A High Pressure-Short Time Shear Strength Analyzer for Lubricants

1985 ◽  
Vol 107 (2) ◽  
pp. 220-223 ◽  
Author(s):  
B. Jacobson
Keyword(s):  
High Pressure ◽  
Shear Strength ◽  
High Speed ◽  
Maximum Pressure ◽  
Strength Increase ◽  
Transient Pressure ◽  
Static Tests ◽  
Speed Test ◽  
Short Time ◽  
The Impact

High pressure rheology of lubricants under transient pressure and shear stress loads is studied experimentally. The total compression time is about 140 μs and the maximum pressure during the impact time is 5.5 GPa. The results from this high speed test apparatus agree well with static tests of the shear strength increase with pressure up to 2.2 GPa.

Experimental investigation of the quasi-static and impact tests on the energy absorption characteristics of coupler rubber buffers used in railway vehicles

2018 ◽  
Vol 233 (9) ◽  
pp. 937-950 ◽  
Author(s):  
Shuguang Yao ◽  
Zhixiang Li ◽  
Wen Ma ◽  
Ping Xu ◽  
Quanwei Che
Keyword(s):  
Energy Absorption ◽  
Impact Velocity ◽  
High Speed ◽  
Compression Tests ◽  
Static Compression ◽  
Static Tests ◽  
Impact Tests ◽  
High Speed Trains ◽  
The Impact ◽  
Absorption Characteristics

Coupler rubber buffers are widely used in high-speed trains, to dissipate the impact energy between vehicles. The rubber buffer consists of two groups of rubbers, which are pre-compressed and then installed into the frame body. This paper specifically focuses on the energy absorption characteristics of the rubber buffers. Firstly, quasi-static compression tests were carried out for one and three pairs of rubber sheets, and the relationship between the energy absorption responses, i.e. Eabn  =  n ×  Eab1, Edissn =  n ×  Ediss1, and Ean =  Ea1, was obtained. Next, a series of quasi-static tests were performed for one pair of rubber sheet to investigate the energy absorption performance with different compression ratios of the rubber buffers. Then, impact tests with five impact velocities were conducted, and the coupler knuckle was destroyed when the impact velocity was 10.807 km/h. The results of the impact tests showed that with the increase of the impact velocity, the Eab, Ediss, and Ea of the rear buffer increased significantly, but the three responses of the front buffer did not increase much. Finally, the results of the impact tests and quasi-static tests were contrastively analyzed, which showed that with the increase of the stroke, the values of Eab, Ediss, and Ea increased. However, the increasing rates of the impact tests were higher than that of the quasi-static tests. The maximum value of Ea was 68.76% in the impact tests, which was relatively a high value for the vehicle coupler buffer. The energy capacity of the rear buffer for dynamic loading was determined as 22.98 kJ.

scholarly journals Flow Pressure Behavior Downstream of Ski Jumps

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 168 ◽  
Author(s):  
Agostino Lauria ◽  
Giancarlo Alfonsi ◽  
Ali Tafarojnoruz
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Dynamic Pressure ◽  
Pressure Head ◽  
Navier Stokes ◽  
Maximum Pressure ◽  
Navier Stokes Equations ◽  
Free Jet ◽  
Jet Characteristics ◽  
The Impact

Ski jump spillways are frequently implemented to dissipate energy from high-speed flows. The general feature of this structure is to transform the spillway flow into a free jet up to a location where the impact of the jet creates a plunge pool, representing an area for potential erosion phenomena. In the present investigation, several tests with different ski jump bucket angles are executed numerically by means of the OpenFOAM® digital library, taking advantage of the Reynolds-averaged Navier–Stokes equations (RANS) approach. The results are compared to those obtained experimentally by other authors as related to the jet length and shape, obtaining physical insights into the jet characteristics. Particular attention is given to the maximum pressure head at the tailwater. Simple equations are proposed to predict the maximum dynamic pressure head acting on the tailwater, as dependent upon the Froude number, and the maximum pressure head on the bucket. Results of this study provide useful suggestions for the design of ski jump spillways in dam construction.

scholarly journals Experimental and Numerical Impact Analysis of Automotive Bumper Brackets Made of 2D Triaxially Braided CFRP Composites

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3554
Author(s):  
Robert Böhm ◽  
Andreas Hornig ◽  
Tony Weber ◽  
Bernd Grüber ◽  
Maik Gude
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Damage Model ◽  
Drop Tower ◽  
Structural Deformation ◽  
Impact Behavior ◽  
Speed Test ◽  
Damage Models ◽  
The Impact ◽  
Carbon Fiber Epoxy

