Flexible Test System Research Articles

Development of a flexible phased array electromagnetic acoustic testing system with array pickups

The thermal barrier coatings (TBCs) used to protect blades of heavy-duty gas turbines is prone to debonding defects during fabrication and service. It is difficult to detect the debonding defects in the TBC system non-destructively and in situ due to the curved shape of blade and the narrow space between the blades setting in the gas turbine. In this paper, a flexible phased array electromagnetic acoustic (FPA-EMA) testing system with array pickups is developed, which is capable to drive a flexible phased array electromagnetic acoustic transducer (FPA-EMAT) to generate and receive ultrasonic wave directly in the metallic substrate of TBCs, and is potential to be applied to the inspection of debonding defects in the TBC system of gas turbine blades. A phased array excitation unit, a multi-channel signal receiving unit and a new signal post-processing algorithm are developed for the new EMA testing system to enhance the surface acoustic wave in the layered structure and to improve the low conversion efficiency of the conventional EMA testing system. In addition, a bias magnetic field coil fed with long pulse current of large amplitude is adopted to make the new EMAT thin and flexible in order to be applied in a narrow space. The interfering noise and geometric size problems brought by the multiple excitation and pickup channels are well addressed in the new system. The good performances of the developed FPA-EMA testing system were verified experimentally and show the system of good potential to be applied to NDT of practical curved structures.

A Wideband and Flexible Testing System Based on a Quasi-Coaxial Structure and Machine Learning

A Wideband and Flexible Testing System Based on a Quasi-Coaxial Structure and Machine Learning

A test bench for the assessment of flow meters accuracy for fuel consumption measurement in highly dynamic drive cycle tests

The transport sector is one of the most significant contributors in terms of NOx, particulate matter and net CO2 emission. In order to mitigate this environmental impact, severe homologation limits have been introduced by the different regional Authorities. Both pollutant emissions and CO2 production of vehicles are measured during standardized laboratory test cycles and road tests, both characterized by relatively abrupt powertrain load and fuel rate transients. This dynamic approach results in severe issues in terms of fuel flow measurement capabilities as flow meters are typically calibrated in steady fuel flow conditions. In the present activity, an experimental test bench was developed with the aim of offering a flexible and affordable test system to evaluate the performances of different flow meters in dynamic conditions. The test bench consists of a complete fuel injection system managed to reproduce an assigned cycle; by this approach the highly-dynamic engine-like fuel flow rate is replicated, offering the opportunity to compare the accuracy of the flow meter under test with both a master Coriolis-type flow meter and the nominal fuel flow time-profile. This bench allows the execution of flow meter accuracy tests in controlled operating conditions with reduced efforts with respect to conventional vehicle test benches and with a high reproducibility level.

A Highly Flexible Piezoelectric Ultrasonic Sensor for Wearable Bone Density Testing.

Driven by the loss of bone calcium, the elderly are prone to osteoporosis, and regular routine checks on bone status are necessary, which mainly rely on bone testing equipment. Therefore, wearable real-time healthcare devices have become a research hotspot. Herein, we designed a high-performance flexible ultrasonic bone testing system using axial transmission technology based on quantitative ultrasound theory. First, a new rare-earth-element-doped PMN-PZT piezoelectric ceramic was synthesized using a solid-state reaction, and characterized by X-ray diffraction and SEM. Both a high piezoelectric coefficient d33 = 525 pC/N and electromechanical coupling factors of k33 = 0.77, kt = 0.58 and kp = 0.63 were achieved in 1%La/Sm-doped 0.17 PMN-0.47 PZ-0.36 PT ceramics. Combining a flexible PDMS substrate with an ultrasonic array, a flexible hardware circuit was designed which includes a pulse excitation module, ultrasound array module, amplification module, filter module, digital-to-analog conversion module and wireless transmission module, showing high power transfer efficiency and power intensity with values of 35% and 55.4 mW/cm2, respectively. Finally, the humerus, femur and fibula were examined by the flexible device attached to the skin, and the bone condition was displayed in real time on the mobile client, which indicates the potential clinical application of this device in the field of wearable healthcare.

