bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Driven Pump Control of Hydraulic Cylinder for Rapid Vertical Position Control of Heavy Loads: Energy Efficiency Including Effects of Damping and Load Compensation
Authors: Kauranne Heikki , Koitto Teemu , Calonius Olof , Minav Tatiana , Pietola Matti 
Published: November 2018

The ever-tightening government-enforced regulations for more energy efficient and less polluting machines and the simultaneous fast development of electric drives have caused hydraulic systems to lose ground to electric drives. One promising solution to improve the status of hydraulics in this competition are the Direct Driven Hydraulic (DDH) systems, aka electro-hydraulic actuators (EHAs), which are characterized by a closed circuit type and a servo motor driven speed-controlled pump controlling the actuator. Due to this topology, they offer a possibility of reaching higher energy efficiencies compared to traditional open circuit type valve-controlled systems and simultaneously they offer the high accuracy and dynamics of these.
Typical applications where DDHs have been used are, in the area of mobile equipment, modern commercial and military aircrafts and some lift trucks, and in the area of stationary applications, mostly presses. In all of these, the actuators produce relatively slow motions.
In this experimental study, a DDH system is applied to a stationary industrial vertical position control application where a very rapid movement of a heavy load is required. This brings out some unwanted fluctuation phenomena not encountered with slower motion velocities. Here we are striving for avoiding these phenomena by adding damping to the system. In addition, it is studied whether the good energy efficiency of DDH systems could be enhanced with load-compensation.
The presented measurement results include the system behavior regarding the smoothness of positioning, the fluctuations of pressures, forces, and power, and finally the energy consumption with three different system configurations: basic DDH, load-compensated DDH, and load-compensated and damped DDH. The measured energy consumptions are compared against results gained in simulating a conventional valve-controlled system driving the same application.
The measurement results manifest that energy consumption wise significant benefits are achievable with DDH, especially in combination with hydraulic load compensation. However, without added damping the motion involved marked vibrations in the end of the upward and downward strokes. Added damping eliminated these vibrations, but at the cost of reduced energy efficiency. Due to this, the solution for the fluctuation and vibration problem should be sought by developing a control strategy that produces a smoother but as fast motion.
Low Speed Performance of Axial Piston Machines
Authors: Achten Peter , Potma Jeroen , Achten Jasper 
Published: November 2018

Low speed operation of axial piston motors has always been a critical performance issue. The breakaway torque determines the capacity of a motor to move a certain load from standstill conditions. In addition, the low speed performance has also become a critical performance parameter for pumps being applied in frequency controlled electro-hydraulic actuators. Yet, there is almost no information available about the low speed and breakaway characteristics of piston pumps and motors.
A new test bench has been constructed to measure these characteristics [1]. The new bench allows operation of hydrostatic machines below 1 rpm, down to 0.009 rpm. At these conditions, the main tribological interfaces operate in the solid friction domain, at which the friction losses are at a maximum value.
This research describes and analysis the test results for a number of different axial piston pumps and motors: two slipper type motors, one slipper type pump and a floating cup pump/motor. The tests have been performed at various operating pressures and operating speeds. Furthermore, the breakaway torque has also been measured after letting the hydrostatic motor stand still for one or more days.
Addressing Closed-Chain Dynamics for High-Precision Control of Hydraulic Cylinder Actuated Manipulators
Authors: Koivumäki Janne , Zhu Wen-Hong , Mattila Jouni 
Published: November 2018

Nonlinear model-based (NMB) control methods have been shown (both in theory and in practice) to provide the most advanced control performance for highly nonlinear hydraulic manipulators. In these methods, the inverse dynamics of a system are used to proactively generate the system actuation forces from the desired motion dynamics. To model the inverse dynamics in articulated systems, the Lagrange dynamics and the Newton-Euler dynamics are the most common methods.
In hydraulic cylinder actuated manipulators, a linear motion of the cylinder can be converted to a rotational joint motion between two links, creating closed-chain structures in the system. In Lagrange-dynamics-based control methods, the closed-chain structures are typically treated as an open-chain structure, which may raise the question of inaccurate system modeling. Contrary, the virtual decomposition control (VDC) approach is the first rigorous NMB control method to take full advantage of Newton-Euler dynamics, allowing to address the system nonlinear dynamics without imposing additional approximations.
In VDC, the actuated closed-chain structures can be virtually decomposed to open chain structures. To address the dynamics between the decomposed open chains, three specific terms (namely two load distribution factors and an internal force vector) need to be addressed. However, analytical solutions for these terms cannot be found in the literature. This paper provides the detailed solutions for these terms, which are further needed in a high-precision control of hydraulic robotic manipulators.
Foundation for Virtual Prototyping of Mechanical Power Management Functions in Actuators
Authors: Mare Jean-Charles , Akitani Silvio 
Published: November 2018

