scholarly journals Dynamics Test Research of Bounce of Carrier-Based Aircraft Arresting Hook

2020 ◽  
Vol 10 (24) ◽  
pp. 9033
Author(s):  
Yiming Peng ◽  
Pengpeng Xie ◽  
Xiaohui Wei ◽  
Hong Nie
Keyword(s):  
Test Data ◽  
Dynamic Performance ◽  
Horizontal Velocity ◽  
Test Method ◽  
Velocity Control ◽  
Stroke Length ◽  
Reliable Test ◽  
Test Process ◽  
Sinking Velocity ◽  
Bounce Height

The test of arresting hook bounce is one of the most essential technologies in the design and research of arresting hook. In order to research the dynamic performance of the hook after touchdown and impacting with the deck when the aircraft is arrested, an approach for a certain type of aircraft arresting hook bounce test is proposed in this paper. Solutions to critical technique issues arising in the test process such as aircraft sinking velocity control, aircraft horizontal velocity simulation, and simulation of the performance of the damper are derived and verified by the bounce test of the arresting hook. The bounce height, bounce distance, stroke length of the arresting hook damper after the hook is impacted are measured by the test. The test method proposed can be used for researching the bounce of arresting hook and providing reliable test data for the design of carrier-based aircraft and arresting hook.

Wire Adhesion Testing

1972 ◽  
Vol 45 (1) ◽  
pp. 16-25 ◽  
Author(s):  
L. C. Coates ◽  
C. Lauer
Keyword(s):  
Bond Strength ◽  
Physical Properties ◽  
Test Method ◽  
Material Strength ◽  
Basic Design ◽  
Rubber Compound ◽  
Reliable Test ◽  
Adhesion Testing ◽  
Rubber Compounds ◽  
The Relationship

Abstract The results of this study are conclusive. The ASTM D-2229 Test Method is not a reliable test for measuring adhesion of wire cords to rubber compounds. However, by using the basic design and modifying it, an accurate measurement of bond strength on a macroscopic level can be obtained. This test is insensitive for all practical purposes to compound physical properties and changes in cord diameter and embedded length—for both stranded and rod-like cords. It is also possible with this test to calculate the amount of stress that is exerted on the surface of the wire cord to determine the relationship between failing stress and the material strength of the rubber compound. Properly used, this new test should give the compounder a better tool to study the adhesion of compounds to metal.

scholarly journals Study on the Fatigue and Durability Behavior of Structural Expanded Polystyrene Concretes

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2882 ◽  
Author(s):  
Quan You ◽  
Linchang Miao ◽  
Chao Li ◽  
Huanglei Fang ◽  
Xiaodong Liang
Keyword(s):  
Cyclic Loading ◽  
Cyclic Load ◽  
Dynamic Performance ◽  
Plain Concrete ◽  
Expanded Polystyrene ◽  
Structural Elements ◽  
Sulfate Resistance ◽  
Erosion Test ◽  
Test Process

The fatigue and durability characteristics of structural expanded polystyrene concrete (EPS) are especially important when it was applied for structural elements in long-term service. In order to study the fatigue and durability behavior of structural EPS concrete, the long-term cyclic loading experiments and wetting–drying (W-D) cyclic experiments were conducted, respectively. The structural EPS concrete was found to have a relatively large damping and a fairly low dynamic elastic modulus under long-term cyclic load, which illustrated that it had a better energy absorption effect and toughness than plain concrete of the same strength level. Even if fine cracks appeared during the cyclic loading process, the relevant dynamic performance remained stable, which indicated that the structural EPS concrete had superior fatigue stability. In W-D cyclic experiments, the structural EPS concrete exhibited superior sulfate resistance. During the erosion test process, there was a positive correlation between the mass change and the evolution of the compressive strength of the structural EPS concrete, which indicated that ΔmB could be substituted for Δf to evaluate the degree of the structural EPS concrete eroded by sulfate attack. The study focuses on the fatigue performance and sulfate resistance of structural EPS concrete and is of important engineering value for promoting practical long-term operations.

Laboratory Comparison of Retroreflection Measurement System

2011 ◽  
Vol 308-310 ◽  
pp. 1041-1045 ◽  
Author(s):  
Wei Li ◽  
Chuan Zheng Zhu ◽  
Yong Yang
Keyword(s):  
Statistical Analysis ◽  
Test Data ◽  
Measurement System ◽  
Manufacturing Technology ◽  
Test Method ◽  
Measurement Systems ◽  
Safety Warning ◽  
National Test ◽  
Warning Effect

As the wide application of retroreflective materials, following problems such as safety warning effect, quality, manufacturing technology, test method become more and more important. Many national test centers or big manufactures build retroreflection measurement systems. In order to identify these laboratories’ ability, we organize this laboratory comparison. After 6 months experiments, this comparison successfully finishes. And all the test data are dealt with statistical analysis.