Reliability optimization of flexible test system based on pyro-mechanical device products production driven

The quality evaluation of aerospace pyro-mechanical device products(PDPs) is very important to the safety of aerospace engineering. Aerospace PDPs are small-lot batch, multiple batches and one-off products which rely on the analysis of ignition test with limited samples. To accommodate multiple batches and small-lot batch of aerospace PDPs, the flexible test system(FTS) switches between different batches of products by the selection of instruments and channels. The conventional test mode is driven by the completion time of batch products, which usually leads to frequent switching of instruments and channels and affects the reliability of test system. Therefore, the FTS is configured according to the completion of production missions within a certain time period in the future. This paper considers the FTS of aerospace PDPs as a phased mission system, and designs the corresponding dynamic Bayesian network(DBN) model. A test of one batch is taken as a phase of phased mission system. In order to improve efficiency and optimize reliability of the aerospace PDPs FTS, the receding horizon optimization problem is constructed. Numerical experiments show that the FTS with phased mission model can optimize the test sequence during the test process, which improves efficiency and reliability of test system.

Using improved dynamic Bayesian networks in reliability evaluation for flexible test system of aerospace pyromechanical device products

The flexible test system (FTS) for aerospace pyromechanical device products (PDPs) is an important mean to accurately assess the quality of aerospace-grade PDPs. Since PDPs are disposable products produced in small batch and multi-batch, only a limited number of samples can be tested for each batch to evaluate the quality level of whole batch of products. Therefore, the reliability of ignition FTS is concerned to ensure the reliability of limited test samples. To meet the test requirements of PDPs, the ignition FTS adopts a flexible method to adapt to the different batch types and models. Besides, the reliability of ignition FTS is related to time and product batch task, the reliability evaluation method based on traditional Bayesian network can't describe the dynamic process of product batch. Therefore, this paper proposes a dynamic Bayesian network method based on the combination of time and batch factors to overcome the limitations of product batch change, and a channel configuration optimization method is introduced to meet the reliability requirements, which provides an effective mean for evaluating the FTS reliability. Numerical experiments show that the method can accurately reflect the reliability change of FTS for aerospace PDPs.

A U-shaped microwave resonator for flexible mechanical sensors application.

A flexible mechanical deformation test system, which is a combination of the microwave and the flexible film, is proposed. The system consists of a U-shaped microwave resonator, coaxial transmission line, and PDMS flexible substrate. Microwave signals are generated from the vector network analyzer and loaded to the coaxial transmission line and then coupled to the U-shaped resonator through the coupling loop. The resonator works at the gigahertz band with the test range from 3 GHz to 40 GHz. The resonant frequency of the resonator can be adjusted by changing the shape of PDMS, and the related signals can be detected by using the S11 parameter of the microwave. The response time of the U-shaped resonator is less than 20 ms, and the sensitivity on the curved surface is 12.5 Hz/nm.

Progress on the ultrasonic testing and laser thermography techniques for NDT of tokamak plasma-facing components

ABSTRACT During manufacturing and operation, different kinds of defects, e.g., delamination or surface cracks, may be generated in the plasma-facing components (PFCs) of a Tokamak device. To ensure the safety of the PFCs, various kinds of nondestructive testing (NDT) techniques are needed for different defect and failure mode. This paper gives a review of the recently developed ultrasonic testing (UT) and laser thermography methods for inspection of the delamination and surface cracks in PFCs. For monoblock W/Cu PFCs of divertor, the bonding quality at both W-Cu and Cu-CuCrZr interfaces was qualified by using UT with a focus probe during manufacturing. A noncontact, coupling-free and flexible ultrasonic scanning testing system with use of an electromagnetic acoustic transducer and a robotic inspection manipulator was introduced then for the in-vessel inspection of delamination defect in first wall (FW). A laser infrared thermography testing method is highlighted for the on-line inspection of delamination defect in FW through the vacuum vessel window of the Tokamak reactor. Finally, a new laser spot thermography method using laser spot array source was described for the online inspection of the surface cracks in FW.

Design and Application of a Flexible Test System for Relay Communication Terminals

In order to test the functions and performance of the satellite relay communication terminal comprehensively before the satellite access network test and satellite relay communication test, a flexible automatic test system based on general hardware platform and special software was designed with electronic, communication, computer and network technologies. The testing system can provide equipment testing capability such as bit error rate, modulation signal quality and sensitivity analysis. The practical application results show that the flexible test system of relay communication terminal has the characteristics of complete function, simple operation, accurate result, stable and reliable, which is suitable for application in practical engineering.

A Novel Centralized PV Power Plant Controller for Reducing the Voltage Unbalance Factor at Transmission Level Interconnection

This paper presents a novel centralized positive and negative sequence control strategy for enhancing the unbalanced operation of electric transmission networks. The proposed control strategy is deployed as an effective ancillary service provided by a photovoltaic power plants. The excess capacity of grid-tied inverters is utilized based on a novel centralized positive and negative sequence reactive current division algorithm. The control strategy dynamically allocates the amount of reactive power compensated by each inverter in the power plant according to its active power generation level. The performance of the proposed control strategy is evaluated for a photovoltaic power plant connected to the IEEE 12-bus Flexible AC Transmission Systems test system in steady-state and transient operation. This is demonstrated through unbalanced loads and asymmetrical grid faults. The proposed control strategy effectively reduced the voltage unbalance factor within the acceptable operating limits, and enhanced the transient response at the transmission level interconnection. This is achieved in order to adhere to grid codes’ requirements and the IEC 61000-3-13 standard.