Beside the main functions related to the control and transformation of power, safety-critical electromechanical actuators require many additional functions for power routing, protection and limitation. In practice, these functions are implemented mechanically because their realization at motor drive level is not acceptable for performance and reliability reasons. Contact forces play a major role in these mechanical devices (e.g. endstop, lock, brake, torque limiter, etc.), being either functional to serve the need, or parasitic due to their alteration of performance. The virtual prototyping of such mechanical power management functions therefore requires normal and tangent forces to be modelled with the right level of realism and reduced complexity.
This communication provides some proposals to be used as foundation for the system-level modelling and simulation of these types of mechanical power elements that can be found in electromechanical actuators. Special focus is given to the model architecting, decomposition and block-diagram implementation, using the example of normal contact forces. The illustrative example concerns an integrated landing gear extension/retraction electromechanical actuator which embeds free-fall and autolock features. It shows how a well implemented single model (e.g. generic normal contact force model) combined with a right model decomposition can meet various modelling needs (e.g. droppable end-stop, lock and shearable axial stop).
The proposed models are made compatible for integration in a 2x1D mechanical model architecture (axial and rotational motion) developed by the authors in previous reported work.
Modelling and Simulation of a Cartridge Pressure Amplifier
Authors: Zardin Barbara , Cillo Giovanni , Borghi Massimo , Zavadinka Peter , Hanusovsky Juraj 
Published: November 2018

Hydraulic pressure amplifiers of the cylinder type are much appreciated in hydraulic systems where high pressure work is needed only for a limited period of time, while during the remaining duty cycle the system operates at a standard level of pressure. The use of these elements allows the designer not to oversize the system, which will perform the work with a considerable power saving, confining the high pressure operation only on the side of the hydraulic cylinder.
This works describes the modelling and simulation of a compact cartridge pressure amplifier for linear actuators. The cartridge amplifier is able to double or more the pressure in the system when needed and to not interfere during normal operation of the system. It has been designed to fit in the narrow space of the rod of normal hydraulic cylinder, being extremely compact and efficient. Designing such a component and the study of the main design parameters influence have required a strong work of modelling and simulation, performed with a lumped parameters approach to depict the dynamic behaviour of the amplifier. This work illustrates the building of the model and a first comparison between simulated and experimental data. Moreover, the simulation activity is enlarged to analysis of the influence of some operating and design parameters on the amplifier dynamic behavior.
Effect of Driver and Work Cycle on Losses of a Loader
Authors: Tikkanen Seppo , Ahola Ville , Koskela Elias 
Published: November 2018

Improving the energy efficiency of mobile machines requires information about the initial state of the machine. This information includes knowledge of the systems and their components and of course, measurement data that is acquired during typical operation. Machine manufacturers and research institutes have carried out extensive measurement programs during the last decade. Usually, the published studies concentrated on one work cycle, the machines studied were operated by humans, and it is shown that productivity and fuel consumption are dependent on the machine design, work cycle and operator.
This study concentrates on a detailed analysis of the energy consumption of a municipal loader during measured work tasks. The goal was to find out how much the driver and work cycle affect the machine’s energy consumption and energy distribution.
To evaluate the real fuel consumption and energy distribution, the measurements consisted of two different work cycles that were driven by two drivers with different skill levels. The first cycle was the classic short wheel loader loading cycle, the Y-cycle. In this task, the loader was equipped with a bucket, and a pile of gravel was moved from pile A to pile B in a Y-pattern. The second cycle was the load and carry cycle in which the driver picked up a load with the forklift attachment and carried the load over a predefined distance.
The major finding was that the impact of the driver and the work cycle is considerable in fuel consumption. The difference is also seen in the energy distribution in the hydraulic system and in losses and how the losses are divided. Therefore, it can be stated that test results with one driver or one cycle should not be generalized without concern and judgement of novel concepts requires several tests with different drivers and work cycles.
Modeling the Efficiency of External Gear Pumps Based on Similarity Considerations
Authors: Schänzle C. , Störmer N. , Pelz P. F. 
Published: November 2018

Gear pumps are used in numerous different applications and industrial sectors. However, when selecting a suitable gear pump for a specified application, manufacturers are often confronted with a lack of comparable measurement data for the desired combination of operating conditions and pumping fluid. Consequently, an estimation of the volume flow rate and the power consumption of a pump under the operating conditions of the application is necessary.
In this context, this paper discusses the application of similarity on external gear pumps and presents its validation by means of measured pump characteristics. Seven gear pumps of different displacement volume are measured at different operating conditions varying pressure, rotational speed and the viscosity of the pumping fluid. The validation results prove that similarity is useful to represent a pump’s characteristic over a wide operating range. The prediction of the volume flow rate and the power consumption at a changed viscosity show good accuracy. However, the scaling of the pump characteristic based on the displacement volume show contradictory results.
Application of Leakage Rates Measured on Scaled Cask or Component Models to the Package Containment Safety Assessment
Authors: Rolle Annette , Ballheimer Viktor , Neumeyer Tino , Wille Frank 
Published: November 2018

