A Simple Performance Test for Evaluating End Hose Support Straps for Railroad Freight Cars

2011 ◽  
Author(s):  
Z. Liu ◽  
L. Hua
Keyword(s):  
Mechanical Properties ◽  
Performance Test ◽  
Reaction Force ◽  
Performance Testing ◽  
Drop Test ◽  
Test Results ◽  
The Real ◽  
Current Requirement ◽  
The Impact ◽  
Railroad Freight

A study has been performed to simulate the impact experienced on hose support straps during end hose separations on railroad freight cars. Analysis and comparison of test results of different hose straps show that the elasticity of the hose strap determines the reaction force generated by a certain impact. Under the same impact, a stiffer hose strap sustains a larger reaction force. Unlike the current requirement of AAR S-4006, the relation between the elasticity of the hose strap and its reaction force is not linear. Additionally, for a certain impact, the reaction force of the hose strap is only related to its mechanical properties, which reflects the real application. This study concludes that a simple drop test is adequate as an alternative method for performance testing of hose straps.

scholarly journals Inversion for Damping Ratio of Flat Blade Based on BP Neural Network

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 547
Author(s):  
Xiamei Zhang ◽  
Shudan Xia
Keyword(s):  
Neural Network ◽  
Decay Time ◽  
Bp Neural Network ◽  
Damping Ratio ◽  
Drop Test ◽  
Analysis Model ◽  
Bp Network ◽  
The Real ◽  
Neural Network Inversion ◽  
The Impact

Aero engine is impacted by foreign objects frequently during daily usage, including runway gravel, birds, fuselage components and so on, so the fan and compressor may damage, resulting in serious air crash. Thus, simulating the impact of blades and establishing the numerical analysis model of dynamic response demand immediate attention. In the analysis model, damping coefficient is one of the most important physical parameters of the blade structure and cannot be directly measured. Rayleigh damping is widely applied and can be converted to direct modal damping in ABAQUS. BP neural network is a multi-layer feedforward neural network using back propagation algorithm to adjust the network weights. It can be proved that there exists a three-layer BP network to realize the mapping of arbitrary continuous functions with arbitrary precision. In this study, a novel method for obtaining the damping ratio of the flat blade which applies BP neural network inversion is proposed. In order to demonstrate this method, a simplified experiment was conducted. Firstly, fix a section of aluminum plate and then conduct two set of drop tests on different positions with different impact velocities by a steel ball. At the same time, vibration response was recorded by displacement sensor. Secondly, establish a finite element model using ABAQUS to simulate the drop test. Adopt twenty groups of models with different damping ratio and then obtain their amplitudes and decay time, respectively. Thirdly, train a BP neural network using MATLAB program and then establish the mapping relationship between amplitude, decay time and damping ratio. Fourth, a set of experimental amplitude and decay time is substituted into the previously obtained BP neural network mapping model, and then the real damping ratio is obtained by inference. Finally, the real damping ratio is applied to the flat blade impact simulation of the other set of drop test for validation. The numerical results are consistent with the experimental data, which indicates that the damping ratio obtained by BP neural network inversion is reasonable and reliable.

scholarly journals Mechanical Performance of Unstitched and Silk Fiber-Stitched Woven Kenaf Fiber-Reinforced Epoxy Composites

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4801
Author(s):  
Yasir Khaleel Kirmasha ◽  
Mohaiman J. Sharba ◽  
Zulkiflle Leman ◽  
Mohamed Thariq Hameed Sultan
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Mechanical Test ◽  
Natural Fibers ◽  
Silk Fiber ◽  
Epoxy Composites ◽  
Test Results ◽  
The Impact ◽  
Woven Kenaf

Fiber composites are known to have poor through-thickness mechanical properties due to the absence of a Z-direction binder. This issue is more critical with the use of natural fibers due to their low strength compared to synthetic fibers. Stitching is a through-thickness toughening method that is used to introduce fibers in the Z-direction, which will result in better through-thickness mechanical properties. This research was carried out to determine the mechanical properties of unstitched and silk fiber-stitched woven kenaf-reinforced epoxy composites. The woven kenaf mat was stitched with silk fiber using a commercial sewing machine. The specimens were fabricated using a hand lay-up method. Three specimens were fabricated, one unstitched and two silk-stitched with deferent stitching orientations. The results show that the stitched specimens have comparable in-plane mechanical properties to the unstitched specimens. For the tensile mechanical test, stitched specimens show similar and 17.1% higher tensile strength compared to the unstitched specimens. The flexural mechanical test results show around a 9% decrease in the flexural strength for the stitched specimens. On the other hand, the Izod impact mechanical test results show a significant improvement of 33% for the stitched specimens, which means that stitching has successfully improved the out-of-plane mechanical properties. The outcome of this research indicates that the stitched specimens have better mechanical performance compared to the unstitched specimens and that the decrease in the flexural strength is insignificant in contrast with the remarkable enhancement in the impact strength.