Scaled Physical Model Test on Underground Gas Storages Based on a Pneumatically Flexible Loading System

Abstract A geomechnical model test was conducted to study the stability of a salt cavern during the gas injection/recovery period. In order to simulate the internal pressure in the cavern and accurately exert the geostress, a numerical controlling pneumatically flexible loading model test system was developed. This loading system also realized the automatically loading digitalization control and visualization display. The model cavern was built using a wooden mold and was set within a latex balloon. This designation realized the injection and extraction of the gas, which simulated the variation of gas pressure in prototype engineering. During the model test, the precisely optical-based sensors were buried into the model to observe the deformation of the cavern. The deformation laws of the cavern were separately obtained at the gas stability, gas injection, and gas extraction stages. In addition, the optimal gas pressure and safe gas pressure were determined through the deformation law versus the gas pressure. Through analysis, the gas extraction and the rate of gas injection/extraction were identified to be the most important factors that threaten the stability of the salt cavern. The model test also demonstrated that the middle layer was the most at-risk section during the operation period compared to the other regions.

Development of a Microcontroller Based PV Emulator With Current Controlled DC/DC Buck Converter

Testing and validation of Photovoltaic based energy conversion systems requires Photovoltaic (PV) panels in laboratory environment. A flexible testing system, which eliminates these panels and emulates dynamic characteristics of PV sources in real time are gaining importance. This paper presents a new algorithm for emulation of PV characteristics and is implemented using DC-DC buck converter in current control mode. The algorithm tracks the point on the V-I characteristics of the PV under varying loads and corresponding current reference is generated. This reference current is used to generate gate pulses for the DC-DC converter, which acts like a constant current source to emulate the PV panel. The P-V and V-I characteristics under desired environmental condition is emulated using load resistance based algorithm for a given specifications of the PV source. In the proposed system, online variation of irradiance and temperature are incorporated as a time varying input parameters to PV emulator. The proposed algorithm has been numerically simulated using MATLAB/SIMULINK platform and is experimentally verified by means of a DC-DC buck converter (50W) prototype with AT’mega328 core controller prototype. Both simulation and hardware results are presented showing the effectiveness of the proposed system under dynamically varying loading and environmental conditions

The Research of Flexible Testing System

For the purpose of solving the problems, such as many kinds of C3I equipment signals to be test, complicated technology and technology fast updates, a test system based on flexible technology is proposed. In this system, the core technical cocept of systematize and developmental design is adopt. In this paper, the design ideas, software and hardware design and test diagnosis process are described in detail. The detection system based on flexible test achieves calling testing resources according to the different objects, interfaces conversion and signal conditioning. The system has good characteristics on flexibility, reliability, adaptability and expand [1-, which is of great significance for the equipment maintenance and support.

Flexible Intelligence Testing System (FITS)

The Flexible Intelligence Testing System (FITS) is a real time system which will be presented. FITS is a flexible testing system that can be used by academics to administer tests remotely to students via. Internet. The system will allow teachers to setup test questionnaire, scoring criteria (grades per question, etc.) and validating the results of the test. FITS is a truly production ready testing system. In a university scenario; the software can be used by the professor to setup and administer tests to multiple online students.

Technical design and principle test of active magnetic bearings for the turbine compressor of HTR-10GT

The 10MW high temperature gas-cooled test reactor coupled with gas-turbine circle (HTR-10GT) has been carried out by the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University in China since year 2002. In the power convention unit (PCU) of the HTR-10GT, the contact-free and no-lubricating active magnetic bearings (AMB) are adopted to support the vertical high-speed turbine machine shaft, because of their numerous advantages over the conventional oil mechanical bearings under the special reactor operating conditions. Based on the previous studies and small tests of the AMBs, the final engineering design of the AMBs for the HTR-10GT turbine compressor rotor has been finished recently. This paper firstly introduces the design principle and technical futures of the AMBs. Then the main structure, as well as the key dimensions and parameters of the different AMB components are illustrated in detail. Besides, the rotor dynamic analysis is conducted to provide the mathematic model for the unbalance attenuation with high performance control system design in order to smoothly pass across the first two bending critical speeds before reaching the rated speed of 15,000rpm. Furthermore, a small AMB flexible test system in compliance with the dynamic similarity principle of the helium turbine compressor rotor of the HTR-10GT, has been set up to validate the advanced control algorithms and accumulate design and operation experiences for the next full scale experiment in the near future.

