Hydraulic Tests Research Articles

Fault Classification for Cooling System of Hydraulic Machinery Using AI.

Hydraulic systems are used in all kinds of industries. Mills, manufacturing, robotics, and Ports require the use of Hydraulic Equipment. Many industries prefer to use hydraulic systems due to their numerous advantages over electrical and mechanical systems. Hence, the growth in demand for hydraulic systems has been increasing over time. Due to its vast variety of applications, the faults in hydraulic systems can cause a breakdown. Using Artificial-Intelligence (AI)-based approaches, faults can be classified and predicted to avoid downtime and ensure sustainable operations. This research work proposes a novel approach for the classification of the cooling behavior of a hydraulic test rig. Three fault conditions for the cooling system of the hydraulic test rig were used. The spectrograms were generated using the time series data for three fault conditions. The CNN variant, the Residual Network, was used for the classification of the fault conditions. Various features were extracted from the data including the F-score, precision, accuracy, and recall using a Confusion Matrix. The data contained 43,680 attributes and 2205 instances. After testing, validating, and training, the model accuracy of the ResNet-18 architecture was found to be close to 95%.

Development of a hydraulic pump motor test stand based on mechanical power recovery

Abstract As an important component of the hydraulic system, the performance of the hydraulic pump and motor greatly influences the performance of the whole hydraulic system, so it is necessary to study the hydraulic pump and motor test system. In this paper, the design of the mechanical power recovery hydraulic pump motor test system is completed through theoretical analysis and calculation; and the AMEsim simulation software is used to numerically simulate the test process of the hydraulic pump and motor test system, analyze the system loading method of the test system, recovery efficiency and simulation of typical working conditions; meanwhile, the control strategy of adjusting the single variable motor displacement to control the minimum overflow of the system is simulated and analyzed Simulation analysis is also performed for the control strategy of adjusting the univariate motor displacement to control the minimum overflow. Simulation results show that: the recovery efficiency of the mechanical power recovery hydraulic pump motor test system varies with the size of the overflow; when the system is the minimum overflow value, the optimal recovery efficiency of 75% is achieved, and the recovery performance is improved by 32% compared with other power methods. The mechanical power recovery hydraulic pump motor test system designed in this paper solves the shortcomings of high energy consumption, low recovery efficiency, and small application range of the previous single way of loading; at the same time, based on meeting the function and performance, the hydraulic pump and motor test system are integrated into one system, and the applicability and scalability are significantly improved.

Tensile Strength of Abaca Fiber Reinforced Polymer Composite Fabricated by Press Method: Effect of Fiber Content and Fiber Orientation

The paper reported the study on the tensile strength of polymer composite reinforced with abaca fiber and polyester matrix. The effect of fiber weight content and fiber orientation on the tensile strength of the abaca composite were investigated in the study. The abaca composite panel was fabricated using press method with 3 levels of the fiber weight content (20%, 30% and 40%) and 3 levels of fiber orientation (00, 450 and 900). The tensile specimen was prepared according to ASTM D3039 standard. The tensile test was conducted using MTS Landmark servo hydraulic testing machine with a tensile speed of 2 mm/min. The result of the experiment showed that both of fiber weight content and fiber orientation gave significant effect on the tensile strength of the abaca composite. The highest tensile strength was 61.9 MPa, produced by the abaca composite panel with fiber weight content 30% and fiber orientation 00. According to the standard, the tensile strength has fulfilled the requirements as a non-structural material.