The impact behavior of carbon fiber epoxy bumper brackets reinforced with 2D biaxial and 2D triaxial braids was experimentally and numerically analyzed. For this purpose, a phenomenological damage model was modified and implemented as a user material in ABAQUS. It was hypothesized that all input parameters could be determined from a suitable high-speed test program. Therefore, novel impact test device was designed, developed and integrated into a drop tower. Drop tower tests with different impactor masses and impact velocities at different bumper bracket configurations were conducted to compare the numerically predicted deformation and damage behavior with experimental evidence. Good correlations between simulations and tests were found, both for the global structural deformation, including fracture, and local damage entities in the impact zone. It was proven that the developed phenomenological damage models can be fully applied for present-day industrial problems.

Loading Rate Effect Investigation of Through-Hole-Mounted Solder Joints

2005 ◽  
Author(s):  
Frank Z. Liang ◽  
Larry M. Palanuk ◽  
Mike Gabriel
Keyword(s):  
Solder Joint ◽  
High Speed ◽  
Loading Rate ◽  
High Loading ◽  
Static Tests ◽  
Loading Rates ◽  
Wide Range ◽  
Load To Failure ◽  
The Impact ◽  
Through Hole

This paper presents two simple and unique tests to extract shock-level loading limits for eutectic and lead free solders. A wide range of loading rates, from quasi-static to high speed, was applied to a through-hole-mounted anchor assembly test coupon. The high speed shock tests were conducted on a drop shock table where the impacting velocities were derived through table input adjustments. The quasi-static tests were done using controlled hydraulic linear actuator with a load cell. As would be assumed, the dynamic load to cause solder joint failure was found to increase with higher loading rate. However, at such a high loading rate range, the impact velocity did not change the load to failure. This study leads to an interesting hypothesis that at high loading rates, the solder joint strain rate may not see a significant change as observed at low rates.

Experimentation and Research of Three-Phase Switching Synchronous Operation of Novel High Speed Switch Gear

2012 ◽  
Vol 621 ◽  
pp. 246-249 ◽  
Author(s):  
En Yuan Dong ◽  
Jin Hu Zhao ◽  
Ying Hua Bi ◽  
Yong Xing Wang ◽  
Xiong Ying Duan
Keyword(s):  
Solid State ◽  
High Speed ◽  
Phase Switching ◽  
Actuation Time ◽  
Repulsion Force ◽  
Thyristor Switch ◽  
Three Phase ◽  
Synchronous Operation ◽  
Short Time ◽  
The Impact

This paper has proposed a novel high speed switch gear (NHSSG) whose contacts could detach quickly; it exploits the principle of the repulsion force generated by eddy effect. The NHSSG is mainly used in the hybrid switch gear (HSG) to cut off the fault circuit cooperate with the solid state thyristor switch gear (SSTSG) in a short time, so it is important for the NHSSG to motion at a certain time. Consequently, a lot of experiments have been done in different aspects to find out the impact extent of the six factors to the actuation time of the NHSSG, and the three-phase switching synchronous operation (TPSSO) experiments have been done based on the result of the analysis, and the accurate three-phase switching synchronous operation was obtained at last.

A discussion on deformation of solids by the impact of liquids, and its relation to rain damage in aircraft and missiles, to blade erosion in steam turbines, and to cavitation erosion - Some aspects of rock cutting by high speed water jets

1966 ◽  
Vol 260 (1110) ◽  
pp. 295-310 ◽  
Keyword(s):  
Pressure Distribution ◽  
High Speed ◽  
Frictional Heating ◽  
Water Jet ◽  
Short Exposure ◽  
Maximum Pressure ◽  
Steam Turbines ◽  
Target Plate ◽  
Water Jets ◽  
The Impact