Mechanical Nanocrystallization Surface Treatment on the Reheated 400MPa Ultrafine Grained Steel

2009 ◽  
Vol 79-82 ◽  
pp. 377-380
Author(s):  
Hong Yun Zhao ◽  
Guo Dong Wang ◽  
Chun Hua Xu ◽  
Feng Yuan Shu
Keyword(s):  
Mechanical Properties ◽  
Surface Treatment ◽  
Room Temperature ◽  
Performance Testing ◽  
Surface Form ◽  
Test Results ◽  
Ultrafine Grained ◽  
Before And After ◽  
Different Temperatures ◽  
Ultrafine Grained Steel

After reheated at different temperatures for 5 minutes, the 400MPa Ultrafine Grained Steel specimens were air-cooled to room temperature, and then carried out the mechanical nanocrystallization surface treatment and structure performance testing. On the basis of comparing the test results on the specimens before and after the mechanical nanocrystallization surface treatment, the process of mechanical nanocrystallization was analyzed briefly. The results show that: as the reheating temperature rising, the trend of grain size growing increases markedly, and the mechanical properties also drop down to different degrees; when the reheating temperature is around 800°C, because of the pearlite spheroidized significantly, its mechanical properties drop the most seriously; after the mechanical nanocrystallization surface treatment, not only its surface form a layer of fine nano-layer (about 100 nm) structure, but also its mechanical properties rise obviously, and the yield strength is over 450MPa.

Effect of various enzymatic treatments on the mechanical properties of coir fiber/poly(lactic acid) biocomposites

2019 ◽  
pp. 089270571986461
Author(s):  
Kubra Coskun ◽  
Aysenur Mutlu ◽  
Mehmet Dogan ◽  
Ebru Bozacı
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Coir Fiber ◽  
Test Results ◽  
Fiber Reinforced ◽  
Remarkable Effect ◽  
The Impact

The effects of enzymatic treatments on the properties of coir fiber-reinforced poly(lactic acid) (PLA) were not found in the literature. Accordingly, the effects of various enzymatic treatments on the mechanical performance of the coir fiber-reinforced PLA composites were investigated in the current study. Four different enzymes, namely lipase, lactase, pectinase, and cellulase, were used. The mechanical properties of the composites were determined by the tensile, flexural, impact tests, and dynamic mechanical analysis. According to the test results, the use of enzyme treated coir fibers affected the mechanical properties except for the flexural properties with different extents depending upon their type. The tensile strength increased with the treatments of lipase and lactase, while the treatments with pectinase and cellulase had no remarkable effect. The impact strength was improved with enzymatic treatments except for pectinase. All enzymatic treatments improved the elastic modulus below the glass transition temperature. In brief, enzymatic treatments improved the interfacial adhesion between coir fiber and PLA via the waxes and fatty acids removal and/or the increment in surface roughness.

Standardized Performance Tests and Their Impact on the Decisions Determining the Type of Rehabilitation Program

1987 ◽  
Vol 15 (4) ◽  
pp. 253-260 ◽  
Author(s):  
Anders Foldspang
Keyword(s):  
Vocational Rehabilitation ◽  
Performance Testing ◽  
Clinical Work ◽  
Early Discharge ◽  
Testing Procedure ◽  
Rehabilitation Program ◽  
Performance Tests ◽  
Test Results ◽  
Case Closure ◽  
The Impact