Hydraulic Conductivity, Microstructure, and Compositional Changes of Sand–Bentonite Backfill in Cutoff Walls Exposed to Organic Acids

Leachate, consisting of organic acids such as acetic acid (AA) and oxalic acid (OA), commonly is released into groundwater from municipal solid waste dumps and uncontrolled landfills. Slurry trench cutoff walls commonly are used to contain such contaminated groundwater, thereby protect the surrounding public and the environment. However, no studies have assessed comprehensively the effects of organic acid–laden groundwater exposure on the hydraulic conductivity and microscopic characteristics of sand–bentonite (SB) backfill in the cutoff walls. Several series of free swell, liquid limit, and flexible-wall hydraulic conductivity tests were conducted to quantify the effects of AA and OA exposure on the free swell index of bentonite and hydraulic conductivity and liquid limit of SB backfill. Results showed that the free swell index of bentonite and the liquid limit of SB backfill decreased with increasing concentrations of AA and OA. Exposure to AA yielded a lower free swell index of bentonite and liquid limit of SB backfill than those of OA with the same concentration. Increasing concentrations of AA and OA resulted in an increase in the hydraulic conductivity of SB backfills. Exposure to AA yielded higher hydraulic conductivity of SB backfill than OA with the same concentration. Mechanisms for increased hydraulic conductivity under organic acid exposure were ascertained based on the microstructure and compositional changes quantified by field-emission scanning electron microscopy (FESEM), mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), X-ray fluorescence (XRF), cation exchange capacity (CEC), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FTIR) analyses.

TEORETICAL-EXPERIMENTAL COMPARISON OF THE MODELS OF ADDITIVELY MANUFACTURED SWIRL INJECTORS BASED ON THE HYDRAULIC TESTING RESULTS

Annotation. Recent success in development of the technology stipulated the appearance of advanced additive manufacturing aimed to shift conventional subtractive manufacturing from its position in the engineering field. Thus, for LPRE manufacturing there is an obvious advantage of additive manufacturing in terms of ability to produce single-piece parts with complex geometry must be seriously considered. In the modern world there is a constant competition between complex engineering decisions and cost efficiency of the production on the market of liquid propellant rocket engines. On the one hand, mixing head is one of the most demanding parts of LPRE in terms of designing. On the other hand, the earliest stage of its development starts with the choice of a type of mixing elements to ensure combustion stability, efficiency, and overall production cost [1]. Typically this step requires advanced knowledge in the real characteristics of produced injectors, or extensive experimental study should be carried out otherwise. In this work a problem of determining the characteristics of additively manufactured swirl injectors is considered. Laser Powder Bed Fusion [10] was chosen as a production method using Haynes 230 as a main material. A range of the swirl injectors with varied geometrical parameters was manufactured. Hydraulic testing was carried out in a wide range of Reynolds numbers for determining flow characteristics. Typically, discharge coefficient and spray angle are the desired values to know. Sauter mean diameter and film thickness were not studied due to lack of equipment. Considering a problem of prediction of the main characteristics of the produced injectors, a review on known equations for calculation of the main parameters was performed. Comparative analysis between calculated and experimental data was carried out. Results show that there is severe discrepancy between calculated values of characteristics of injectors and experimentally obtained data for additively manufactured swirl injectors. Even though the conducted study gives a base to form consistent conclusions of the behavior of the obtained characteristics, additional investigation is required.

Experimental definition of lateral stiffness of a pneumatic wheel of the MTZ-82 “Belarus” tractor

