Test Rig Research Articles

Resonant peak reduction of a rotor system based on gradually variable stiffness of supports with shape memory alloy springs

A novel method for reducing the resonant peak of a flexible rotor at critical speeds based on control of the gradual variable stiffness of supports (GVSS) using shape memory alloy (SMA) springs is presented in this paper. The resonance peaks of a rotor structure can be attenuated through the design of GVSS law. Firstly, the impact of GVSS on the rotor's critical speeds was analyzed, and the mechanical mechanism of vibration reduction based on GVSS was identified. Secondly, a rotor system with a single critical speed was used for simulation analysis and it was founded that the starting time to change support stiffness and the change rate were two critical factors that affect vibration reduction. Then, a further simulation was undertaken on a test rig designed with dynamic similarity of an aeroengine rotor having multiple supports and multiple critical speeds. The range of the variable stiffness with SMA springs’ supports and the control strategy of GVSS were investigated. Afterwards, the test rig was manufactured and assembled for testing and validation. To achieve rapid temperature changes for variation of the support stiffness, an innovative design utilizing the carbon fiber heating tubes and the liquid nitrogen sprays for heating and cooling of shape memory alloy springs was carried out. The test results indicate that using gradually variable stiffness of supports with SMA Springs can effectively reduce the multiple resonance peaks of a rotor, with a maximum suppression rate of 52.3 %. This verifies the feasibility of the method. It also indicates the potential for further engineering applications.

Study of the self-repairing performance of magnesium silicate hydroxide containing-oil enhanced by solid surface of oleophobic modification

The study aims to improve the self-repairing performance of magnesium silicate hydroxide (MSH)-containing oil. The self-repair behavior of the MSH-containing oil on different wetting surfaces under limited and fully-flooded oil supply is observed using an optical interference test rig. The results indicate that MSH nanoparticles neither prevent nor accelerate starvation. However, controlled by surface tension, oleophobic surfaces facilitate the MSH aggregation in oil and promote its redistribution in the lubricant, thereby enhancing the self-repair efficiency of MSH. This study expands the understanding of the self-repair behavior of MSH on surfaces with different wetting properties and provides important references for the design and application of novel bearing.

A Simulation Approach for Analysis of the Regenerative Potential of High-Speed Train Suspensions

This study primarily investigates the adaptability and performance of hydraulic–electric regenerative dampers for high-speed trains by substituting conventional primary dampers with hydraulic–electric regenerative dampers. The primary objectives are to develop a detailed model of primary suspension regenerative damper (PSRD) energy conversion that incorporates factors such as oil pressure loss, motor efficiency, and overall system efficiency, and to perform a comprehensive comparative analysis of vibration responses, wheel wear, comfort indices, and power generation using an integrated MATLAB and SIMPACK co-simulation platform. The results reveal that at an operational speed of 350 km/h, the dynamic responses of the carbody, bogie, wheelset, and dampers equipped with the proposed PSRD systems closely align with those of conventional primary vertical damper systems. The detailed PSRDs’ hydraulic–mechanical–electrical model effectively captures the subtleties of oil pressure fluctuations and their impacts. The wear distribution and magnitude across the vehicle remain consistent during acceleration, constant, and deceleration speeds, ensuring uniform wear characteristics. Under real-world railway operational conditions, the ride comfort metrics of vehicles fitted with regenerative dampers are comparable to those with conventional primary vertical dampers. Furthermore, each regenerative damper can generate up to 21.72 W of electrical power, achieving a generation efficiency of 45.28%. Finally, a test rig was designed and fabricated to validate the primary suspension regenerative damper (PSRD) model, showing good agreement between predicted and actual damping force and power regeneration, with results indicating a peak damping force of 12.5 kN and approximately 230 W of regenerated power. This research provides a theoretical foundation and experimental validation for implementing power regeneration mechanisms in railway transportation, demonstrating that the hydraulic–mechanical–electrical PSRD model can fulfil the performance criteria of conventional dampers while offering substantial energy harvesting capabilities. This advancement not only enhances energy efficiency but also contributes to the sustainable development of high-speed rail systems.

