Test Stand Research Articles

Analysis of propulsion units dedicated to test stands for aviation systems

This paper presents an analysis of selected propulsion units dedicated to test stands for unmanned aircraft systems. It focuses on engines suitable for aircraft with a maximum take-off mass up to 150 kg. The study includes an analysis of propulsion units that can be used to power systems on stationary test stands dedicated to advanced research and measurement of prototype aerospace technologies intended for use in rotorcraft. The analysis of propulsion units shows that electric units are a better choice for powering UAV rotorcraft test stands. Their main advantages include the possibility to simplify the construction of the device by eliminating gears and to mount the motor in a vertical position, simpler power supply, cooling and control systems and the lack of an exhaust system. Additional advantages are undoubtedly lower vibration generation, cheaper and easier operation as well as better comfort.

Concept and Realization of a Novel Test Method Using a Dynamic Test Stand for Detecting Persons by Sensor Systems on Autonomous Agricultural Robotics.

As an essential part for the development of autonomous agricultural robotics, the functional safety of autonomous agricultural machines is largely based on the functionality and robustness of non-contact sensor systems for human protection. This article presents a new step in the development of autonomous agricultural machine with a concept and the realization of a novel test method using a dynamic test stand on an agricultural farm in outdoor areas. With this test method, commercially available sensor systems are tested in a long-term test around the clock for 365 days a year and 24 h a day on a dynamic test stand in continuous outdoor use. A test over a longer period of time is needed to test as much as possible all occurring environmental conditions. This test is determined by the naturally occurring environmental conditions. This fact corresponds to the reality of unpredictable/determinable environmental conditions in the field and makes the test method and test stand so unique. The focus of the developed test methods is on creating own real environment detection areas (REDAs) for each sensor system, which can be used to compare and evaluate the autonomous human detection of the sensor systems for the functional safety of autonomous agricultural robots with a humanoid test target. Sensor manufacturers from industry and the automotive sector provide their sensor systems to have their sensors tested in cooperation with the TÜV.

Study and Application of Asymmetrical Disk Tools for Hard Rock Mining

In this article, the method of hard rock mining by undercutting or back incision using asymmetrical disk tools as an alternative to the milling method with the use of cutting tools was described. The results of modelling the penetration of a single asymmetric disk tool edge into an artificial and natural rock sample were presented and compared with empirical laboratory tests. The effect of stand tests for mining artificial rock samples using asymmetrical disk tools mounted on the rotating plate was presented. The tests were carried out on two unique test stands. The solution of an innovative mining head with a complex motion trajectory, using the asymmetrical disk tools, was presented. The innovative mining head especially developed at the AGH Kraków Department of Machinery Engineering and Transport for roadheaders, was presented. The results of preliminary field tests with the use of this mining head were also described.

Ground Test Stands for Testing Rotors in Insulated Conditions

Abstract The paper generally discusses Whirl Tower research stands. Whirl Tower stands are used to test, among others, rotorcrafts main rotors in hovering. The work presents an overview of similar solutions of test stand presented in the available literature and online data. Beyond these solutions the paper also contains test stands used so far at the Institute of Aviation, these solutions were prepared for testing one type of rotor (for example: only for gyroplane rotors). The article provides information about new (Whirl Tower) test stand fully designed and manufactured in Łukasiewicz Research Network ‒ Institute of Aviation (Ł-ILOT). One of the basic assumptions is that it will be a universal test stand, giving the possibility to test different types of rotors. Moreover, the article discusses the types of tests and research that can be carried out on this type of test stand, tests that are performed to ensure the safety of the rotor design.

Finding and Eliminating Noise and Interference in a Test Stand for Josephson Digital Chips

