Hydraulic Ram Research Articles

Influence of draw restraining force on the springback in advanced high strength steels

Draw beads are used in sheet metal forming processes to regulate material flow and achieve higher quality in the parts. The draw beads impose draw restraining force on the blank which eliminates defects such as wrinkling, tearing and reduces springback. In a draw-bend test, the draw restraining force is imitated by the back force applied through a hydraulic ram. As the back force increases, large strain is induced which reduces springback tendency. This study evaluates the influence of back force on the springback behavior in advanced high strength steel (AHSS). Three grades of dual-phase steel, namely DP600, DP800, DP980, are used with normalized back forces ranging from 0.5 to 1.1. The springback decreases as the back force increases. Anticlastic curvature as well as curl radius has significant influence on the springback behavior of dual phase steels.

A NEW METHOD FOR MONITORING AND TUNING PLASTIC INJECTION MOLDING MACHINES

This paper presents a new method for monitoring and tuning plastic injection molding machines. It consists of two parts: quality monitoring using the Radial Basis Function Neural Network (RBFNN), and operation parameter tuning using Support Vector Machine (SVM) and Virtual Search Method (VSM). The quality is measured by the part weight, which is estimated using hydraulic pressure signal and ram position signals through a RBFNN. The tuning is aimed at finding the optimal setting of the machine operation condition. It is done in two steps: first, a SVM model is established as the virtual model to track the part quality variations, and then the quality variation is minimized by tuning the machine operating conditions using VSM. The new method is validated by two sets of practical experiments, and the results are very promising.

A control method of guide rolls in 3D-FE simulation of ring rolling

3D-FE simulation has become an indispensable approach to develop advanced ring rolling technologies, and a perfect 3D-FE ring rolling model is the basic demand of the simulation. How to control the movement of guide rolls reasonably in the model is one of the key problems urgently to be solved, particularly for rings complicated in shape or large in dimension or with high precision. In this paper, a method to control the guide rolls by the hydraulic adjustment mechanism is explored and realized in 3D-FE ring rolling model for the first time, and the key technologies, such as the parameter design of the linkage assembly and critical pressure of the hydraulic ram, are also proposed. Moreover, the difficulty in determining the liquid flow rate out of the hydraulic ram is solved by combining dichotomy with numerical simulation results. Based on the elastic–plastic dynamic finite element method under the ABAQUS software environment, the 3D-FE cold ring rolling model with hydraulic adjustment mechanism has been built, and the side spread of rectangular-section rings and the final section configuration of T-shaped ring have been analyzed. Good agreements between the calculating results and experimental ones prove the validity of the improved cold ring rolling model, and consequently the developed guide roll control method is also valid. Meanwhile, the circularity and oscillation of ring show that the rings are kept circular and stable very well during the process. Therefore the guide roll control method developed is suitable and reliable, particularly for rings complicated in shape or large in dimension or with high precision.

Severn Trent Water awards contract for ram pumps

Severn Trent Water awards contract for ram pumps

A Case Study of Right Ventricular Rupture in an Elderly Victim of Motor Vehicle Crash

Cardiac trauma fatalities occur in 22% of victims of motor vehicle crash. Blunt cardiac trauma may result in myocardial rupture. Mechanisms of injury include compression, deceleration, laceration, and "hydraulic ram" effect. Diagnosis is difficult because of coexisting injuries and the lack of evidence-based protocols. Physiological changes in the elderly and the presence of comorbid illness result in poor survival rates when myocardial rupture occurs. Trauma nurses must be prepared to provide end-of-life care related to the poor outcome associated with myocardial rupture. This case study reports a right ventricular rupture in an elderly patient involved in a frontal motor vehicle crash.

A wave-to-wire model of the SEAREV wave energy converter

This paper describes a numerical wave-to-wire model of the second-generation wave energy converter called SEAREV. Governing equations are given in the time domain for the motion of the masses involved in the device and for the hydraulic power take-off (PTO) used to convert the motion into electricity. The hydrodynamic forces are derived using the standard linear potential theory. The memory term in the radiation force is replaced by additional states using the Prony method in order to change the equation of motion into the ordinary differential equation form. The PTO is composed of hydraulic rams, an accumulator, and a hydraulic generator, which delivers electricity when there is enough energy stored in the accumulator. Using the MATLAB Simulink tool, the equation of motion is solved to simulate the full device (including the power take-off) from the incident wave to the electricity delivered to the grid. Simulation results are presented in the paper and comparisons are made with a simpler PTO: a linear damper. They show that the torque applied to the hydraulic PTO must exceed a threshold to start absorbing energy, unlike the linear damping model. They also show that the power production can be very discontinuous, depending on the level of the incident wave power. This is due to the fact that the generator considered can transform the energy stored in the accumulator faster than the energy transmitted by the rams into the accumulator. It could therefore be interesting to use several generators to adapt the electrical energy production to the level of incident wave power, or a generator that could work efficiently at part load in order to achieve continuous energy production.