Difference thresholds for primary and secondary ride of a vehicle on a 4-poster test rig

Not only is it important to know how large the overall change in vibration should be for occupants to perceive an improvement in comfort, but also how large this change should be in specific frequency bands. Relative difference thresholds (RDT) of primary (0.5–4 Hz) and secondary (9–80 Hz) ride are estimated for 14 automotive engineers seated in a vehicle on a 4-poster test rig over two roads. Resulting stimuli differed in magnitude and spectral shape. The median RDTs estimated for primary and secondary ride were 16.68% and 13.82% on the smooth road, and 9.50% and 24.67% over the rough road. Statistically significant differences were found in the medians of the RDTs between (1) primary and secondary ride on the two roads and (2) the two roads for changes in the primary and secondary ride, suggesting that Weber’s law does not hold.

Experimental and numerical characterization of screw elements used in twin-screw extrusion

Hot melt extrusion by a co-rotating twin screw extruder is an important process in the pharmaceutical industry. Especially for quality by design aspects, a comprehensive process understanding is indispensable. The performance of conveying elements was determined as critical process parameter, and therefore an experimental and numerical framework was developed to analyze and compare variations. A test rig capable of measuring volume flow, pressure and torque with high accuracy and precision was designed and built. The 3D simulation was performed using computational fluid dynamics (CFD). A stationary model with impulse transmission and an apparent motion of the screws was applied. The experimental data were fitted to the model of Pawlowski, and parameters for the pressure (A1, A2) and power characteristics (B1, B2) were determined. Good agreement between experimental data and the model was observed. The simulation was significantly faster compared to common methods, and the results were consistent with the literature. Systematic investigations of a native and worn screw were performed with CFD resulting in a transport capacity increase and a pressure build up decrease for all tested screw elements. An experimental and simulation setup was generated to assess the performance of co-rotating twin screw elements. The experiments provided high-quality data, and the simulations exhibited high flexibility with low computational effort.

An experimental investigation of an energy regeneration suspension

Energy absorbed from road bumps in traditional suspensions is dissipated as heat. An energy regeneration suspension (ERS) has the capability to capture and store this energy in batteries. It has the potential to be used in several categories of vehicles, encompassing cars, trucks, buses, and even trains. ERS technology shows significant promise in enhancing the fuel efficiency and environmental sustainability of vehicles. In this paper, the design of an ERS that converts kinetic energy into electrical energy is presented. The primary objective is to identify key design parameters that result in high magnetic intensity levels in the air gap of the ERS model. Optimizing these parameters is essential to maximize the advantages of ERS while minimizing any drawbacks. The study investigates the impact of different magnetic permeability materials in the ERS model using ANSYS software. A test rig is established based on the analysis results to assess the energy regeneration efficiency of the ERS model under various excitations. Experimental results demonstrate that ERS models with higher permeability inner sleeves exhibit superior energy regeneration efficiency.

Precise pose control of shaft boring machine considering the characteristic of stratum

The shaft boring machine (SBM) is innovatively applied to shaft engineering with depth and large diameter for the advantages of efficiency, adaptability, and safety. The manual and rough pose control of SBM blocks the improvement of engineering quality and efficiency. This article presents a precise pose control method for SBM considering the characteristics of strata. The kinematic model of SBM and the mechanical-hydraulic-rock coupled dynamic model of grippers actuator are established considering the characteristics of different surrounding rock, respectively. A test rig is established to validate these models. The stratum-adapted double-layer controller is designed for the pose control from the practical aspects, including the deviation and inclination of the SBM center. The upper layer devotes to the kinematic planning between pose and displacement of grippers. The linear active disturbance rejection control (LADRC) method is used to control each gripper in the lower layer. The compensation control strategy is proposed to improve the reliability of the system under the different strata conditions. The stratum-adapted property is validated with the simulation of different surrounding rock characteristics. The control test under hard rock condition is performed with the test rig. The results indicate that the displacement control error of the single gripper cylinder is less than 1.8%, and the corresponding control error of deviation and inclination angle of the SBM center is less than 2.1% and 2.3% respectively. The proposed method can cover the precise pose control under different strata conditions, and it can be applied in the shaft infrastructure construction practically.

