. 817-822 ◽  
Author(s):  
Xin Li ◽  
Guang Ming Xiong ◽  
Yang Sun ◽  
Shao Bin Wu ◽  
Jian Wei Gong ◽  
...  
Keyword(s):  
Evaluation System ◽  
Test System ◽  
Unmanned Vehicles ◽  
Intelligent Vehicles ◽  
Test Method ◽  
Unmanned Ground Vehicles ◽  
Ground Vehicles ◽  
Test Environment ◽  
Test And Evaluation ◽  
Comprehensive Test

The test system for technical abilities of unmanned vehicles is gradually developed from the single test to comprehensive test. The pre-established test and evaluation system can promote the development of unmanned ground vehicles. The 2009 Future Challenge: Intelligent Vehicles and Beyond (FC’09) pushed China's unmanned vehicles out of laboratories. This paper proposed to design a more scientific and comprehensive test system for future competitions to better guide and regulate the development of China's unmanned vehicles. According to the design idea of stage by stage and level by level, the hierarchical test content from simple to advanced, from local to overall is designed. Then the hierarchic test environment is established according to the levels of test content. The test method based on multi-platform and multi-sensor is put forward to ensure the accuracy of test results. The testing criterion framework is set up to regulate future unmanned vehicle contests and to assess the unmanned vehicles scientifically and accurately.

A study on accumulator analysis for the valve performance evaluation system of nuclear power plants

Kerntechnik ◽  
2021 ◽  
Vol 86 (1) ◽  
pp. 39-44
Author(s):  
K. Ryu ◽  
T. Lee ◽  
D. Baek ◽  
J. Park ◽  
N. Kim
Keyword(s):  
Latent Heat ◽  
Temperature Difference ◽  
Evaluation System ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
High Capacity ◽  
Test System ◽  
Performance Evaluation System ◽  
High Temperature Steam

Abstract To evaluate the valves used in the nuclear power plants are working properly under the required conditions, the performance and capacity test should be performed. In the test system, the accumulator was employed to control the large amount of high pressure and high temperature steam generated in the boiler precisely. In the accumulating process, the steam is often condensed. In order to prevent condensation, it is needed to install heaters and preheat the accumulator. However, if the size of the accumulator becomes large, the installation of the heater may not be easy. Therefore, when the test is conducted, the system was preheated by the latent heat generated from the phase change. Insufficient thermal insulation may cause temperature differences and it can cause mechanical problems in the accumulator structure. If insulation is sufficient, the temperature difference is indicated by the height. As the cooled condensate moves downwards, the condensate is discharged by the drain valve control and the temperature difference of the structure can be disappeared. The results of this paper can be applied to the conceptualization of equipment that uses latent heat and for the design of high-precision steam experimental devices or the design of high-capacity steam utilization systems.

Defective Pipeline Fatigue-Life Prediction Using Failure Assessment Diagram Technique

2004 ◽  
Author(s):  
Jinheng Luo ◽  
Xinwei Zhao ◽  
Qingren Xiong ◽  
Chunyong Huo
Keyword(s):  
Fatigue Life ◽  
Evaluation System ◽  
Life Prediction ◽  
Safety Evaluation ◽  
Load Ratio ◽  
Test System ◽  
Full Scale ◽  
Oil Pipeline ◽  
Failure Assessment Diagram ◽  
Failure Assessment

The life prediction, whose results can be used to define the inspection, repair or replacement cycle of in-service pipeline, is a main component of safety assessment of gas and oil pipeline. At present, failure Assessment Diagram (FAD) technique has been widely used in quantitative engineering safety evaluation system of pipeline that contains crack-like flaws. In past work, the authors developed a very useful model to predict the fatigue life of defective pipeline and established a computer calculating method. Based on FAD technique, toughness ratio and load ratio are calculated repeatedly with every crack increment in the model. With the self-developed full-scale test system, the full-scale pipe fatigue test was collected to verify the applicability of this method.

