Full-scale Test Rig Research Articles

Structural behavior of solid expandable tubular undergoes radial expansion process – Analytical, numerical, and experimental approaches

Today’s structures have to meet increasingly rigorous requirements during operation. The economic and human costs of failure during service impose a great responsibility on organizations and individuals who develop new products as well as those who select/integrate products in a final engineering design. A crucial aspect for successful product development and/or inclusion is the careful selection of the best material(s), derived from an informed awareness of the capabilities and opportunities afforded by all candidate materials, together with a design that takes full benefit of those competencies. Thick-wall tubular is an example where all these issues are playing a major role in deciding their industrial applications. Given for their desirable features of high strength and geometrical shape, they are widely used in aerospace, marine, military, automotive, oil and gas, and many other fields. This paper focuses on developing analytical solution to investigate the structural response of thick-wall tubulars undergo plastic deformation due to expanding them using a rigid mandrel of conical shape. Volume incompressible condition together with the Levy–Mises flow rule were used to develop the equations which relate the expansion ratio of the tubular to the length and thickness variations. Besides, Tresca’s yield criterion was used to include the plastic behavior of the tubular material. Further to this, a numerical model of the tubular expansion process was also developed using the commercial finite element software ABAQUS. Experiments of tubular expansion have been conducted using a full-scale test-rig in the Engineering Research Laboratory at Sultan Qaboos University to validate the analytical and numerical solutions. The developed analytical and numerical models are capable of predicting the stress field in the expansion zone, the force required for expansion, as well as the length and thickness variations induced in the tubular due to the expansion process. Comparison between analytical, experimental, and simulation results showed that a good agreement has been attained for various parameters.

Impact of design parameters on the performance of ultraviolet photocatalytic oxidation air cleaner

Ultraviolet photocatalytic oxidation (UV-PCO) is regarded as one of the promising technologies for air purification. Previous studies on UV-PCO of ethanol were performed in an ideal bench top reactors. However, this research is focused on UV-PCO of ethanol in full-scale open test rig which closely resembles the real application of this technology. Ethanol mineralization was investigated under several conditions including two types of UV-lamps (UVC and VUV) for two different photocatalysts under varied concentrations, airflow rate and relative humidity. In each case, removal efficiency and by-products yield were compared. Furthermore, possible mechanism for by-product formation is presented. Experimental results show that acetaldehyde and formaldehyde are the main by-products of ethanol. VUV lamps increase photocatalytic oxidation of ethanol compared to UVC lamps. The increase of relative humidity decreases UV-PCO of ethanol using both VUV and UVC lamps; however, the yield of by-products in the presence of VUV lamps increases while it decreases in the presence of UVC lamps. Higher flow rate results lower removal efficiency and consequently formation of less by-products. Improvement of reaction section by increasing the number of reactors leads to higher ethanol removal efficiency, less partial oxidation, lower amount of by-products and the complete mineralization of acetaldehyde.

Fatigue strength evaluation of a bogie frame for urban maglev train with fatigue test on full-scale test rig

This study evaluated experimentally static strength for bogie frame of an urban maglev train including performing fatigue analysis, cumulative damage and fatigue test based on a developed fatigue load and as a final outcome, aimed to propose a fatigue strength evaluation method for the bogie frame of urban maglev. The results of FEM analysis adopting load combinations showed that all data was under a fatigue limit of the butt welded joint made of A6005 in Goodman diagram. The cumulative fatigue damage was calculated at the highest level from a bolt connecting area of electromagnetic pole in casting block but the total sum was evaluated as D=0.808 based on 1×107 cycles, which indicates it did not exceed the failure criteria. In addition, as the results of fatigue test, there was no crack on the any position of the bogie frame with the outcomes that corresponded to the results of fatigue test.