A New Dynamic Test Method of Fiber Optic Gyroscope

2012 ◽  
Vol 157-158 ◽  
pp. 245-249 ◽  
Author(s):  
Xu You Li ◽  
Na Zhang
Keyword(s):  
Input Signal ◽  
Fiber Optic ◽  
Dynamic Error ◽  
Dynamic Performance ◽  
Dynamic Test ◽  
Sine Wave ◽  
Test Method ◽  
Working Environment ◽  
Fiber Optic Gyroscope ◽  
Sway Motion

The sway motion of ships follows sine law. Therefore, it needs high dynamic performance of fiber optic gyroscope (FOG) to meet the serious working environment. A new test method was introduced to make reasonable assessment on the dynamic performance of FOG. The principle of this new test method was that the sine wave provided by the IP core in FPGA was superimposed on the digital ladder to simulate the input signal of sway motion. It could be proved that the serial of sine signal, which was generated by this method, was equivalent to the external input signal. Moreover, the dynamic error model of FOG was established to provide the theory of dynamic test. The results of dynamic test of FOG indicated that the dynamic error did not have divergent trends, the system parameters set was reasonable and the FOG system was stable. It also can be seen that dynamic error of FOG was increased with the increasing of sine wave amplitude, which was accord with the actual situation. The new dynamic test method of FOG was verified.

An ENOB Evaluation Method for an Acquisition Channel

2019 ◽  
Vol 28 (11) ◽  
pp. 1950185
Author(s):  
Xin Liu ◽  
Yan Liu ◽  
Zengshou Dong
Keyword(s):  
Evaluation Method ◽  
Golden Section ◽  
Dynamic Performance ◽  
Performance Testing ◽  
Sine Wave ◽  
Least Square ◽  
Test Method ◽  
Single Tone ◽  
Fitting Procedure ◽  
Dc Component

Three-parameter and four-parameter sine-wave fitting algorithms are powerful tools for estimating the parameters of the excited single-tone sine-wave for ADC. In the dynamic performance testing processes of instruments, the angle frequency, amplitude, phase and dc component of the input sine-wave are all unknown, so the fitting procedure is nonlinear. This paper proposes and analyzes a test method based on iteration Interpolated Discrete Fourier Transform (IpDFT) and sine-wave fitting method for evaluating the effective number of bit (ENOB) of the acquisition channel. Mathematical expressions of the Least-square fitting residual error and the proposed ENOB evaluation based on iteration IpDFT method are derived. These expressions are then particularized for acquisition circuit output noise composed of single-tone and additive white noise. Simulation results show that the DFT-based golden section searching algorithm (DGSSA) is an effective algorithm under coherent and non-coherent sampling conditions. The accuracy of the derived expressions and estimated parameters are verified through both the computer simulations and experimental results.

scholarly journals Problems of the dynamic test method for individual protection equipment (shock absorbers)

2018 ◽  
Vol 193 ◽  
pp. 05034 ◽  
Author(s):  
Dmitry Korolchenko ◽  
Vasily Vasilenko ◽  
Georgy Lelikov
Keyword(s):  
Dynamic Performance ◽  
Dynamic Test ◽  
Test Methods ◽  
Test Method ◽  
Testing System ◽  
Protective Properties ◽  
Shock Absorbers ◽  
Individual Protection ◽  
European Standards ◽  
Protective Performance

This paper examines issues of safety of high-altitude works, using individual protection equipment to prevent falling from a height. In particular, the paper reviews personal protective equipment - shock absorber, its dynamic characteristics and related test methods to meet the requirements of Technical Regulations 019/2011 “Safety of Individual Protection Equipment”. The paper discusses the differences between the Russian and European standards for dynamic characteristic testing of shock absorbers, even as the former are harmonized texts of the latter, and the effect of such differences on protective performance of shock absorbers and ultimately on safety of works on heights. It have been shown that tests, conducted in accordance with the Russian regulative documents for dynamic performance of the shock absorbers, entail decreasing in safety usage of such type of IPE and increasing in injuries during falls from a height. It has been defined necessity to actualize the range of the testing system of shock absorbers, and to admit its larger value that will cause increase in protective properties of shock absorbers.