BACKGROUND: Due to the excessive vertical and angular vibrations of suspensionless vehicles used in agriculture and road construction that occur during movement, the velocity of their motion is limited, which, in the conditions of a constant traffic flow, reduces the road capacity. Therefore, the search for ways to improve the vibration-isolating properties of wheeled suspensionless vehicles is a relevant issue, the solution of which affects not only on traffic safety and driving comfort, but also on average speed and fuel efficiency.
 AIMS: To determine the lateral stiffness of the pneumatic wheel from the rear axle of the MTZ-82 Belarus tractor at different tire pressures, basing on bench tests.
 METHODS: On the basis of the hydraulic pulsation test rig of the Automatic Units department of the VolgGTU, a special-purpose movable supporting and measuring device was developed and assembled, the feature of which is that 4 rollers with flanges are installed on top of the hydraulic actuator force sensor, a flat rectangular base plate is supported on these rollers and connected with a vertical frame of the rig through a force-measuring device by means of a screw mechanism. The tested wheel is mounted on the base plate, the wheels axle is fixed on a vertically-moving traverse, on top of which weights creating the necessary vertical force are fixed. The test procedure consisted in measuring the lateral force and lateral displacement of the base plate until the tire slip occurred at the following tire pressures: at the recommended pressure of 0.16 MPa and at reduced pressures of 0.12, 0.08 and 0.04 MPa.
 RESULTS: Based on the test results, the elastic characteristic curves of the lateral stiffness of the tested wheel were obtained. These characteristic curves have a regressive form, as their slope significantly decreases with a significant reduce in tire pressure. Thus, when the tire pressure is reduced from 0.16 to 0.12 MPa, there is practically no difference in the obtained values of lateral stiffness, which reaches 112.5 kN/m. After a 2-fold tire pressure reduction, the lateral stiffness decreases by 7%, and after a 4-fold reduction, by 28%. At the same time, the static tire deflection increases from 22 to 32 mm, which significantly increases the contact patch of the tire with the ground.
 CONCLUSIONS: By means of the tests carried out, it is established that tire pressure reduction by 2550% of the recommended value does not have a significant effect on the loss of lateral stiffness of the pneumatic wheel of the rear axle of the MTZ-82 Belarus tractor, which is important to use in order to increase traction and improve ride comfort of wheeled tractors.

Visualization of hydraulic fracture interacting with pre-existing fracture

Hydraulic fracturing is considered the main stimulation method to develop shale gas reservoirs. Due to its strong heterogeneity, the shale gas formation is typically embedded with geological discontinuities such as bedding planes and natural fractures. Many researchers realized that the interaction between natural fractures and hydraulic fractures plays a crucial role in generating a complex fracture network. In this paper, true tri-axial hydraulic fracturing tests were performed on polymethyl methacrylate (PMMA), on which pre-existing fracture was pre-manufactured to simulate natural fracture. A cohesive model has been developed to verify the results of the experimental tests. The key findings demonstrate that the experimental results agreed well with the numerical simulation outcomes where three main interaction modes were observed: crossing; being arrested by opening the pre-existing fracture; being arrested without dilating the pre-existing fracture. Crossing behavior is more likely to occur with the approaching angle, horizontal stress difference, and injection rate increase. Furthermore, the higher flow rate might assist in reactivating the natural fractures where both sides of the pre-existing fractures were reactivated as the injection rate increased from 5 to 20 mL/min. Additionally, hydraulic fractures show a tendency to extend vertically rather than along the direction of maximum horizontal stress when they are first terminated at the interface. This research may contribute to the field application of hydraulic fracturing in shale gas formation.

Engineering Properties of Novel Vertical Cutoff Wall Backfills Composed of Alkali-Activated Slag, Polymer-Amended Bentonite and Sand.

The workability, hydraulic conductivity, and mechanical properties are essential to contaminant containment performance of cementitious backfills in vertical cutoff walls at contaminated sites. This study aims to investigate the engineering properties of a novel vertical cutoff wall backfill composed of reactive magnesia (MgO)-activated ground granulated blast furnace slag (GGBS), sodium-activated calcium bentonite amended with polyacrylamide cellulose (PAC), and clean sand (referred to as MSBS-PAC). Backfills composed of MgO-activated GGBS, sodium-activated calcium bentonite, and clean sand (referred to as MSBS) were also tested for comparison purposes. A series of tests were conducted which included slump test, flexible-wall hydraulic conductivity test, and unconfined compression test. The pore size distributions of two types of backfills were investigated via the nuclear magnetic resonance (NMR) technique. The results showed the moisture content corresponding to the target slump height was higher for MSBS-PAC backfill than that for MSBS backfill. The MSBS-PAC backfill possessed lower pH, dry density, and higher void ratio at different standard curing times as compared to MSBS backfill. The unconfined compressive strength and strain at failure of the MSBS-PAC backfill were noticeable lower than those of the MSBS backfill. In contrast, the hydraulic conductivity of MSBS-PAC backfill was approximately one order of magnitude lower than that of the MSBS backfill, which was less than 10-9 m/s after 28-day and 90-day curing. Lower hydraulic conductivity of MSBS-PAC backfill was attributed to the improvement of pore structure and pore fluid environment by PAC amendment.