Rail grade selection and friction management: a combined approach for optimising rail–wheel contact

To investigate the mechanisms behind rolling contact fatigue (RCF) and wear, a collaborative test program was conducted by voestalpine Schienen GmbH (Leoben, Austria) and Kelsan Technologies Corp. (a part of LB Foster Friction Management) on the full scale test rig of voestalpine. A reference grade was compared to a series of pearlitic rail grades under dry and friction modifier (FM) contact conditions. Rail and wheel profiles were collected at predefined intervals, allowing the calculation of wear rates. The initiation and development of RCF cracks were monitored using optical means and magnetic particle inspection. Metallographic sectioning of the samples was conducted to characterise crack growth and crack orientation as well as the evolution of surface and subsurface material flow. Additionally, the test rig results were compared to the results obtained from the extensive track test network of voestalpine and Kelsan to outline similarities and differences between test rig conditions and the conditions in track. The combination of rail grade, FM application and an appropriate maintenance strategy is seen to have a significant effect on the development and propagation of wear and RCF. This offers a huge potential for reducing the track LCC costs for the infrastructure owners.

A full scale test rig for assessment of abrasive wear of shackle chains

During industrial fishing are link chains used to drag the trawls and churning of the seabed. The latter application wears off the steel chain in less than 6 months. However, there has been no tribological research concerning full scale testing of shackle chains in presence of seawater and sand. We therefore designed a new test rig at Ghent University, Soete Laboratory. The test rig generates wear in a single shackle contact and uses full scale specimens with the correct geometry. This paper describes the design of the test rig, emphasizing two innovative features compared to ordinary wear test rigs. First one is the possibility to apply two types of relative motion between neighbouring shackles: planar and circular motion. The second novel feature is the supply of harsh environmental conditions like seawater, sand or a mixture of both. The presented results reveal the wear mechanism as abrasive wear. The wear rate is measured by weight reduction and chain elongation. Higher wear rates are found in case of circular relative motion and in case of environmental harsh conditions. The test rig can be used for the validation of new wear models or the comparison of materials.

Design and Experimental Validation of Hydraulic Yaw System for Multi MW Wind Turbine

To comply with the increasing demands for life time and reliability of wind turbines as these grow in size, new measures needs to be taken in the design of wind turbines and components hereof. One critical point is the initial testing of the components and systems before they are implemented in an actual turbine. Full scale hardware testing is both extremely expensive and time consuming, and so the wind turbine industry moves more towards simulations when testing.In order to meet these demands it is necessary to use valid system models of in order to introduce new technologies to the wind turbine market. A hydraulic yaw system is such a new technology, and so a mathematical model of the full scale system and test rig system is derived and compared to measurements from the system. This is done in order to have a validated model, which wind turbine manufacturers may use for test in their simulation environment. The model and the test rig are tested against different design load cases and the results are compared. The experiments show that the model is valid for comparing the overall dynamics of the hydraulic yaw system. Based on the results it is concluded that the model derived is suitable for testing of the dynamic behavior in wind turbine manufacturer's full scale aero elastic code.

Mechanism of fire spread on facades and the new Technical Report of EOTA “Large-scale fire performance testing of external wall cladding systems”

In many European countries it is a requirement to carry out large-scale tests using full-scale test rigs to evaluate the fire performance of external wall cladding systems. The reason for this is that the laboratory test methods (e.g. those according to EN 13501-1 or national standards) used for the classification of the reaction to fire performance of building materials are unsuitable for a realistic simulation of the fire performance of external wall cladding systems. The following reasons can be named: – Sample measurements are too low – Fire conditions are too low compared to the effect of fire on a facade due to flames venting from the window of a room with a fully developed fire – Limited reproduction of facade structures that may promote the spread of fire, such as the suction effect in the air space of ventilated external wall cladding – No ability to consider detailed formations, such as those around jambs in external wall openings or base finishings – No ability to consider structural fire safety measures. For these reasons it was discussed, shortly after the introduction of the European classification system for the reaction to fire performance of building materials in 2002, to include an additional test method for external wall cladding systems. The Fire Regulators Group (FRG), which advises the European Commission (EC) on fire safety matters, even created a working group to deal with this. Its mission was to create an appropriate standardisation mandate for CEN. After intensive preparations it presented the draft mandate in autumn 2004 [1], which contained the key points for the test standard to be developed by CEN. In addition to this work in the FRG, detailed justifications explaining why such a full-scale test method was necessary for the evaluation of the fire performance of external wall cladding systems were submitted to the services of the European Commission by several Member StateMember States of the EU. Despite this, the EC decided in autumn 2005 not to issue this standardisation mandate. The reason was submitted to the Standing Committee on Construction at the EC in the document CONSTRUCT 05/716rev.1 [2]. However, since the European Organisation for Technical Assessment (EOTA) published or was working on a series of guidelines for the granting of European Technical Approvals (ETA) for construction kits for the fabrication of external wall cladding systems at the time, EOTA received through [2] the task of developing a suitable test method for these products. For this purpose a small working group of representatives from different European approval bodies was formed.