High-temperature erosion behavior of Al2O3 reinforced Inconel625 high velocity oxy-fuel sprayed and direct-aged composite coatings

In this study, Inconel625+30%Al2O3 (IN30AL) blended powders were sprayed on a commercially used boiler steel ASTM SA210 GrA1 using high-velocity oxy-fuel approach (HVOF). The microstructure, mechanical properties and elevated temperature erosion behavior of post-processed coatings and as-sprayed IN30ALcoatings were investigated. The elevated temperature erosion studies on IN30AL coatings both as-sprayed and post-processed were investigated at 900 °C temperature at two impact angles 30° and 90° using standard high temperature erosion test rig. Phase composition, interface of substrate/coating, and morphologies of eroded coatings were examined using x-ray diffraction, x-ray maps, scanning electron microscope, & energy dispersive spectrometer techniques. Compared with the as-sprayed IN30AL coatings, the heat-treated coatings have refined microstructure, better mechanical properties which improve the elevated temperature erosion resistance of IN30ALcoatings.

Manufacturing trials of PFCs with low thermal conductivity features for limiters

In future demonstration fusion power plants, plasma facing components will face high steady state and ultra-high transient heat loads from the plasma. Introducing low thermal conductivity features to the component can reduce the peak temperatures seen by the coolant pipe during transient loads, but at the trade-off of a loss of steady-state performance. Producing low-conductivity tungsten by additive methods has been investigated elsewhere, so this trial investigates production through subtractive means i.e., conventional milling. This method preserves the original temperature limits and majority of the microstructure and is much higher Technology Readiness Level (TRL) so requires less development to reach series manufacture. In this trial, diamond drilling produced holes in monoblocks down to 0.6 mm and ligaments down to 0.7 mm, showing that this method is capable of producing small features in a controlled way. With the geometric design of lattice used in this trial, these samples achieved thermal conductivity reductions of 15% to 40%. One monoblock assembly was tested up to 1100 °C for 500 cycles in the Heating by Induction to Verify Extremes (HIVE) High Heat Flux test rig and showed no signs of ligament cracking or thermal degradation. Electromagnetic modelling has been validated against the experimental results, so future designs can be accurately modelled ahead of testing in HIVE.

Effect of the Mineralogical Composition of Sandstones on the Wear of Mining Machinery Components

The paper provides and comments on the results of studies of the effect of sandstone-based abrasives and quartz sand alone on the wear of martensitic surfaces of wear-resistant steels. The wear process was examined on a ring-on-ring test rig seeking to determine the mass decrement parameter which characterised wear. In addition, SEM microscopy, optical profilometry and XRF analysis were used to analyse the abrasives used and damaged surfaces. The tests were conducted for three sandstone varieties, Carboniferous, Permian, and Cretaceous, and they made it possible to determine that the most intense process of deterioration of wear-resistant steels took place in the presence of quartz sand grain, while less intense wear was observed in the case of sandstone-based abrasives. The mass decrement values established in the presence of the sandstones in question did not differ significantly between individual sandstone varieties. Based on a surface damage analysis, the basic damage mechanism was found to be micro-scratching; however, with regard to the sandstones examined, it was also determined that individual grains could be pressed into surface irregularities and that films of soft hematite cement developed in the Permian sandstone and that inclusions of carbonaceous matter were formed in the Carboniferous sandstone. With reference to the wear process observations, a wear model was described for the surface of the steels examined in the presence of sandstone-based abrasives. This model presents the possibility of capturing wear products by unstable binder layers and changing the form of wear from three-body to two-body.