The containment systems of transport and storage casks for spent fuel and high level radioactive waste usually include bolted lids with metallic or elastomeric seals. The mechanical and thermal loadings associated with the routine, normal and accident conditions of transport can have a significant effect on the leak tightness of such containment system.
Scaled cask models are often used for providing the required mechanical and thermal tests series. Leak tests have been conducted on those models.
It is also common practice to use scaled component tests to investigate the influence of deformations or displacements of the lids and the seals on the standard leakage rate as well as to study the temperature and time depending alteration of the seals.
In this paper questions of the transferability of scaled test results to the full size design of the containment system will be discussed.
Dynamic Analysis and Design Methods for Combustion Turbine Exhaust Silencers Employing Acoustical Baffles
Authors: Gjinolli Agron E. , Dorgan Jason E. , Ray Elden F. 
Published: November 2018

Combustion turbines are frequently used because they provide the most power in the smallest footprint and their modular design makes them an economical choice. These machines are used across all land-based industries as well as marine applications. The exhaust system must perform its basic function of conducting exhaust gases, which can be as high as 1250° F (675° C), safely away from the adjacent equipment and workers, and mitigate the exhaust noise under a wide range of requirements and conditions. In addition, new requirements limit shell temperatures and exhaust leakage to prevent fire or explosion of fuel gas that may leak from equipment (ATEX).
This paper presents a review of the analytical processes used in the development of a silencer system to achieve optimal performance metrics. These systems are typically comprised of parallel baffles for a wide range of conditions including aero-acoustical performance, system pressure and high flow rates, thermal stresses, environmental conditions (ocean, seismic and wind), flow-induced vibration, corrosion, and fatigue – design life analysis. The specific requirements of the baffle design will be discussed through a specific case study relative to typical rectilinear (parallel) baffles used in many installations, including land-based power generation plants (Figure 1), and offshore platforms (Figure 2).
This paper will discuss the analytical methods used to address these challenges via a case study. A combination of static, vibration-pulsation and dynamic structural analysis with specific attention to the seismic analysis of the parallel baffles used in skirt and structural steel supported vessels, as well as acoustical design and flow modeling techniques are used to evaluate the design options.
Comparison of ASME XI and BS7910 Allowable Surface Flaw Size Evaluation Procedures in Piping Components
Authors: Kuutti Juha , Oinonen Ahti 
Published: November 2018

This paper presents a failure assessment diagram (FAD) and crack size based comparison of the ASME BVPC Section XI Nonmandatory Appendix C and Nonmandatory Appendix H and the British Standard BS 7910:2013 Option 1 assessment methods. The Section XI appendix C evaluates the acceptability of a flaw by determining the expected failure mechanism and by comparing the flaw size with allowable flaw size limits or by comparing the applied stress to the allowable stress. The Section XI appendix H and BS7910 employ a FAD based approach that simultaneously considers brittle fracture, ductile crack extension prior to reaching the limit load and exceedance of the limit load due to the gross plasticity in the cross section. The assessment is performed by calculating the assessment point coordinates and evaluating whether the point is located on the safe side of the FAD line. The three methods are compared for simplified austenitic and ferritic pipes under internal pressure and bending loads with postulated axial and circumferential internal surface flaws. The methods are applied to generate limiting flaw size diagrams for each component under the specified loads. Additionally, the limiting flaw size results are presented in the FAD plots. To maintain comparability between the results, identical input data are used with each analysis approach but using the method-specific formulae.
The performed comparison shows that most often the limiting state is governed by the 75 % flaw depth rule in Section XI article IWB-3640. The largest differences between the methods are observed for cracks with a high length to depth ratio. The difference to the tabulated allowable planar flaws in Article IWB-3514 is typically high. When increasing the applied load to values approaching the limit load, differences in the limiting flaw sizes between the methods are observed, mostly due to the different limit load models and different assumptions on the utilization of the post-yield capacity.
Besides the presented flaw size comparison, the paper presents a quick tool suitable for ranking different piping segments based on failure potential and for quick scoping evaluations of indications found in inspections. The case specific scoping tool is a map of yearly flaw size lines providing the information on which flaw sizes would grow to the final limiting size in a specified timeframe.
Benchmark of Finite Elements and Extended-Finite Elements Methods for Stress Intensity Factors and Crack Propagation
Authors: Lacroix Rémi , Caron Axelle , Dischert Sandrine , Deschanels Hubert , Pignol Moïse 
Published: November 2018