Sources of noise and interference in a test stand for Josephson digital integrated circuits have been identified and eliminated using a novel measurement technique. The digital output of the chip was fed into a spectrum analyzer while the output pattern was 1010. The DC bias was set at the boundary between correct and incorrect operation, a 50% bit error rate. Small AC noise currents on the bias made large changes in the bit error rate. This converted noise currents to amplitude modulation sidebands of the data pattern at half of the logic clock frequency, which was 625 MHz. AC currents were injected at 454 Hz to produce AM sidebands at 625 MHz ± 454 Hz. The sideband power was directly proportional to calibration tone power over the range 50 nA to 10 μA. Noise currents on the DC bias as small as 100 nA were clearly identified at 120 Hz. The largest noise currents in the test setup were found near 40 MHz. Their spectrum of evenly spaced tones indicated that the source was a switching power supply. When an idle relay controller was turned off, the noise tones immediately disappeared from the spectrum analyzer display, confirming the source of interference. This new and easy to use technique exploited bit error rate modulation to up convert AC noise currents from low frequencies to the range 625-675 MHz. The location of the noise currents was unambiguous, since only a 60 Hz noise current on the chip could produce an AM sideband at 625 MHz plus 60 Hz.

SPIDER Cs Ovens functional tests

The SPIDER experiment is operating at the ITER Neutral Beam Test Facility PRIMA since June 2018 to study the operation of a full ITER-size negative ion source. In order to increase the negative ion extracted current and reduce the co-extracted electron current, caesium is evaporated inside the source. In fact, the adsorption of Cs onto the plasma grid, i.e. the first grid of the extraction system, lowers the surface work function, enhancing the probability of surface conversion of impinging hydrogen particles into negative ions. At the SPIDER test facility, Cs will be evaporated by heating a liquid Cs reservoir in three Cs ovens located at the back-plate of the ion source. The ovens must assure a controllable and reproducible evaporation. A SPIDER Cs oven prototype was procured and tested in the CAesium Test Stand (CATS) at PRIMA site to validate the design. Following the experimental tests, few improvements were introduced in the final design of the three Cs ovens for the SPIDER source. Then, the ovens were procured in 2019 and commissioned before their installation in SPIDER in 2020. This paper reports the functional tests of the SPIDER Cs ovens and of their embedded diagnostics. These tests were carried out at CATS, with the aim of characterizing the three ovens, in order to validate them for their use in SPIDER in the experimental campaign with caesium evaporation planned for the end of 2020. The ovens were successfully tested and characterized in terms of evaporation rate for different oven temperatures. Moreover, the three ovens show a good reproducibility and reliability.

Super-Cooled Large Droplet Experimental Reproduction, Ice Shape Modeling, and Scaling Method Assessment

Super-cooled large droplets (SLDs) present a unique experimental challenge for conventional horizontal spray icing wind tunnels due to gravity effects on the droplets and coalescence between the particles. Limited ice accretion shapes in this regime exist, making the verification of modeling tools and the validation of the applicability of scaling methods difficult. Furthermore, SLD accretions often occur in nature in a bimodal icing cloud, providing an additional facility challenge related to the reproduction of such clouds. The objective of this research effort is to expand the available SLD dataset to assess the capability of an existent ice accretion tool (LEWICE 2D) to predict such ice shapes. The effort also attempts to further verify the applicability of ice shape scaling methods in the SLD regime. Finally, bimodal SLD cloud reproduction and ice shape prediction is investigated. The Adverse Environment Rotor Test Stand (AERTS) at Penn State was assessed as an alternative facility to icing wind tunnels for ice accretion testing in the SLD regime. Laser diffraction measurement data analysis demonstrated that the icing nozzles used in the facility can produce an SLD within of requested values. Techniques to measure liquid water content (LWC) in the facility are also presented. LWC was controllable within . LEWICE ice shapes predicted were obtained using legacy empirical heat transfer models as well as an updated empirical heat transfer function developed at Penn State. When comparing modeling results to experimental shapes from the literature and the AERTS, LEWICE with the updated heat transfer function provided stagnation thicknesses within 5.6% of experimental values and horn protrusion within 16%. The modified Ruff scaling ice shape method was effective in the SLD regime, providing a mean deviations of 2.5% between reference and scaled ice shape characteristics. Finally, characteristics of a bimodal ice shapes were predicted by LEWICE. When comparing modeling results to experimental shapes, LEWICE with the updated heat transfer function provided predictions within 10.3% of the experimental stagnation thickness measured. It also provided horn angles with discrepancies of less than 12%. Icing limits of a bimodal icing cloud were observed to be that of a single mode SLD cloud of the same MVD, with an overall deviation of when comparing the experimental database to LEWICE.