Utilization of waste marine dredged clay in preparing controlled low strength materials with polycarboxylate superplasticizer and ground granulated blast furnace slag

To solve the disposal of massive waste marine dredged clay (MDC), this study proposes a new method of utilizing it in preparing controlled low strength materials (CLSM). In which the polycarboxylate superplasticizer (PCE) and ground granulated blast furnace slag (GGBS) were used to break the current dilemma that the flowability and strength can only be guaranteed by simultaneously increasing the water content and cement content. The flowability, strength and hydration conductivity were investigated through a series of flow tests, unconfined compression strength (UCS) tests and hydraulic conductivity tests, the microstructure and mineralogical tests were performed to reveal the mechanism of PCE and GGBS accordingly. The results show that GGBS provides more active silicon and active aluminum to promote the generation of hydrated calcium silicate (CSH) and hydrated calcium silicate aluminate (CASH), leading to a higher strength and impermeability of CLSM with GGBS than CLSM with pure ordinary Portland cement (OPC). PCE disperses both MDC and PCE in the CLSM and improves flowability through electrostatic force and steric hindrance, contributing to a rapid increase of flowability under 0.4% of PCE content. Under the collaborative effects of PCE and GGBS, MDC-based CLSM achieves higher strength and flowability at relatively lower cement content and water content, which not only solves the contradiction between flowability and strength of conventional CLSM, but also offers scientific references to the broad application of solid wastes (MDC and GGBS) in CLSM preparation, which promotes the sustainable development of green construction materials significantly.

Large-Scale Hydraulic Performance Testing of a Geotextile Mechanically Stabilized Earth (MSE) Wall Constructed with Recycled Concrete Aggregate Backfill

Abstract Constructing geosynthetic mechanically stabilized earth walls with recycled backfill materials reduces environmental impacts and financial cost compared with their gravity wall counterparts. While a large database of column-scale tests to evaluate the hydraulic performance of recycled backfill materials exists in the literature, clogging potential under multidimensional flow conditions has not been examined. A large-scale reinforced soil wall and a complementary column test constructed with recycled concrete aggregate (RCA) and closely-spaced woven geotextile reinforcement were tested to examine chemical and physical clogging under wetting-drying cycles. Internal moisture migration and the evolving chemical signature of leachate were measured. Geotextile samples were exhumed after the tests and analyzed to evaluate chemical (tufa formation) and physical (fines migration) clogging. The complementary multidimensional and column experiments afford direct comparison of outflow chemistry and effects on geotextile permittivity. Geotextiles in the large-scale wall and column tests did not show any evidence of chemical or physical clogging and no evidence of positive pore pressures was detected. Outflow leachate from the wall test had higher total dissolved solids values and higher concentrations of Ca and SO4 in comparison to the column test. The pH of leachate from the column test is initially lower than from the wall, but results become similar (pH ∼12) at test completion. Leachate from both tests is supersaturated with tufa minerals. Differences in leachate characteristics of the two tests can be attributed to the initial moisture content of the backfill, larger quantity of RCA material in the large-scale wall, and the multidimensional flow characteristics of the large-scale wall. Results validate previous observations from column tests in terms of moisture retention and chemical response when flow conditions are multidimensional. Maintaining a free-draining backfill under conditions that could promote clogging (closely-spaced woven geotextile reinforcement layers) gives further confidence in using RCA as backfill under these conditions.