Experimental Investigation of Wheel/Rail Rolling Contact at Railhead Edge

Wheel-rail rolling contact at railhead edge, such as a gap in an insulated rail joint, is a complex problem; there are only limited analytical, numerical and experimental studies available on this problem in the academic literature. This paper describes experimental and numerical investigations of railhead strains in the vicinity of the edge under the contact of a loaded wheel. A full-scale test rig was developed to cyclically apply wheel/rail rolling contact load to the edge zone of the railhead. An image analysis technique was employed to determine the railhead vertical, lateral and shear strain components. The vertical strains determined using the image analysis method have been validated with the strain gauge measurements and used for the calibration of a 3D nonlinear Finite Element Model (FEM) that simulates the wheel/rail contact at the railhead edge and use suitable boundary conditions commensurate to the experimental setup. The FEM was then used to determine other states of strains.

Rolling Contact Fatigue of Wheel and Rail

Abstract This investigation describes rolling contact fatigue phenomena in the wheel/rail-contact area of railway vehicles. In the scope of this paper new calculation, experimental results of stresses and strains within the wheel as well as a new method the determination of fatigue strength are presented. The stress fields in railway wheels introduced by different loads are calculated using the finite element method. The results are validated on a full-scale test rig. The results of the measurements are used to draw conclusions for the fatigue strength of wheels. Furthermore, the fast and cost saving “PHYBALLIT” method for the determination of fatigue properties is described.

Intelligent Pitch Control for a 2MW Wind Turbine

The objective of the paper is to develop a novel intelligent pitch control system of a 2MW wind turbine driven by variable-speed hydraulic pump-controlled system. For realizing the intelligent pitch controller, self-organizing fuzzy sliding mode control, which combines fuzzy sliding mode control and self-organizing modifier, is proposed. In order to verify the proposed concept experimentally, a full-scale test rig of the hydraulic pitch control system of a 2MW wind turbine blades, including a novel mechanism of pitch control, a variable-speed hydraulic pump-controlled system, a disturbance system and a PC-Based control system, are designed and set up. The variable-speed pump-controlled hydraulic servo system contains an AC servo motor and a constant displacement hydraulic piston pump. In order to compare the control performance, the pitch control experiments by fuzzy sliding mode control and by self-organizing fuzzy sliding mode control are implemented respectively for different path profiles and different disturbance torque. Finally, the experimental results clarify that the pitch control controlled by self-organizing fuzzy sliding mode control can perform better than that controlled by fuzzy sliding mode control.

An assessment of electrostatic ignition hazards associated with fuel flow through plastic pipes at roadside filling stations

Abstract The use of electrically insulating synthetic materials, such as high-density polyethylene (HDPE), for fuel pipelines and other fuel handling components is now widespread. It is well reported however that the flow of fuel under certain conditions in plastic pipes can produce measurable levels of electrostatic charge. This paper describes in detail a full-scale experimental test rig simulating a filling station layout – in particular the conditions existing during road tanker delivery of high-charging fuels. It presents data from a series of electrostatic measurements, discusses results and draws conclusions with regard to existing safety margins and precautions for safe operation.

Development of a 3D Parallel Mechanism Robot Arm with Three Vertical-Axial Pneumatic Actuators Combined with a Stereo Vision System

This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot’s end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H∞ tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to verify the feasibility of the proposed parallel mechanism robot driven by three vertical pneumatic servo actuators, a full-scale test rig of the proposed parallel mechanism pneumatic robot is set up. Thus, simulations and experiments for different complex 3D motion profiles of the robot end-effector can be successfully achieved. The desired, the actual and the calculated 3D position of the end-effector can be compared in the complex 3D motion control.