Developments on two lithium vapor-box linear test-stand experiments

Abstract The lithium vapor-box divertor is a possible fusion power exhaust solution. It uses condensation pumping to create a gradient of vapor density in a divertor slot; this should allow a stable detachment front without active feedback. As initial explorations of the concept, two test stands which take the form of three connected cylindrical stainless steel boxes are being developed: one without plasma at PPPL, to test models of lithium evaporation and flow; and one for the linear plasma device Magnum-PSI (at DIFFER in Eindhoven, The Netherlands) to test the ability of a lithium vapor cloud to induce volumetric detachment and redistribute the plasma power. The first experiment uses boxes with diameters of 6 cm, joined by apertures with diameters of 2.2 cm. Up to 1 g of Li is placed in one box, which is heated to up to 600 ° C . The Li evaporates, then flows to and condenses in the two other, cooler boxes over several minutes. The quantity of Li transported is assessed by weighing the boxes before and after the heating cycle, and is compared to the quantity predicted to flow for the box at its measured temperature using a Direct Simulation Monte Carlo code, SPARTA. With good experimental conditions, the two values agree to within 15%. The experiment on Magnum-PSI is in the conceptual design stage. The design is assessed by simulations using the code B2.5-Eunomia. They show that when the H + plasma beam, with n e = 4 × 10 20 m −3 , T e = 1.5 eV , and r = 1 cm , is passed through a 16 cm long, 12 Pa, 625 ° C Li vapor cloud, the plasma heat flux and pressure on the target are significantly reduced compared to the case without Li. With the Li present, the plasma is cooled by excitation of Li neutrals followed by radiation until it volumetrically recombines, lowering the heat flux from 3.7 MW m−2 to 0.13 MW m−2, and the pressure is reduced by 93%, largely by collisions of H + with Li 0 .

A comparative assessment of reliability indicators and parameters of the bearings using different estimation methods

The paper depicts the method of statistical processing of experimental results, obtained by testing bearings on the test stands, using the maximum likelihood estimators and/or Best Linear Invariant Estimator. To verify statistical assumptions regarding parameters and reliability indicators of bearings, as well as, to determine confidence intervals, the article contains two original algorithms that allow obtaining values of some specific random variables by Monte Carlo numerical simulation. The statistical inferences are made through these values. The paper also, contains two case studies using data from failures and time truncated tests of bearings.

Test Stand for Experimental Crash Tests at Low Speeds

The article presents a test stand with a control system and data acquisition for experimental crash tests at low speed. Crash tests are carried out at a low speed of the wheelchair and seat. Measurement and equipment allows to record and determine the displacements of individual parts of the body of the tested object. During the test, a constant speed of 20 km/h was kept. The paper presents test results of volunteers taking into account gender. The results of the conducted research showed that the trajectory of the head movement of female volunteers coincides with that of the male head. The result of these studies is an important argument for the construction of an anthropometric dummy intended for low speed crash tests, as the results can be averaged over the entire population without gender division.

Identifying a cut-off point for Timed Up and Go Test and 30-second Chair Stand Test in dual-task condition: Effects of cognitive status

Identifying a cut-off point for Timed Up and Go Test and 30-second Chair Stand Test in dual-task condition: Effects of cognitive status

Measuring the peeling strength between polymers (low density polyethylene, ethylene propylene diene monomer (EPDM) rubber) and brass and evaluating the effect of thermal and chemical oxidation on the metal

This research aims to study the effect of adhesion of different polymers to brass, where two types of polymers were used, represented by Ethylene Propylene Diene Monomer (EPDM) rubber and the second type of Low Density Polyethylene (LDPE) polymers. The surface of brass was treated by thermal oxidation and chemical oxidation. The chemical oxidation is carried out using concentrated hydrochloric acid for a period ranging between (10–15 min) and etching occurs. Thermal oxidation samples are made of brass at different temperatures (100.200.300° C), which is evidenced by thermal oxidation at a low temperature (100° C) the occurrence of a thin layer of cuo and this layer increases with increasing temperatures (200, 300° C) This layer cant only be seen with the naked eye by examining the EDS, and this layer affects the adhesion process The adhesion of polymers takes place in two ways, either the kneading method - then pressing by thermal pressing of specific types of polymers represented by the rubber or by the method of melting the polymer on the surface of the metal - then pressing through a heat press, and in both cases a specially designed mold is used for this process. The adhesion strength is measured by skinning the brass after processing it through the (Motorized Test Stand ESM) device, which measures the force in distance per second in units of kilo Newton, and the best adhesion efficiency is achieved.