Studying the Behavior of Asphalt Stabilized Gepseous Soil for Earth Embankment Model

The study presents the test results of stabilizing gypseous soil embankment obtained fromAl- Faluja university Campus at Al-Ramady province. The laboratory investigation was dividedinto three phases, The physical and chemical properties, the optimum liquid asphalt (emulsion)requirements (which are manufactured in Iraq) were determined by using one dimensionalunconfined compression strength test.in the first phase , The optimum fluid content was 11%(6% of emulsion with 5% water content).. At phase two, the effect of Aeration technique wasinvestigated using both direct shear and permeability test. At phase three for the case of staticload , the pure soil embankment model under dry test condition was investigated, The testingprogram included the determination of the unconfined compressive strength, direct shearstrength, constant head permeability test, and one dimensional consolidation test for pure andasphalt stabilized gypseous soil. Testing was carried out in dry and absorbed conditions, themaximum pressure that can be supported before failure (ultimate sustained pressure) is 0.76MPa with vertical settlement (0.21 mm) . However, For the pure soil embankment model underabsorbed condition it was found that the maximum pressure before failure (ultimate sustainedpressure) is 0.3 MPa with vertical settlement (12 mm), Which reflects the reduction in bearingcapacity by (61%). Compression was made for absorbed stabilized soil and un-absorbed soiltested under hydraulic conductivity test for seven days, the results showed that a very lowmargin deffeneces in maximum pressure resistance and settlement were obtained (4.38 MPa ,0.11mm ) and (4.11MPa , 0.12mm).

Induced hydraulic fractures in underground block caving mines using an extended finite element method

Block caving has become an attractive underground rock mining method that requires effective preconditioning of the orebody to initiate the progressive rock collapse by its weight. Hydraulic fracturing is commonly used in cave mining as a preconditioning method to induce artificial fractures in the orebody rock mass. This paper presents the numerical model of hydraulic fracture propagation in underground caving mines. An extended finite element method based on phantom nodes is adopted to simulate the propagation of multiple fractures along arbitrary paths. A poroelastic constitutive model governs the behavior of orebody rock mass, while a cohesive zone model controls the hydraulic fracture propagation. The adopted method is validated against analytical solutions for penny-shaped hydraulic fracture. The stress shadowing effect on hydraulic fracturing is investigated using representative rock properties from the “El Teniente mine”, obtained by calibrating a hydraulic fracturing field test. Several analyses of multiple hydraulic fractures considering a sequential fracturing scheme are simulated to investigate the influence of in-situ stresses, fracture spacing, injection flow rate, and Young's modulus and permeability of the matrix. The numerical results show that small fracture spacing, in-situ stress, and rock permeability locally change the principal stress magnitude, resulting in a more extensive fracture propagation. Also, the injection of new fractures induces stress shadows that reinitiate the propagation of the previous ones. This behavior is reduced by increasing the fracture spacing and rock permeability. Finally, this paper provides insights into the main parameters that affect fracture extension, which can be used to optimize the preconditioning process of underground block caving mines.

Measurement of displacement and top beam attitude angle of advanced hydraulic support based on visual detection

We constructed an advanced hydraulic support test bench and proposed a visual detection-based approach for measuring the displacement and attitude angle of the advanced hydraulic support. Firstly, our methodology involved using a binocular camera for image acquisition and stereo rectification of the advanced hydraulic support. Then, we employed the ORB algorithm to detect feature points and the SGBM matching algorithm to determine the disparity value. Finally, the attitude angle solution algorithm and the triangulation method are written to calculate the support displacement and the top beam attitude angle. Results showed that the advanced hydraulic support had an average absolute error of 8 mm in displacement measurement and 0.4° in attitude angle measurement, meeting the accuracy requirements for fully mechanized mining face operations.

A novel hydraulic bulge test in hot forming conditions

A novel hydraulic bulge test device was developed to evaluate high temperature biaxial stress–strain curves of quenchable boron steel sheets. The work mainly focuses on the resistance heating designed to assure a homogeneous temperature field in the dome area of the circular blank where the hydraulic pressure will be applied. The practical hot stamping conditions, including the heating and cooling steps, were reproduced to perform hydraulic bulge tests on the Usibor ®1500P steel for a temperature range between 700 to 900 °C, after an austenization step at 900 °C. Stress–strain curves were obtained from these expansion tests using the data extracted with a laser profilometer, due to the difficulties associated with the use of Digital Image Correlation at such high temperatures. Although the profilometer is a compromise solution, the comparisons between tensile and biaxial stress–strain results enable to verify the feasibility of the new device for the evaluation of the stress–strain curves at a high temperature in a biaxial state. The results point-out that, besides the difficulties with the acquisition of the strain fields and in the strain-rate control, there are also challenges in the interpretation of the metallurgical evolutions that can occur during the tests, which can affect the biaxial flow curves.