In the health and social sectors, many diagnostic and prognostic tests are carried out without a constant watch on (1) what influence the test results have on decisions, and (2) the impact of these decisions on every day clinical work. Consequently, it is not known whether the additional information gained, if any, justifies the expenditure necessary for resources involved in a testing procedure. In fact, the net impact of testing in every day clinical work may be negative. By carrying out a testing procedure, under the before mentioned conditions, resources would be wasted. Since the early 1970's a battery of standardized performance tests have been used at the Vocational Rehabilitation Clinic in Aarhus, Denmark. Originally, the aim of the tests was to identify and give an early discharge to those clients, that were, in any case, shown to be fit for a social pre-term pension. An early discharge of these clients would enable the Clinic to counsel a greater number of clients who were suited to vocational rehabilitation. The test period lasts two weeks, and the average stay in the Clinic amounts to about 3 months. During the years 1981 to 1983, a total of 607 clients were discharged from the Clinic. Out of the 607, 379 had been given the battery of tests. Those tested stayed 16 days longer at the clinic than the rest of the clients. A few clients got an early discharge. The associations between the test results and case closure status were weak. Furthermore, these weak associations occurred in 6 out of 51 tests. On the other hand, case closure status could be predicted on the basis of already available demographic, social, and health information on the individual clients. The conclusion is, that standardized performance testing seems to have raised the resource consumption of the clinic without any demonstrable benefit in terms of client selection. The need for continuous socio-medical and epidemiological evaluation of rehabilitation tests and procedures is stressed.

Results of pig progeny testing in Great Britain

1965 ◽  
Vol 7 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Charles Smith
Keyword(s):  
Great Britain ◽  
Test Performance ◽  
Genetic Correlations ◽  
Performance Testing ◽  
Progeny Testing ◽  
Test Results ◽  
Genetic Changes ◽  
Mild Degree ◽  
The Difference ◽  
The Impact

SUMMARYFrom 1958 to 1962 over 800 boars and 3,000 sows were progeny tested at the national pig progeny testing stations in Great Britain. Their test results for four traits (daily gain, feed efficiency, average backfat and carcass length) have been used to study the amount and effectiveness of selection and to review the use of the test facilities and their effect on pig improvement.The amount of selection on test results was studied by measuring the difference in performance of animals with sons subsequently tested and all contemporary tested animals. The selection differentials found were from 0·05 to 0·30 standard deviation units for the four traits studied which represents a rather mild degree of selection. Thus selection could have had only a small effect in improving the testing population. In fact sons of tested animals showed little advantage over their contemporaries in test performance. Parent-offspring regressions were calculated and these, in agreement with theoretical estimates, indicated that selection would be effective and would lead to genetic changes in any of the four traits studied. Genetic correlations among the four traits were also calculated and indicated genetic compatability in improving the four traits concurrently.Two proposals intended to increase the impact of testing on pig improvement are put forward. These are (1) to restrict the testing facilities to a small nucleus set of breeders who could concentrate on testing and selection and (2) to replace the progeny testing by performance testing which would allow a more intense selection and a greater rate of improvement for the same testing facilities.

The Development of a Drop Test Device for the Performance Test of the Landing Gear of an Unmanned Aircraft

2014 ◽  
Vol 513-517 ◽  
pp. 4219-4222 ◽  
Author(s):  
Sung Hoon Oh
Keyword(s):  
Airline Industry ◽  
Performance Test ◽  
Performance Testing ◽  
Landing Gear ◽  
Unmanned Aircraft ◽  
Testing Equipment ◽  
Drop Test ◽  
Test Device ◽  
Safety And Reliability ◽  
Testing Standards

An unmanned aircraft as a growth engine recently emerging in the airline industry is expanding its range from conventional military purposes into the development direction for civilian use. As such, necessary skills, components and equipment is being developed at a rapid pace and the testing equipment and techniques for checking the reliability and durability of the developed technology is also needed. But so far, performance testing standards for the newly developed product is not clear and accordingly lacks the testing equipment and techniques. In the case of landing gear, it plays an important role for the safety of the aircraft during the take-off and landing and such importance is becoming clear for an unmanned aircraft as well. However, the research and development of the drop test device for testing the performance of the landing gear is yet insufficient. As such, by developing an improved version of the drop test device from its predecessor to inspect the safety and durability of the landing gear, we hope to increase the safety and reliability of the landing gear as well as having a goal of developing a checking device for the landing gear to be developed in the future.

scholarly journals Investigation on Moisture Damage Prevention of a Spherical Hinge Structure of a Swivel Bridge

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 955
Author(s):  
Wei Guo ◽  
Xuedong Guo ◽  
Ziwen Wang ◽  
Zhun Li
Keyword(s):  
Performance Test ◽  
Unsaturated Polyester ◽  
Moisture Damage ◽  
Bending Test ◽  
Optimal Dosage ◽  
Test Results ◽  
Uniform Dispersion ◽  
Spherical Hinge ◽  
The Impact ◽  
Damage Prevention