Methodology for building the optimal test bench of software and hardware complexes of control systems

The paper considers the issue of creating unified approaches to building test stands for software and hardware control systems. A universal architecture of the test bench is proposed and the author’s method of constructing optimal test stands, obtained as a result of research in the field of complex automation of the test process, is described. The algorithm of directed search for the best test stand configuration is considered by example and the results of the implementation of the proposed method are demonstrated.

OKBM Afrikantov Research and Testing Complex: From Creation to the Present Day

Testing and experimental substantiation are a significant and integral part at all phases of the life cycle of reactor equipment. The Research and Testing Complex (RTC) operates at OKBM Afrikantov to ensure that these tasks are successfully fulfilled. The RTC provides the opportunity of performing a wide range of research and testing during the creation of reactor installations as well as the development of the main and auxiliary equipment for the nuclear energy industry. The most significant work performed on the experimental base at OKBM in the last 15–20 years reduces to neutronics and thermotechnical studies of cores and FA, testing equipment for naval and civilian ship reactor installations and NPP, experimental substantiation of systems and study of processes occurring in them and the elements of the equipment in nuclear installations, and the study of the corrosion and strength properties of materials. Work on modernization of currently operating and creation of new test stands is ongoing at the RTC.

System analysis and processing of parameters of the test bench

The paper deals with the analysis of complex technical objects – test stands of control systems. A method is proposed for evaluating the effectiveness of the test bench based on the parameters obtained using the “standard” and “automated” test stand model. The objective function for calculating the efficiency of test benches based on their parameters and determining the numerical efficiency coefficient of the testing position relative to the typical one is given. The composition of the software for implementing the proposed method is shown.

Use of Simulator Equipment for the Development and Testing of Vessel Control Systems

Abstract One of the ways to reduce human influence on the control process is the development of automated and automatic control systems. Modern control systems are quite complex and require preliminary ground testing. The article considers the issues of creating Imitation Modelling Stand for such control system synthesis and testing. For this reason, a Control System Model was integrated into the local computer network of the navigation simulator NTPRO 5000. The authors of the paper developed and tested software for information exchange between the navigation simulator and the Control System Model. The authors also developed a functional module of collision avoidance with many targets for testing in a closed loop system with virtual training objects. The results showed that the developed Imitation Modelling Stand allowed developing and testing functional modules of the control systems. In comparison with the found analogues, it is easy to include in a closed simulation cycle various models of command devices, actuators, control objects, objects of training scene, weather conditions; it is universal both for solving problems of manual control and for developing and testing automatic and automated control systems; it is not highly specialised and is created at minimal costs.

Modular Test Stand for Fatigue Testing of Aeronautical Structures – Verification of Assumptions

Abstract The Modular Test Stand was developed and manufactured to decrease the cost of fatigue testing and reduce the time of its completion as well as to enable testing specimens under more complex load conditions. The stand consists of three connected sections, similar to a wing box, all being loaded in the same way. Thanks to that, several specimens can be tested simultaneously. This configuration requires that stress and strain distribution should be reasonably uniform, as assumed in the design stage. The structure can be loaded with bending or torsion. A whole section, selected structural node or a specimen mounted in the structure as well as a repair or a sensor can be a test object. Two stands, one for bending and one for torsion were prepared. This paper presents the verification of the assumed strain and stress distributions on the skin panels. The measurements were performed with the use of Digital Image Correlation (DIC) as well as strain gauges. DIC measurements were performed on one skin panel of the central section. Five strain gauge rosettes were installed on both panels of the one section. In addition, one rosette was applied to one skin panel in each of two other sections. Measurements were performed on the stand for torsion as well as on the stand for bending. The results of DIC analysis and strain gauge measurement during torsion show uniform shearing strain distributions on the panels. During bending, on the tensioned side, the strains obtained indicate quite uniform strain distributions. On the compressed side, local buckling of the skin panels results in high strain gradients. Strain levels obtained with the use of a DIC analysis and strain gauge measurements were similar. Moreover, horizontal displacements of markers in the spar axis during bending was determined based on a series of photographic. The deflection line obtained in this way has a shape similar to arc, which is characteristic of the constant bending moment. The stand was tested with torsional and bending loads in order to verify the design assumptions. The results of strain distributions on the skin panels with the use of DIC and strain gauges as well as the deflection line of the spar axis indicate that the Modular Test Stand performs as assumed and can be used for tests.