AERODYNAMIC IMPACT OF SECONDARY AIR INJECTION FLOWRATES ON THE MAIN ANNULUS FLOW FIELD FOR A TRANSONIC HIGH-PRESSURE TURBINE STAGE

Abstract In this study, the influence of secondary air blowing on the main annulus flow field of a transonic high-pressure turbine (HPT) was investigated experimentally and numerically. The experimental setup was a single-stage, unshrouded turbine with a blading consistent with modern HPTs. The entire testing campaign was conducted in a full annular, rotating, continuous turbine test rig at the Japan Aerospace Exploration Agency (JAXA), which realized the most faithful matching unrivalled of both the primary and secondary stream similarity parameters to reality. An elaborate secondary air system implemented in the hardware enabled it to mimic all the dominant coolant/purge streams representative of advanced hot sections: the full coverage film-cooling on stator and rotor airfoils, disk wheelspace purge air blown forward and aft of the rotor, and coolant injection through the over-tip casing. Detailed three-dimensional flow field measurements for various secondary air flowrates were performed by traversing a pneumatic thermometric combination probe downstream of the rotor. A complete set of numerical simulations was run concurrently with the testing to determine how well they captured the flow physics, particularly the interaction of the ejected secondary streams with the primary flow. The JAXA in-house code, UPACS, and its best practice settings, based on past verification and validation efforts, were employed and not intentionally tuned to better fit the data.

Adaptive mode decomposition method based on fault feature orientation and its application to compound fault diagnosis of planetary gearboxes

Abstract Planetary gearboxes often experience multiple component failures during service, which can accelerate the degradation and failure of industrial equipment. Accurate separation and identification of multiple faults is an important means of ensuring the safe and stable operation of equipment. However, different faults can interact with each other, along with the influence of background noise, making it challenging to accurately extract faults with relatively weak energy among multiple faults. This difficulty leads to the problems of potential misdiagnosis and underdiagnosis. To address this issue, an adaptive mode decomposition method based on fault feature orientation (AMD-FF) is proposed in this paper. Initially, a fault impact indicator (FII) is constructed based on period-weighted kurtosis of envelope spectral and correlated combination negentropy to effectively characterize the impulsiveness and periodicity of fault features. Furthermore, with the objective of maximizing the FII, an adaptive decomposition of the original signal is designed based on blind convolution theory using a finite-impulse response filter group. Subsequently, a variable weight particle swarm optimization is employed to adaptively optimize the key decomposition parameters. Finally, the data of industrial-grade planetary gear transmission test rig are collected to validate the proposed method for compound fault diagnosis of planetary gearboxes. The results indicate that the AFMD-FF can effectively separate and extract compound faults in planetary gearboxes, demonstrating superior fault separation and diagnostic performance compared to the fault mode decomposition (FMD) and adaptive FMD. This method offers a novel approach to diagnosing compound faults in rotating equipment in industrial scenarios.

Exoland Simulator, a Laboratory Device for Reflectance Spectral Analyses of Planetary Soil Analogs: Design and Simulation

In planetary science, visible (Vis) and near-infrared (NIR) reflectance spectra allow deciphering the chemical/mineralogical composition of celestial bodies’ surfaces by comparison between remotely acquired data and laboratory references. This paper presents the design of an automated test rig named Exoland Simulator equipped with two reflectance spectrometers covering the 0.38–2.2 µm range. It is designed to collect data of natural/synthetic rocks and minerals prepared in the laboratory that simulate the composition of planetary surfaces. The structure of the test rig is conceived as a Cartesian robot to automatize the acquisition. The test rig is also tested by simulating some project trajectories, and results are presented in terms of its ability to reproduce the programmed trajectories. Furthermore, preliminary spectral data are shown to demonstrate how the soil analogs’ spectra could allow an accurate remote identification of materials, enabling the creation of libraries to study the effect of multiple chemical–physical component variations on individual spectral bands. Despite the primary scope of Exoland, it can be advantageously used also for tribological purposes, to correlate the wear behavior of soils and materials with their composition by also analyzing the wear scars.