Оценка изменения безопасных расстояний при нарушениях регламента испытаний газопроводов

Accidents occurring during the process of gas pipelines testing are characterized by the impossibility of the occurrence of thermal radiation of jet flames and fire in the pit-damaging factors dominating the operation stage of the facility. In addition, what is happening cannot be accompanied by the baric effect of chemical explosions. However, taking into account the significant increase in pressure in the gas pipeline during pneumatic tests, such damaging factors of the accident as the scattering of fragments, the pressure effect of a high-speed jet and the baric effect of the primary shock wave are amplified. The issue of ensuring the safety of personnel present near the test site becomes relevant. As a result, the need occurs to determine precisely the safe distances to the gas pipeline. Protective zones for the population are also established based on the identified safe distances. Within the framework of the risk-oriented approach, the procedure for determining safe distances is reduced to calculating the distances at which damaging factors lose their damaging properties. When assigning protective zones, it is required to consider the possibility of changing the indicator under consideration, due to probable errors of personnel in the preparation and conduct of tests. Even non-critical miscalculations can significantly affect the determination of a safe distance. The article presents an assessment of the relative values of safe distances, taking into account possible violations of the regulations regarding backfilling and filling with water or air, during hydraulic or pneumatic tests of gas pipelines. Relative values of safe distances are also established in terms of the scattering of fragments and the impact of an air shock wave of a physical explosion on people and building objects.

Hydraulic Conductivity Characteristics of Iron-Ore Tailings–Bentonite Mixtures Exposed to Landfill Leachate

Landfill liner materials are required to provide reliable hydraulic performance for very long times after construction, and at least for the design lifespan of the facility. To meet this objective, liner systems must retain their low hydraulic conductivity over their service lives. In this paper, we report on the durability aspects of iron-ore tailings (IOT)–bentonite mixtures in extended hydraulic conductivity experiments. The hydraulic conductivity tests were conducted on mixtures containing 20%, 25%, 30%, 35%, and 40% bentonite, compacted at 2% wet of optimum by the British standard light (BSL) effort, and permeated with municipal solid waste (MSW) landfill leachate (electrical conductivity = 25.60 mS/m, pH = 7.94) with or without prehydration for a duration of 120 days. Under these influences, permeation with leachate showed no detrimental effect on mixtures with 25% and 30% bentonite, but was rather beneficial in reducing the hydraulic conductivity (k) values of the two mixtures at the end of testing by two orders of magnitude to 4.19 × 10−8 and 9.25 × 10−9 cm/s for the prehydrated specimens and 2.4 × 10−8 and 9.9 × 10−9 cm/s for the nonprehydrated specimens. For mixtures containing 20%, 35%, and 40% bentonite, k values representing a 1.6 times decrease from the average were recorded for both the prehydrated and nonprehydrated conditions at the end of testing. Further analysis showed that prehydration had a slightly substantial effect on those specimens containing 20%, 35%, and 40% bentonite, whereas it had a minor effect, if any, on mixtures with 25% and 30% bentonite. In terms of durability, only mixtures containing 25% and 30% bentonite that consistently maintained low k values up to the end of testing are projected to be effective as liner materials in the construction of geological repositories for MSW. Regarding the hydraulic conductivity characteristics of the mixtures upon exposure to the combined effects of leachate and the elevated temperatures expected in landfill conditions, all mixtures maintained relatively good hydraulic performance, exhibiting a decrease in hydraulic conductivity with time.