Визначення витратних характеристик ресивера за допомогою комп’ютерного моделювання

The problem of implementing the detonation mode of fuel combustion in thermal propulsion systems has been widely studied last decade. There are many works on fundamental and applied research on pulsating detonation. Solid propellant detonation engines can develop significant forces for a short time at low structural masses, and therefore they are ideal for auxiliary systems for the removal of separated rocket parts. In addition, detonation processes can be used to create control forces for correcting the trajectory of aircraft. All these facts determine the relevance of the area of work. For studying detonation installations, it is necessary to create test stands, but the design of test installations is an urgent and complex optimization problem. It is advisable to solve this problem with the help of computer simulation. In the existing experimental methods, for designing, it is necessary to determine in advance the geometric parameters of receivers and pipelines that provide the necessary gas consumption for firing tests of detonation rocket engines. The work is devoted to the development of a method for determining the flow characteristics of a receiver with a pipeline of complex configuration based on the constructed model of the stand. Based on the initial data, a computer simulation of the air leakage process from the receiver was carried out, for which the Solid Works software package was used. The places of pressure drop, maximum flow rate, and air mass flow are determined. The low value of the flow rate factor is due to the complex configuration of the pipeline with numerous bends and two bellows. Comparison of calculation results with experimental data was held. The difference between the experimental and calculated values does not exceed 3.6%. The obtained information is used to select the required value of the oxidizer excess coefficient during firing tests of detonation rocket engine models. Keywords: flow rate, gas leakage, receiver, model.

Heat and Harmonics: Solutions to Concerns in Air-Cooled Medium-Voltage Adjustable-Speed Drives

Scholarly publications exist on several aspects of adjustable-speed drives (ASDs). Their application considerations, benefits, specifications, and operation are well understood. Medium-voltage (MV) drives have been applied not only to upstream, midstream, and downstream industries of the oil and gas value chain but also in other industries such as pulp and paper, cement, water and waste water, power generation, and test stands. This has been possible because of reliable highcapacity power semiconductor devices. Heat loss is a major contributor to the lifecycle cost of an installation of MV drives. This is not understood initially but becomes significant when assessed over a 25-year life span. Air-cooled drives are specified at large horsepower ratings or in places with high or low ambient temperatures without fully understanding the long-term impact to reliability, safety, and running costs. On another note, line-side harmonics is also of concern not only to the power delivery apparatus of an operator?s plant but also to the utility providers. IEEE Standard 519-1992, which was revised in 2014, is often specified for MV drives, but the application and understanding of the standard are inconsistent among industry participants. This article addresses the foregoing two issues. First, it describes conventional and nonconventional methods for managing heat that the industry has developed and will cover application considerations when specifying, evaluating, procuring, and installing those solutions. The final part of the article reviews IEEE Standard 519-2014 and how it is applied in the context of an MV drive. Further, the article briefly touches online-side harmonic mitigation techniques that are employed and how to specify them to best avoid issues. Guideline for practicing engineers to familiarize themselves with the heat and harmonic issues of MV drives and how to tackle them successfully are also covered in this article.

High-Power Dielectric Diode Studies at Sandia National Laboratory

Our research was mainly concentrated on the physics of semiconductor diodes and especially on measuring the reverse recovery times and currents. In addition, we explored the effect of the reverse bias pulses on a diode still under reverse recovery times. Therefore, we tested the diode cartridges only up to 40% of the scale of that of LANL. We utilized our Component Test Stand (CTS-I) facility modified to power two diode cartridges connected in parallel to a common load (CTS-II). We varied the charge voltage and interpulse separations between the two diode cartridges. In this article, we will describe the modifications of CTS leading to CTS-II and present and analyze the obtained results.