HiL simulation in biomechanics: A new approach for testing total joint replacements

Instability of artificial joints is still one of the most prevalent reasons for revision surgery caused by various influencing factors. In order to investigate instability mechanisms such as dislocation under reproducible, physiologically realistic boundary conditions, a novel test approach is introduced by means of a hardware-in-the-loop (HiL) simulation involving a highly flexible mechatronic test system. In this work, the underlying concept and implementation of all required units is presented enabling comparable investigations of different total hip and knee replacements, respectively. The HiL joint simulator consists of two units: a physical setup composed of a six-axes industrial robot and a numerical multibody model running in real-time. Within the multibody model, the anatomical environment of the considered joint is represented such that the soft tissue response is accounted for during an instability event. Hence, the robot loads and moves the real implant components according to the information provided by the multibody model while transferring back the position and resisting moment recorded. Functionality of the simulator is proved by testing the underlying control principles, and verified by reproducing the dislocation process of a standard total hip replacement. HiL simulations provide a new biomechanical testing tool for analyzing different joint replacement systems with respect to their instability behavior under realistic movements and physiological load conditions.

A modular one-generation reproduction study as a flexible testing system for regulatory safety assessment

The European Union's Registration, Evaluation and Authorisation of Chemicals (REACH) legislation mandates testing and evaluation of approximately 30,000 existing substances within a short period of time, beginning with the most widely used "high production volume" (HPV) chemicals. REACH testing requirements for the roughly 3000 HPV chemicals specify three separate tests for reproductive toxicity: two developmental toxicity studies on different animal species (OECD Test Guideline 414) and a two-generation reproduction toxicity study (OECD TG 416). These studies are highly costly in both economic and animal welfare terms. OECD TG 416 is a fertility study intended to evaluate reproductive performance of animals in the P and F1-generations following repeated exposure to a test substance. It can also be used to detect adverse effects on structural and functional development. Thus, it has conventionally been preferred to the one-generation study (OECD TG 415). Recently, the Agricultural Chemical Safety Assessment (ACSA) Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) proposed that routine two-generation studies could in most cases be replaced with an "enhanced" one-generation study (Reuter et al. [1]). The flexible design proposed by HESI-ACSA allows for the addition of one or more specialised modules, if triggered (e.g. production of a second generation or the investigation of classical developmental toxicity or developmental neuro- or immunotoxicity). Significantly, however, the HESI-ACSA proposal was designed for use in the safety assessment of pesticidal, as opposed to industrial, chemicals. Thus for the purposes of REACH, a streamlined one-generation study that also examines structural development would be the most efficient means of addressing current information requirements for HPV chemicals. This study represents a flexible testing system that can be modified to meet regulatory needs in a variety of sectors.

Flexible and precise drop test system

A drop test system with flexibility in the choice of falling object has been constructed and characterized. Using the guided free fall principle, the system enables the study of impacts of a large range of objects on a wide selection of anvils, with high control of the position and orientation of the object. The latter is demonstrated with falls of a standard aluminium headform in mountaineering helmets on a kerbstone anvil, for which visual inspection with a high-speed camera confirms the desired accuracy. Impacts of a flat falling body on cylindrical polystyrene foam samples are used to derive stress–strain curves for materials of different density and for multilayer samples. In this case, the effects of striker orientation and placement on the resultant data are discussed, and the reproducibility of the data serves as an additional confirmation of the accuracy of the measurement apparatus and procedures. A check on the improvement in the level of positional and orientational striking precision achievable is obtained via an inter-laboratory comparison.

Hardware for ECU testing

During functional tests a modern and flexible test system must control the I/O interfaces of the ECU. Test cases make different demands on the connection and the operation of sensors and actuators, as well as the signalling or errors and measurement of signals. Beside the different challenges to the test system this article describes a new test hardware by Vector Informatik.

Flexible active cycle stress testing of smart power switches

Active cycle stress testing of smart power switches is conventionally performed either with current pulses of constant amplitude or with waveforms derived by switching inductive loads. A flexible test system is introduced that is capable of generating arbitrary current pulse shapes, which is verified experimentally on a typical smart power switch. It is demonstrated by a test run that pulses with different shape and amplitude but equal thermal stress derived from thermal simulation lead to comparable cycle life time.