Two-Photon Planar Laser-Induced Fluorescence Of Near-Wall CO During The Interaction Between A Flame And A Cooling Air Film

Reducing the anthropogenic pollutant emissions is a major concern in the aeronautical community. Implementing high-power density core engines made of lighter materials would undoubtedly increase the thermal efficiency and reduce CO 2 emissions. Nevertheless, near-wall combustion processes will become significant, raising concerns regarding thermal management. As a result, walls in aero-engine combustors are commonly cooled, but it also introduces more complex physical phenomena associated to pollutant formation during flame-cooling air interaction (FCAI). This experimental study aims at elucidating the role of the cooling air film on CO emissions during FCAI. The experiments are conducted in an atmospheric pressure and optically-accessible lab-scale combustion test rig dedicated to near-wall combustion. It generates a lean premixed turbulent methane/air V-shaped flame, with one branch of the flame that interacts with an oil-cooled stainless-steel wall. A splash-cooling plate system enables to generate a momentum-controlled parietal cooling air film. The novelty of this study is to develop and implement planar laser-induced fluorescence of the CO molecule (CO-PLIF), complemented by planar laser-induced fluorescence of the OH radical (OH-PLIF) as well as global CO emissions in the exhaust gases. Results show that the excitation of the Hopfield-Birge system enables to detect the AN ngström bands and the third positive system. However, significant interferences with C 2 and CN emissions are highlighted, being more pronounced in rich combustion conditions, and originating from the incomplete fuel oxidation as well as the high energy density of the two-photon excitation process. A broadband collection strategy of the AN ngström bands is selected, since these interferences are limited in lean combustion regimes. The analysis of the flame dynamics indicates that the increase of the cooling air film momentum shifts the reactive flow away from the wall, but also controls the flame wrinkling through modified aerodynamics. As a result, the flame is not influenced anymore by thermal quenching processes, and can effectively burn further away from the wall. Global emission measurements indicate an increase in CO when the cooling air film momentum increases. While thermal quenching favors a faster oxidation downstream of the flame, the establishment of the cooling air film leads to a longer flame with more production areas. CO-PLIF imaging concurs this phenomenon, with a CO distribution all along the wall when the cooling air film is well established.

An optimized dynamic model improved deep discriminative transfer learning network for fault detection in rotation vector reducers

In recent years, recognized fault types using artificial intelligence (AI) models has gradually become one of the mainstream directions in the field of mechanical fault diagnosis. However, it is very difficult to obtain relatively complete fault samples, which limits the application of AI models for complex mechanical systems, such as rotation vector (RV) reducers. To address this issue, physical model-based fault sample generation methods attracted many attentions but still an open problem: the difference in fault samples between numerical simulation and measurement of a physical system needs to be well decreased. Therefore, this article proposes an improved deep discriminative transfer learning network (IDDTLN) for RV reducer fault diagnosis. The presented network is driven by an optimized dynamic model. Firstly, the measurement normal signal and whale optimization algorithm (WOA) are utilized to update the dynamic model parameters of the RV reducer. Secondly, the updated numerical model is employed to calculate simulation fault samples. Finally, simulation samples and unlabeled measurement fault samples are used to train IDDTLN. The trained IDDTLN can accurately identify the unknow measurement fault samples. The data obtained from RV reducer test rigs are utilized to explore the feasibility of the proposed method, and the classification accuracies reach 99.8 %.