Electricity Generation Using Water Lifting Force

This study has exhibited the advantage of electricity generation using water lifting force and explained how it is effectively used. Water is a renewable energy source which can be used in electricity generation by using its lifting force (buoyant force). It is important that an electricity generating apparatus using gravity and buoyancy can curtail costs of power generation and prevent environmental pollution and prevent destruction of an ecosystem. The hydraulic ram is an attractive solution for electricity generation where a large gravity flow exists. The wave conversion plant using buoyancy chambers is another solution for electricity generation using water lifting force. There are a good many reasons that water lifting force will be used in future at many ranges for electricity generation.

The response of a simple welded structure under dynamic loading conditions

The ability of simple structures to absorb impact energy has a number of applications particularly in mitigation systems. This paper describes integrated modelling and experimental work to characterise the impact response of simple aluminium spheres when empty and filled with water. The experimental work identified the deformation modes and their relationship to impact velocity over a range of velocities up to 200m.s -1 and included studies of the impact of a single sphere against a rigid surface and the impact of a sphere on another sphere. The numerical modelling showed the importance of friction between the sphere and the impacting surfaces and the weld in controlling the deformation and failure modes. The weld controlled the onset and development of failure. The validation of the modelling studies in predicting the deformation response of the spheres allowed the construction of an iso-damage relationship to predict their response over a wide range of impact conditions. The inclusion of the water as a fill material provided a scaled impact vehicle to study hydraulic ram and the response of a range of fluid filled containers. This has particular relevance to'pressure vessels containing volatile explosive liquids and gases.

Results of studying the ash pneumatic transport from ash trap hoppers in a pulse-mode

The results of studying the effects of ash layer density and the method of dynamic impact on the ash ability to flow are presented. A scheme of a pneumatic impulse pump and that of an impulse-type ash removal and transport system of high operating performance are proposed.

Fabrication and Performance of Anode-Supported Micro-Tubular Solid Oxide Fuel Cells

A solid oxide fuel cell was fabricated using standard NiO/8YSZ cermet anode, 8mol% yttria stabilized zirconia (YSZ) electrolyte, and lanthanum strontium manganite cathode. The anodes were extruded using an hydraulic ram extruder. An electrolyte was deposited using a novel technique allowing obtaining a 3-5μm thin and dense YSZ layer. The cathode was deposited by brush painting. The cells were operated under different temperature and fuel conditions, and showed excellent performance of up approximately 0.6Wcm−2 at 890°C. Performance data as well as scanning electron microscopy micrographs of the cells are presented.

An overview of marine renewables in the UK: a synopsis of Michael Hay's presentation

An overview of marine renewables in the UK: a synopsis of Michael Hay's presentation

High Pressure Studies

In principle, the methods described elsewhere in this volume are available at high pressures (HP). Of course, “in principle” implies the availability of techniques for maintaining samples of a sufficient volume at the HP to allow observation of a signal. Compared to studies on the same material at ambient conditions, neutron scattering at HP is a flux hungry technique. The HP device, irrespective of its design, will necessarily force compromise between signal and parasitic scattering and absorption from the cell. Breakthroughs in HP neutron science therefore depend on novel HP cell and beamline design that maximize pressure, sample volume, and signal to noise discrimination. ### Overview and historical context Successful high-pressure structural studies using neutron scattering techniques date from at least the 1960s (Bloch et al. 1966; Lechner and Quittner 1966; Litvin et al. 1966; Brugger et al. 1967). Although early HP cell designs were installed at reactor sources (Paureau and Vettier 1975) it became clear the geometric restrictions associated with collecting data in the angular dispersive geometry lead to contributions from parasitic scattering from the high pressure cell. Typical of these early designs was the so-called “McWhan cell” (McWhan et al. 1974), a piston cylinder apparatus (Fig. 1⇓) with an alumina cylinder radially supported by compressing two steel plates with a hydraulic ram. This left a neutron window between the plates ~6 mm high and allowed a number of very important studies, with pressures up to 3 GPa achieved routinely. Despite difficulties at the higher pressures with poor counting statistics, and severe peak overlap problems because of diffraction from alumina, several important studies were carried out including careful work on the high pressure phases of ice, D2O-VI, -VII and VIII (Kuhs et al. 1984). Apart from parasitic scattering from the HP cell, another disadvantage was the requirement that …

Low Proof Load Prediction of Ultimate Loads of Fiberglass/Epoxy Resin I-Beams Using Acoustic Emission

Abstract Acoustic emission (AE) nondestructive testing was used to monitor fiberglass/epoxy I-beams. The experiment consisted of loading the I-beams in cantilever fashion with a hydraulic ram. While testing, AE waveforms were collected from the onset of loading to failure. After acquisition, the AE data from each test were filtered to include only data collected up to 50 % of the theoretical ultimate load for further analysis. A Kohonen self-organizing map (SOM) was utilized to separate individual data points into failure mechanism clusters. Then a multiple linear regression analysis was performed using the percentage of hits associated with each failure mechanism along with the epoxy type to develop a prediction equation. The results of this analysis provided a prediction to within a 36.0 % error. A second analysis was performed utilizing a back-propagation neural network. The inputs to the network included a categorical variable for the epoxy type together with the amplitude frequencies from 30–100 dB. The optimized network contained two hidden layers having nine neurons apiece. Here the ultimate load prediction was within 48 lbf for a 9.5 % error. Thus, the back-propagation neural network produced far better results than the SOM/multiple linear regression, probably because of unwanted noise and perhaps nonlinearities in the data.