Review and classification of fretting fatigue test rigs

There is no standard or generally accepted test rig for fretting fatigue experiments. Therefore,researchers adopt an existing concept, or build a new test rig that meets their specific requirements.However, too many different test rigs may be disadvantageous because the results of two different test rigsare hard to compare. The increasing amount of diversity is mainly caused by the lack of a recent literaturesurvey on fretting fatigue test rigs. In 1994, Hills and Nowell described a few test rigs in Mechanics OfFretting Fatigue. In this study, the authors made a classification of test rigs based on the contact geometry,which is determined by the test specimens, not by the test rig itself.Ghent University, Laboratory Soete, BelgiumThe authors of this article present a review of the available literature, and present a classification based onthe properties of test rigs. Fretting fatigue test rigs are first divided in two categories based on the geometryof the test specimen: full scale and coupon scale test rigs. The latter are mostly used to perform researchand are subdivided in categories based on increasing functionalities. This is the ability to apply a fatigueload, a constant normal force, and an alternating slip in the range of some micrometers. In time, from thefifties until now, progress has been seen in the design of fretting fatigue test rigs. More parameters can becontrolled during experiments and more measuring techniques are incorporated. State of the art test rigsare classified in the last category with most functionalities, but still have imperfections. Future designerscan use this article to classify their needs, or help to design a better test rig knowing the imperfections ofthe state of the art test rigs.

State-of-the-art methods for studying air distributions in commercial airliner cabins

Air distributions in commercial airliner cabins are crucial for creating a thermally comfortable and healthy cabin environment. This paper reviews the methods used in predicting, designing, and analyzing air distributions in the cabins, among which experimental measurements and numerical simulations are the two popular ones. The experimental measurements have usually been seen as more reliable although they are more expensive and time consuming. Most of the numerical simulations use Computational Fluid Dynamics (CFD) that can provide effectively detailed information. Numerous applications using the two methods can be found in the literature for studying air distributions in aircraft cabins, including investigations on more reliable and accurate models. The review in the paper shows that the studies using both experimental measurements and computer simulations are becoming popular. And it is necessary to use a full-scale test rig to obtain reliable and high quality experimental data. What’s more, the hybrid CFD models are found to be rather promising for simulating air distributions in airliner cabins.

A novel pitch control system for a wind turbine driven by a variable-speed pump-controlled hydraulic servo system

The paper aims to develop a novel pitch control system for a large wind turbine driven by a variable-speed pump-controlled hydraulic servo system. To perform practical pitch control experiments, a full-scale test rig of the hydraulic pitch control system for a 2 MW wind turbine’s blade, including a novel pitch control mechanism, a variable-speed pump-controlled hydraulic servo system, a disturbance system and a PC-based control system, is designed and set up. The variable-speed pump-controlled hydraulic servo system, containing an AC servo motor, a constant displacement hydraulic piston pump two differential hydraulic cylinders and hydraulic circuits, achieved high response and high energy efficiency, so it is suitable for wind turbine applications. Besides, to implement the pitch control in the proposed novel pitch control system, an adaptive fuzzy controller with self-tuning fuzzy sliding-mode compensation (AFC-STFSMC) is developed to design the pitch controller. Finally, the developed variable-speed pump-controlled hydraulic servo system was built and verified for the path tracking control and path-positioning control of the pitch control of the wind turbines by practical experiments in a full-scale test rig under different path profiles, load torques, and random wind speeds.

Synthetic Lubricants in Hydrodynamic Journal Bearings: Experimental Results

Synthetic lubricants and additives have seen many major improvements in recent years. However, very little is known about the performance peculiarities of these new lubricants in actual machines. To fill this gap, a new full-scale hydro-dynamic journal bearing test rig has been constructed to evaluate the behavior of conventional and new bearing designs, synthetic lubricants and variations in operating parameters. This test rig’s bearing has diameter 180 mm with measuring capabilities including continuous film thickness and film pressure as well as temperature. The new machine was used to compare a number of synthetic lubricants to mineral based lubricants, finding that performance of the synthetic lubricants was superior to their mineral based counterparts of much higher viscosity grade. These tests showed that high viscosity index (VI) synthetic lubricants had higher viscosity in the region of maximum pressure and lower viscosity elsewhere in the bearing than similar mineral based lubricants. This reduction in viscosity in low pressure zones was found to produce a measurable reduction in friction and power loss in the bearing system. This paper provides comparative performance results of several formulations of current and future turbine oils from measurements of losses, oil film thickness, and temperature under a range of operating parameters. Lubricants tested include ISO VG68 and VG32 mineral based turbine oils (VG68 and VG32), ISO VG32 synthetic ester based oil (SE32), two ISO VG22 synthetic ester based oils (SE22 and SV22), and ISO VG15 synthetic ester based oil (SE15). It was found that SE32 and VG68 provided similar performance at lower speeds while SV22 provided similar performance to VG68 at the highest speed. Likewise, SE22 and SV22 provided similar performance to VG32 at low speeds while SE15 provided similar performance to VG32 at medium to higher speeds. Generally, the results demonstrate the potential for replacing mineral based lubricants with high performance synthetic lubricants of significantly lower viscosity grade without sacrificing bearing safety.