Stress intensity factors (SIFs) are a major feature in regulatory analyses of Nuclear Power Plants (NPP) components, as they allow to rule on the acceptability of defects when compared to a critical experimental value (K1c). Simplified and robust evaluations of SIFs have been provided in major regulations standards for cracks having usual geometries and locations in major components.
However, their evaluations still require a significant effort in the case of important deviations of the geometry of cracks regarding the usual semi-elliptical shape, or in the case of specific geometries of components, and specific locations of cracks in components. In these cases, time-consuming Finite Element meshes must be constructed, either manually or using semi-automatical tools, to represent the components and its defect(s). This method can become particularly costly, especially in the case of fatigue crack propagation.
The eXtended-Finite Elements Method (X-FEM) has been proposed to overcome this issue. The representation of the defect is carried out by the level-set method, and specific enrichment functions are used to represent the solution near the crack surface and the crack front.
This paper proposes a benchmark of numerical predictions of stress intensity factors using SYSTUS software [5]. It will be based on:
a) Available analytical solutions;
b) Classical Finite Element method;
c) EXtended-Finite Elements Method.
The classical case of a circular and elliptical crack in a semiinfinite body is first presented. Then the case of a circumferential crack in a valve under a thermo-mechanical loading is analyzed. The accuracy of the different methods is then compared and discussed.
Effect of Static Load Components in Seismic Loading on Gross Plastic Deformation on Structure
Authors: Kai Satoru , Otani Akihito 
Published: November 2018

In general, a seismic load acting on a structure is considered to potentially cause unstable gross plastic deformation that is called as plastic collapse, because the seismic load induce an inertia force on the structure which may act as an external force onto the structure. The past researches by the authors to clarify the characteristic of seismic loads found that the way of the seismic response on the structure is driven by the correlation between the seismic loading and the natural frequency of the structure while only the dynamic loads are acting. On the other hand, existence of relatively large sustained loads such as a dead weight was also recognized to promote an unstable gross plastic deformation in the past experimental studies.
Based on the previous studies, two factors that are the sustained load level and the correlation other than the dynamic load level are expected to play an important role in determining the dynamic behavior of a structure and potentially governing the failure mode. The several elastic-plastic analyses with an elastic-perfect-plastic (EPP) material property and a simplified structure were conducted in this paper by slightly changing the level of the sustained loads and the dynamic loads. From the analytical results focusing on the ratchet deformations and residual deformations, the level of the sustained load on the structure was found to promote ratcheting behavior on the structure with a specific trend and significantly affect the dynamic behavior at the conceptual conditions which were defined and identified in the past researches.
Study on the Predictive Evaluation Method of Nonlinear Sloshing Wave Height of Cylindrical Tanks: Part 1 — Shaking Table Test Results and Verification Results of Analytical Method for Nonlinear Sloshing
Authors: Morita Hideyuki , Takata Tomoshige , Madokoro Hideki , Sago Hiromi , Murakami Hisatomo , Yokoi Shinobu , Yamamoto Tomohiko 
Published: November 2018

When cylindrical tanks installed on the ground, such as oil tanks and liquid storage tanks, receive strong seismic waves, including the long-period component, motion of the free liquid surface inside the tank called sloshing may occur. If high-amplitude sloshing occurs and the waves collide with the tank roof, it may lead to accidents such as damage to the tank roof or outflow of internal liquid. Therefore, it is important to predict the wave height of sloshing generated by an earthquake input.
Sloshing is vibration of the free liquid surface, and when the sloshing wave height is small, it can be approximated with a linear vibration model. In that case, the velocity-response-spectrum method using velocity potential can estimate the sloshing wave height under an earthquake input. However, when the sloshing wave height increases and the sloshing becomes nonlinear, it is necessary to evaluate the wave height using other methods such as numerical analysis.
Taking into consideration that design earthquake levels tend to increase and the use of seismic isolation mechanisms has continued to spread in recent years, the amplitude of the long-period components of an earthquake input which act on cylindrical tanks may also increase. Therefore, although the evaluation of nonlinear sloshing wave height is important, there are few examples which quantitatively evaluate the wave height of nonlinear sloshing.
The purpose of this study is to construct a simple evaluation technique of a nonlinear sloshing wave height of cylindrical tanks. In this study, the shaking table test using the small cylindrical tank for studying the behavior of nonlinear sloshing was carried out. Furthermore, verification of the flow-analysis technique described by previous report (PVP2017-65313) was carried out by comparing with test results. As a result, the data for constructing an evaluation technique has been acquired. Moreover, the validity of the flow-analysis technique was has been verified.