117 水撃ポンプ内における弁まわりの流れの観察(流体 III,2.学術講演)

117 水撃ポンプ内における弁まわりの流れの観察(流体 III,2.学術講演)

A teaching material which mainly relates the process of inquiry : Using the characteristic of a hydraulic ram pump

A teaching material which mainly relates the process of inquiry : Using the characteristic of a hydraulic ram pump

Modelling and Control of a Hydraulic Actuated Large Scale Manipulator

AbstractThis contribution deals with the modelling and control of an elastic manipulator. The arm is actuated by a hydraulic ram due to the significant weight. The overall goal is to achieve good tracking of the tip, as well as to reject disturbances, which act on the flexible arm. The controller design is based on two approaches. A flatness‐based feedforward control takes care of the tracking behaviour, and a passivity‐based feedback law stabilizes the trajectories and suppresses the elastic vibrations. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Energy Based Control of Hydraulic Actuators in Steel Rolling Mills

This contribution deals with an energy based controller design for hydraulic actuators. Equilibrium thermodynamics is used in order to establish the energy relations for physical systems with mass flow across their boundaries. A double acting hydraulic ram is used as an application example. Further, an energy based controller is derived for this multi-input-multi-output system. Finally, industrial measurements from a steel rolling mill which demonstrate the implemented control law will be presented.

Effect of soil compaction and water content on the resulting forces acting on three seed drill furrow openers

In rainfed semiarid central Spain, seed drills for conventional and minimum tillage are equipped with chisel-type furrow openers. Recently, seed drill manufacturers have introduced new furrow openers designs that are claimed to be effective alternatives to the former opener. Experiments were conducted in a laboratory soil bin containing a loam soil to assess the combined effect of soil compaction and soil water content on the resulting forces and furrow cross-sectional areas of three commercially available seed drill furrow openers. The furrow openers compared were a chisel-type (FO1), a non-winged combine type (FO2) and a modified Suffolk type (FO3). These furrow openers were driven in the soil by a hydraulic ram at a forward speed of 40 mm s −1 and the resulting force reactions were measured by an L type load cell. Five gravimetric water contents (60, 90, 120, 150 and 180 g kg −1), four soil bulk densities (1.1, 1.2, 1.3, 1.4 Mg m −3) and two working depths (50 and 100 mm) were considered in the experiments. The experimental design consisted in a (5×4×2) complete randomised factorial with three replicates for each test. The greater were the bulk density and water content of the soil the greater was the draft force measured in the three furrow openers, but this effect was more apparent at a working depth of 100 mm than at 50 mm. On average FO1 exhibited the lowest draft force followed by FO2 and FO3. In the three furrow openers the vertical force increased with increasing working depth, soil bulk density and soil water content, and its value was greater for FO1 than for FO3 and FO2. Irrespective of the working depth, the furrow cross-sectional area of the three openers increased with soil water content. While such an area was independent of the soil bulk density at a working depth of 50 mm, it decreased with increasing density at 100 mm. Whatever the working depth, the average draft and vertical forces measured with FO1 fitted different quadratic functions of the soil bulk density. In FO2 and FO3, however, the relationship between draft force and soil bulk density was linear at working depth of 50 mm, and quadratic at a depth of 100 mm. The vertical force acting on these two openers was linearly related to soil bulk density at both working depths.

Production of a Hydraulic Ram Pump and its Research on its Characteristic

Production of a Hydraulic Ram Pump and its Research on its Characteristic

Failure of Fluid Dilled Structures Due To High Velocity Fragment Impact

A series of experimental tests have been conducted to study the failure of fluid filled containers caused by high velocity fragment impact. On penetrating the fluid, the fragment generates high pressure shock waves which on reaching the container walls result in rapid loading of the structure. Commonly known as the hydraulic ram effect, experiments have been performed to study the effect in detail for compact steel fragments of a few grammes mass at velocities between 1 km/s and 4 km/s. High-speed photography has been used to record the projectile motion in the fluid, the growth of the cavity behind the projectile and the propagation of the primary shock wave. Shock pressures in the fluid were measured and show that the duration and magnitude of the primary shock wave increase with increasing projectile velocity. A number of techniques for reducing the damage to the structure by alleviating the shock pressure in the fluid have been studied. The most promising of these techniques rely on interaction with the shock wave and increasing the compressibility of the fluid by introducing collapsible baffles into the fluid and by aeration. Dramatic reductions in structural damage have been obtained with modest levels of fluid loss, < 10%. Future work will involve optimisation of these hydraulic ram alleviation techniques for different projectiles, impact velocities and fluid filled structures.