Simulation and experimental investigation on adaptive multi-order proportional-integral control for pneumatically actuated active suspension system using knowledge-based fuzzy

This paper presents an adaptive multi-order proportional-integral (PI) control called knowledge-based fuzzy (KBF) multi-order PI control. The controller consists of the two-control loops namely inner loop controller for force tracking control of the pneumatic actuator and outer loop controller to reject the effects of road-induced disturbances. The outer loop controller utilised KBF multi-order PI control while the on-off controller is used in the inner loop controller to compromise with the existing solenoid valve in the pneumatic actuation system. Performance of the proposed controller is compared with the multi-order PI controller without adaptive scheme as well as the existing passive suspension system. Simulation studies are presented in time domain simulation while the experimental evaluation is conducted on a full-scale quarter car test rig. In general, it can be reported that the proposed control scheme is able to provide significant improvement in terms of body states compared to its counterparts. The proposed scheme is also easy to realise in practice due to its simple structure.

Prediction of wear and plastic flow in rails—Test rig results, model calibration and numerical prediction

Conventionally, laboratory measurements under idealized conditions are used to establish parameters needed in different kinds of wear models. This paper presents a procedure for determining the Archard's wear coefficient from data collected in a full-scale wheel-rail test rig, i.e. under realistic loading conditions. Moreover, a simulation procedure capable of simulating rail profile evolution in conformal contacts incorporating both wear and plasticity is presented. In each simulation step, dynamic responses are calculated using the commercial vehicle-track interaction software GENSYS. The conformal contact is treated by applying a multi-Hertzian approach. To account for plastic deformations, a 20 elasto-plastic FE analysis is carried out in conjunction with a 3D local contact analysis in the commercial finite element (FE) software ABAQUS. It is shown that, due to the conformal contact, elastic shakedown is obtained after only a few load cycles and is therefore disregarded in the subsequent analyses. Quantitatively good results, in terms of worn-off area and shape of the worn profile, are presented for simulations between 20k and 100k load cycles. However, dependence between the chosen wear step length and the profiles obtained from the simulations is found.

RCF and wear in theory and practice—The influence of rail grade on wear and RCF

Abstract This paper investigates the wear and RCF behaviour of several pearlitic and bainitic rail steels on a full scale test rig at voestalpine Schienen GmbH and also in several track tests. On the test rig a clear dependence between hardness of the pearlitic grades and the resistance against wear and RCF is seen. The same is found in track tests however the results especially in low wear regimes concerning higher hardness grades are not as distinct as on the test rig. Track behaviour also indicated the improved RCF resistance of higher hardness steels. Bainitic steels show a slightly different behaviour – the wear resistance is reduced compared to a pearlitic steel with the same hardness level though the RCF resistance is higher (both on the rig and in track if data available). Although the trends are consistent on the rig and in track, the absolute values concerning wear and RCF differ. Finally an outlook concerning modifications and upgrades for the test rig to shorten this gap is given.

Rolling contact fatigue prediction for rails and comparisons with test rig results

Tests in a full-scale roller rig, a full-scale linear test rig, and a twin-disc machine are numerically evaluated and compared in terms of rolling contact fatigue loading. From previously evaluated contact patch sizes, a Wöhler curve relationship is established and matched towards experimentally established fatigue lives. In addition, non-linear finite-element simulations are carried out. Key data needed for the numerical evaluations, as well as difficulties in translating experimental data to numerical models are highlighted. A key parameter here is the interfacial wheel—rail friction. Additional simulations were carried out to establish the latter. However, the conformal contact in the linear test rig makes such simulations very uncertain.