The effect of path curvature on the stability of reversing truck–semitrailer in the presence of feedback delay

Stability analysis of the low-speed reverse motion along clothoid curve is presented for the truck–semitrailer combination. The single-track kinematic model supplemented with the steering system and the lower-level controller is applied. A higher-level controller is designed to stabilise the reverse motion of the vehicle. Linear state feedback with time delay is used with feedforward term to force the vehicle to the desired path. The linear stability analysis is done by semi-discretization and D-subdivision methods to determine the optimal control gain setup. The effects of path curvature and time delay on the stability are investigated and verified via numerical simulations. Results are validated via experiments using a small-scale test rig.

Research on the strain gauge mounting scheme of track wheel force measurement system based on high-speed wheel/rail relationship test rig

PurposeThis paper aims to analyze the stress and strain distribution on the track wheel web surface and study the optimal strain gauge location for force measurement system of the track wheel.Design/methodology/approachFinite element method was employed to analyze the stress and strain distribution on the track wheel web surface under varying wheel-rail forces. Locations with minimal coupling interference between vertical and lateral forces were identified as suitable for strain gauge installation.FindingsThe results show that due to the track wheel web’s unique curved shape and wheel-rail force loading mechanism, both tensile and compressive states exit on the surface of the web. When vertical force is applied, Mises stress and strain are relatively high near the inner radius of 710 mm and the outer radius of 1110 mm of the web. Under lateral force, high Mises stress and strain are observed near the radius of 670 mm on the inner and outer sides of the web. As the wheel-rail force application point shifts laterally toward the outer side, the Mises stress and strain near the inner radius of 710 mm of the web gradually decrease under vertical force while gradually increasing near the outer radius of 1110 mm of the web. Under lateral force, the Mises stress and strain on the surface of the web remain relatively unchanged regardless of the wheel-rail force application point. Based on the analysis of stress and strain on the surface of the web under different wheel-rail forces, the inner radius of 870 mm is recommended as the optimal mounting location of strain gauges for measuring vertical force, while the inner radius of 1143 mm is suitable for measuring lateral force.Originality/valueThe research findings provide valuable insights for determining optimal strain gauge locations and designing an effective track wheel force measurement system.

Investigation of Crystallization Fouling on Column Internals using a Screening Test Rig

Investigation of Crystallization Fouling on Column Internals using a Screening Test Rig

Analysis of braking performance and heat dissipation characteristics of multi-disc magnetorheological brake with an inner water-cooling mechanism

In order to improve the braking performance and reduce temperature rising of the magnetorheological (MR) brake during working condition, a multi-disc MR brake with an inner water-cooling mechanism is developed in this paper. The effective damping gaps are increased to eight sections by the four brake discs, which enhance the braking performance. An inner water-cooling mechanism is designed in the MR brake to improve the heat dissipation. The structure and working principle of the multi-disc MR brake are introduced, and the mathematical model of the braking torque and transient temperature field are established. The electromagnetic field simulation and the heat-flow coupling simulation are conducted by COMSOL software. A test rig is setup to investigate the braking performance and heat dissipation characteristics. The experimental results indicate the maximum braking torque can reach 96.24 N·m. Additionally, after 20 s of continuous braking, the temperature rise of the MR brake with cooling water input is lower than that without cooling water input. Compared with the braking torque reduction without cooling water input, the braking torque reduction with cooling water input is smaller. It is shown that cooling structures in the MR brake have a positive impact on improving braking performance.

An Experimental Approach to Overcome the Fouling Issue in Micro Heat Exchangers

AbstractMicro heat exchangers improve heat and mass transfer compared to conventional heat exchangers, enabling more energy‐efficient applications. However, their sensitivity to fouling limits broader industrial application. This approach presents a combined investigation of fouling and cleaning in microscale heat exchangers using two test rigs. Individual sets of analysis methods are developed to improve the understanding of heat and mass transfer on the microscale. In addition to known methods, such as pressure loss analysis, newly developed and established image analysis techniques are used to monitor fouling and cleaning. Based on the presented methods, it is possible to predict the initial position of thermally induced fouling and to demonstrate the applicability of automated cleaning on the microscale.