scholarly journals Displacement Investigation of KNN-Bitumen-Based Piezoceramics in Asphalt Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Ning Tang ◽  
Kaikai Yang ◽  
Wenhao Pan ◽  
Limei Wu ◽  
Qing Wang ◽  
...  
Keyword(s):  
Asphalt Concrete ◽  
Electromechanical Coupling ◽  
Asphalt Binder ◽  
Test System ◽  
Displacement Sensor ◽  
Research Focus ◽  
Vehicle Load ◽  
Piezoceramic Element ◽  
Piezoelectric Field ◽  
Natural Situation

Piezoelectric material has excellent characteristics of electromechanical coupling so that it could be widely applied in structural health monitoring field. Nondestructive testing of piezoelectric technique becomes a research focus on piezoelectric field. Asphalt concrete produces cumulative damage under the multiple repeated vehicle load and natural situation, so it is suited material and structure for nondestructive application. In this study, a test system was established by driving power of piezoceramic, laser displacement sensor, computer, and piezo-embedded asphalt concrete. Displacement, hysteresis, creeps, and dynamic behavior of KNN piezoceramic element embedded in asphalt concrete were tested. The results indicate that displacement output attained 0.4 μm to 0.7 μm when the loads were from 0 N to 150 N. The hysteresis was not obvious when the load was from 0 N to 100 N, aside from higher loads. The creep phenomenon can be divided into two parts: uptrend and balance. The more serious the asphalt binder ageing is, the larger the displacement is, when piezo-asphalt concrete has already been in serious ageing.

scholarly journals Dynamic Stiffness and Damping Characteristics of a Shaft Damping Ring: A Combined Hyperelastic and Viscoelastic Constitutive Model

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Miaomiao Li ◽  
Jian Chen ◽  
Rupeng Zhu ◽  
Cheng Duan ◽  
Shuai Wang ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Structural Parameters ◽  
Dynamic Stiffness ◽  
Constitutive Models ◽  
Operating Conditions ◽  
Uniaxial Tensile ◽  
Bending Vibrations ◽  
Damping Characteristics ◽  
Shaft System ◽  
Stiffness And Damping

At higher velocities, the helicopter tail transmission system encounters notable difficulties due to excessive bending vibrations. The shaft damping ring installed on the shaft system was shown to effectively suppress the shaft system vibrations. In this paper, the dynamic stiffness and damping characteristics of polyurethane shaft damping rings were studied using hyperelastic and viscoelastic constitutive models. The constitutive model and the damping ring material parameters were determined using uniaxial tensile and double-shear frequency scanning tests. Based on the test results, the dynamic damping ring characteristics were simulated and verified by dynamic stiffness tests; the influence of structural parameters and operating conditions on the dynamic stiffness and damping characteristics of the damping ring were obtained. The results provide a theoretical basis for the design of shaft systems with reduced sensitivity to vibrations.

Advancements in Machinery Management Using the Measurement of Rotor Torsional Response

1997 ◽  
Author(s):  
Alan S. Thomson
Keyword(s):  
Dynamic Stiffness ◽  
Management Tool ◽  
Large Deflections ◽  
Dynamic Motion ◽  
Torsional Response ◽  
Machine Failure ◽  
Shaft System ◽  
Lateral Forces ◽  
Torsional Excitation ◽  
Many Sources

Rotor torsional (angular, steady and dynamic) motion, in response to the interaction of torque and torsional/lateral cross coupled forces with torsional dynamic stiffness, exist in rotating and reciprocating machinery for many reasons. The dynamic torsional response however, is commonly not measured on a continual basis. In the torsional dynamic stiffness, damping parameters are generally several magnitudes weaker than their lateral counterpart. This yields the opportunity for torsional responses, especially when exciting a resonance, to produce relatively large deflections and corresponding stresses, sometimes large enough to cause machine failure. Due to their rigid coupling, long shaft system lengths (a series of shafts coupled together), and large polar moments of inertia, the turbomachinery used in the power generation industry are particularly sensitive to forced torsional excitation. The forcing can come from many sources, including lateral forces which cross couple into torsional forces. Recent research introduces new sources of cross coupled excitation and a method to indirectly measure their and other effects on the mechanical integrity of the mechanical system. A modified and a prototype technique for continuously measuring directly and indirectly the rotor torsional response, and using it to evaluate rotor torsional dynamic stiffness as a machinery management tool is discussed in this paper.

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