As a key component of a swivel bridge, the spherical hinge is a steel-concrete structure, which is susceptible to moisture damage during waiting time. In this paper, spherical hinge moisture damage prevention is investigated comprehensively from two aspects of impermeable concrete and steel-concrete interface waterproof coating. Three impermeable concretes were prepared and tested by the compressive strength test, splitting tensile test, four-point bending test and the impermeability test. The test results illustrated that addition of cementitious capillary crystalline active masterbatch (CCCAM) and polypropylene fiber (PP) could improve the toughness and brittleness of concrete. The addition of CCCAM was an effective technique for improving the permeability of concrete. However, the incorporation of PP and CCCAM at the same time cannot improve the impermeability of concrete. This may be because the chaotic support structure formed by PP prevents the infiltration and uniform dispersion of CCCAM. A waterproof coating consolidation performance test was proposed to quantify the interface bond strength of waterproof coatings and assess the impact of temperature, moisture and freeze-thawing cycles on consolidation performance of waterproof coatings. The test results showed that temperature had a significant effect on the interface consolidation property of waterproof coatings and the optimal dosage of SBS modified asphalt (SBS), polyurethane (PLT) and unsaturated polyester resin (UPLS) waterproof coating is 1.18kg/m2, 0.95kg/m2 and 1.15kg/m2, respectively. Moreover, it was found that PLS waterproof coating maintained excellent properties in complex environment. This is because PLS has excellent shear strength and rubber characteristics, and it can form a hard–soft–hard transition layer between the concrete and steel, reducing the impact of environmental factors.

The impact of ultraviolet light exposure on the performance of polybenzidimazole and polyaramid fabrics: Prediction of end-of-life performance

2017 ◽  
Vol 48 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Shadi Houshyar ◽  
Rajiv Padhye ◽  
Sandip Ranjan ◽  
Steve Tew ◽  
Rajkishore Nayak
Keyword(s):  
End Of Life ◽  
Residual Strength ◽  
Ultraviolet Irradiation ◽  
Protective Clothing ◽  
Performance Test ◽  
Light Exposure ◽  
Test Results ◽  
And Performance ◽  
The Impact ◽  
Frequent Exposure

This study evaluated the deterioration in thermo-mechanical and performance properties of the polyaramid and polybenzidimazole fabric used in firefighters’ protective clothing after exposure to ultraviolet irradiation, and the effect of weathering. The performance of firefighters’ protective clothing plays an important role in protection against heat and physical threats to firefighters. However, frequent exposure to heat and ultraviolet irradiation can deteriorate performance. Test results demonstrated a 79% drop in the residual strength of polybenzidimazole/Kevlar® fabric and a 51% drop in the residual strength of polyaramid (Nomex® IIIA). The results confirmed that heat accelerates the degradation of PBI, resulting in lower performance, an important consideration for firefighters’ protective clothing. In this study, a new ‘UVPro-Tex’ sensor was developed, with the capability to record the amount of ultraviolet irradiation absorbed by the fabric. When the amount of the absorbed ultraviolet irradiation reaches a critical value, the sensor warns the wearer of the end-of-life of the garment.

Combined Cycle Performance Test Uncertainty Validation by Comparing Monte Carlo Analysis With Monovariate Perturbation Results

2006 ◽  
Author(s):  
Kerri L. Spencer ◽  
Jeffrey R. Friedman ◽  
Terry B. Sullivan
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Performance Test ◽  
Performance Testing ◽  
Monte Carlo Analysis ◽  
Combined Cycle ◽  
Plant Performance ◽  
The Monte Carlo Method ◽  
The Impact ◽  
Test Uncertainty

This paper focuses on the calculation of the test uncertainty of an ASME PTC 46 [1], overall plant performance test of a combined cycle by two separate methods. It compares the combined cycle corrected plant output and heat rate systematic uncertainty results that are generated using monovariate perturbation analysis with the Monte Carlo method. The Monte Carlo method has not been used widely in power plant performance testing applications. It offers insights into the results of the Monte Carlo analysis method, which is less intuitive than the conventional method. This study shows that utilizing two distinctly different methods of calculation of test uncertainty serves to corroborate assumptions, or to isolate flaws in one or both methods. In developing the method for calculation of test uncertainty, the authors conclude that it is prudent to validate the calculation method of choice of test uncertainty, and to consider the correlations in measurement uncertainties. Also discussed in detail are the impact of correlated uncertainty assumptions, and recommendations on their application. Correlated uncertainty has not been extensively discussed in the literature concerning specific applications in performance testing, although it should be a critical consideration in any uncertainty analysis. Details of determination of instrumentation uncertainty, measurement uncertainty of a parameter, and calculation of sensitivity factors are included in this paper.

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