Computational mechanical property determination of viscoelastic/plastic materials from nanoindentation creep test data

2009 ◽  
Vol 24 (3) ◽  
pp. 1245-1257 ◽  
Author(s):  
Jianjun Wang ◽  
Timothy C. Ovaert
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Finite Element ◽  
Test Data ◽  
Plastic Material ◽  
Test Method ◽  
Element Formulation ◽  
Unknown Parameters ◽  
Plastic Materials

Nanoindentation is a widely accepted test method for materials characterization. On account of the complexity of contact deformation behavior, design of parametric constitutive models and determination of the unknown parameters is challenging. To address the need for identification of mechanical properties of viscoelastic/plastic materials from nanoindentation data, a combined numerical finite element/optimization-based indentation modeling tool was developed, fully self-contained, and capable of running on a PC as a stand-alone executable program. The approach uses inverse engineering and formulates the material characterization task as an optimization problem. The model development consists of finite element formulation, viscoelastic/plastic material models, heuristic estimation to obtain initial solution boundaries, and a gradient-based optimization algorithm for fast convergence to extract mechanical properties from the test data. A four-parameter viscoelastic/plastic model is presented, then a simplified three-parameter model with more rapid convergence. The end result is a versatile tool for indentation simulation and mechanical property analysis.

Random Fatigue Limits of China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 347-351
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Z.G. Wang
Keyword(s):  
Test Data ◽  
Fatigue Cracks ◽  
Cast Steel ◽  
Test Method ◽  
Present Material ◽  
Steel Wheel ◽  
China Railway ◽  
Shrinkage Cavities ◽  
Random Fatigue

Random fatigue limits are experimentally studied on China grade B cast steel wheel. Test data were obtained by employing a so-called small sampling up-and-down test method. Results reveal that fatigue cracks of the present material were commonly initiated from the casting flaw of shrinkage cavities and grew with typical fatigue river-like flowers and striations. To address the scattered test data, randomness of fatigue limits are comparably measured by the existent four approaches, i.e. conventional, Dixon-Mood, Zhang-Kececioglu, and Zhao-Yang approaches. It is verified that Zhao-Yang approach is appropriately applied for the present assessment on random fatigue limits of China grade B cast steel wheel.

Dynamic Performance Characteristics of Floating-Ring Bearings With Varied Oil-Injection Swirl-Control Angles

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Daniel Tamunodukobipi ◽  
Chang Ho Kim ◽  
Yong-Bok Lee
Keyword(s):  
Test Data ◽  
Hydrodynamic Instability ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Efficient Solutions ◽  
Test Results ◽  
Clearance Ratio ◽  
Thermal Growth ◽  
Oil Injection ◽  
Sufficient Test

Hydrodynamic instability is a prime causative of performance irregularities and violent vibrations in floating-ring bearing (FRB) supported turbosystems. The quest for energy-efficient solutions to this has stimulated the development of diverse FRB design-geometries, dimensional relationships, and surface-contours. Unfortunately, these modifications are characterized mainly by model-predictors, which results lack sufficient test-data to benchmark their authenticities. This work presents the concept and the test-data of flow redirection in FRBs by using an oil-injection swirl-control mechanism (OISCM) to attenuate rotordynamic instabilities. FRBs with radius ratio = 1.75 and clearance ratio = 1.5 are tested for various OISCM angles (0 deg, 30 deg, and 60 deg) and under a specific load = 50 kN/m2. The test results indicate that FRBs with OISCM demonstrate substantial improvements in damping and stability characteristics. Their whirl-frequency-ratio (WFR) and cross-coupled forces are lower because of improved symmetry of films' pressure-forces (Kxx ≈ Kyy). Although the magnitudes of direct damping are higher (|Cxx| = 16.92 kN s/m for 60 deg and 6.03 kN s/m for 0 deg), the load capacity (Kxx) is slightly lower than the normal (0 deg), injection. Nonetheless, this discrepancy in load capacities becomes insignificant for speeds above 22 krpm. The WFR and subsynchronous amplitudes, which are graphic reflections of the bearing-based instability, become progressively smaller with increasing OISCM angle. However, this advantage at elevated speeds can only be sustained by a corresponding increase in oil-supply pressure to circumvent the advent of a starved inner-film and its attendant imbalance response and thermal growth. In closure, the OISCM bearing is more effective for mitigating rotordynamic instabilities in turborotors than conventional FRBs.

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