Degradation of Hydraulic System due to Wear Particles or Medium Test Dust

Contamination in hydraulic systems is the cause of 70% of failures. This study highlights the performance degradation caused by solid particle contamination of hydraulic components: hydraulic gear pump, 4/3 valve, and orbital motor. Experimental durability tests of components with wear particles and test dust are used to investigate the effects of accelerated wear caused by these two types of contaminants. Results show that oil contaminated with wear particles reduces the volumetric efficiency of the gear pump by 18% and the hydraulic valve by only 0.8%, while oil contaminated with test dust reduces the efficiency of the pump by 76% and the hydraulic valve by 0.9%. This research provides insights for accelerating hydraulic component testing to improve system reliability and longevity.

Electromagnetic Waves’ Impact on Hydraulic Conductivity of Granular Soils

Electromagnetic (EM) waves, traditionally used for purposes such as geophysical characterization, impact properties to be measured. This paper describes the effects of radio frequency (RF) waves on the hydraulic conductivity of glass beads and natural sand. A series of tests was conducted using a customized, rigid-wall, cylindrical permeameter inside a resonant cavity made of Plexiglas covered with electrically conductive transparent films. Constant-head ASTM-D2434 tests were performed to measure the samples’ hydraulic conductivity. RF stimulation was performed using a magnetically coupled loop antenna at various frequencies and input RF-power levels. The hydraulic conductivity of both natural sand and glass-bead samples increased with RF stimulation. Furthermore, the measurement of the electric field component of RF waves was also performed to illustrate the pattern of the electric field, as well as evaluate RF’s impact on the hydraulic conductivity tests. The electric field was numerically simulated and validated against experimentally measured electric fields. A finite-difference numerical model was developed in MATLAB to analyze the seepage flow, which was then validated against the experimental results. An optimization scheme was then used to develop a governing equation for RF’s impact on hydraulic conductivity.

Numerical simulation of springback and twisting of stamped thin U-shaped copper alloy sheets with a change of the blank alignment

An experimental database of springback and twisting of U-shaped elongated structures is available from a previous study. The materials are copper alloys: pure Cu, CuBe2, and CuFe2P, provided in thin sheets of thickness around 0.1 mm. After deep-drawing of rectangular blanks, which can be aligned with the tools or slightly misaligned, and tool withdrawal, the U-shaped structure exhibits an opening of the section (2D springback) and twisting (3D springback). Characteristic features of the deformed geometry are significantly different for the three alloys. This study is directed to understand the origin of that difference with a numerical simulation of the process. The mechanical behaviour of the materials was investigated in tension and hydraulic bulge test, out of comparison’s sake and to derive the hardening law over a strain range representative of the process. Finite element simulations are performed using the von Mises criterion coupled with isotropic hardening, to compare the predicted forming load and springback parameters with experimental values.

Force Characteristics and Mechanical Topology Optimization of Hydraulic Machine Structures: Statics and Dynamics

In this paper, the design requirements of the hydraulic testing machine are based on the actual force conditions. Static and dynamic performance analyses of the stressed components of the hydraulic machine are carried out and the mechanical topology is optimized. Combining the static and dynamic objective functions of the structure, a fast variable density topology method is proposed, thus improving the optimization efficiency. After setting the positions of the optimized and non-optimized regions. It can be found that the optimized mechanical performance is more superior as the number of iterations increases. The results show that the stress in the strut is 175.75 MPa and the maximum stress in the upper beam structure is 43.708 MPa. The first sixth order frequency is much higher than the operating frequency of 3 Hz. The final results of the mechanical topology optimization analysis show. The optimized structure of the upper, middle and lower crossbeams resulted in a mass reduction of 38%, 36% and 5.57%. The maximum stresses in the upper and middle crossbeams were reduced by 10.33%, 8.3% and 51.8%, respectively. The deformation was reduced by 6.14% at the fastest time; the inherent frequency of the first 3 orders was increased to achieve light weight. The overall mechanical properties became better after optimization, and the dynamic and static stability of the frame was improved. Translated with www.DeepL.com/Translator (free version)