When rocks are cut in coal mines by steel picks, frictional heating sometimes causes ignition of methane; high speed water jets may provide a method of cutting which is free from this hazard. A high speed water jet emerging from a nozzle slows down with increasing distance from the nozzle and breaks up into water drops. Studies were made of the behaviour of water jets: in most of the experiments the jets were produced by pressures of 600 atm., but some results are given of experiments at pressures up to 5000 atm. The jets were examined by short exposure optical photography with several different methods of illumination (parallel transmitted, diffuse, and schlieren) and by X-ray photography. In order to find out how the jet velocity decays with distance from a nozzle, and to compare nozzle designs, a target plate containing a hole smaller than the jet diameter was placed so that the jet impinged at right angles on to it, and the target plate was moved until the maximum pressure at the hole was found: this was measured for different distances from the nozzle. Nozzle shapes suggested in literature for minimizing jet dispersion were studied and an empirical investigation of a variety of nozzle shapes was carried out. Several nozzle shapes were found which gave good results, i.e. the maximum pressure on the target plate was half the pump pressure at a distance of about 350 nozzle diameters. In many cutting applications the first stage in the process would be the impingement of a water jet on a surface at right angles. The initial cutting would depend upon the stress distribution within the target, which in turn would depend upon the pressure distribution produced by the water jet on the surface. A theory is given of the pressure distribution on the target plate, which predicts that the pressure will fall to zero at about 2.6 jet radii: this was found to be in good agreement with experiments. Preliminary studies were made of the penetration of several types of rock by water jets of velocities up to about 1000 m/s (pressures about 5000 atm). It was found that a 1 mm diameter jet drills a cylindrical hole about 5 mm in diameter. The pressure that the water jet produces at the bottom of such holes was measured and shown to fall off to about one-tenth of the nozzle pressure at a hole depth of about 4 cm.

Study on Vehicle Hook Buffer Mechanism Based on Sequential Image Analysis

2013 ◽  
Vol 365-366 ◽  
pp. 482-485
Author(s):  
Rui Li ◽  
Ping Xu ◽  
Yuan Mu Zhong ◽  
Long Xi Liu
Keyword(s):  
Image Analysis ◽  
Template Matching ◽  
High Speed ◽  
Feature Recognition ◽  
Energy Change ◽  
Sequential Image ◽  
Energy Absorbing ◽  
Sequential Images ◽  
Short Time ◽  
The Impact

As the impact process of train energy absorbing components occurs in a short time, high-speed cameras are used to record it and the amount of deformation and energy change of the energy absorbing components can be obtained by analyzing sequential images. The method of sequential images analysis presented is based on feature recognition of mark points by template matching method. In addition to this, error introduced by the camera positions is corrected to obtain more exact results. During the process of collision, the amount of its deformation is 52mm and its energy change is 2.69KJ when using the sequential image analysis.

scholarly journals Experimental Study on Submerged High-Pressure Jet and Parameter Optimization for Cavitation Peening

Mechanika ◽  
2020 ◽  
Vol 26 (4) ◽  
pp. 346-353
Author(s):  
Yongfei YANG ◽  
Wei LI ◽  
Weidong SHI ◽  
Chuan WANG ◽  
Wenquan ZHANG
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Surface Profile ◽  
304 Stainless Steel ◽  
Nozzle Geometry ◽  
High Speed Photography ◽  
Sem Images ◽  
Before And After ◽  
The Impact ◽  
Divergent Angle

To increase the performance of high pressure submerged cavitation jet that has been used for cavitation peening, the effect of stand-off distance and the nozzle geometry on the impact capacity is investigated and optimized. High speed photography of the cavitation bubble clouds taken to reveal the unsteady characteristics of the cavitating jet. The impact ability of the jet with different nozzles and standoff distance is tested using Al 1060 at first, and the optimized jet is used then for cavitation peening on 304 stainless steel. The surface profile as well as the grain structures before and after peening using different nozzles are observed from SEM images. It is found that, the divergent angle of the nozzle has a great effect on the impact capability of the submerged high-pressure jet, which is important for improving the peening efficiency. In the nozzles with divergent angle 40°, 60° and 80°, the 60° nozzle shows the best performance. After peening, grain cells under the metal surface are changed and a twin layer is formed. The current research reveals the transient characteristics of the submerged cavitation jet and main factors that affect its impact rate, which provides guide for the nozzle design and application for the high-pressure cavitation jet peening.

scholarly journals Influence of air shock wave on shelter

2020 ◽  
pp. 133-144
Author(s):  
Volodymyr Kotsiuruba ◽  
Ivan Datsenko ◽  
Volodymyr Dachkovsky ◽  
Ruslan Cherevko ◽  
Vasyl Polyulyak ◽  
...  
Keyword(s):  
Shock Wave ◽  
Stokes Equations ◽  
Experimental Studies ◽  
Navier Stokes ◽  
Maximum Pressure ◽  
Navier Stokes Equations ◽  
Pressure Time ◽  
Protective Structures ◽  
Short Time ◽  
The Impact

In modern conditions, sheltering people in protective structures, as a way of protection from dangers, in combination with evacuation from the affected areas (pollution) and the use of personal protective equipment, increases the reliability of public protection. In conditions when evacuation measures from cities can be complicated in a short time, protection of the population in shelters becomes the only possible and effective. Therefore, an important task is to study the impact of loads caused by the explosion of various munitions, substantiate recommendations for improving the protective properties of the shelter and the choice of their location. The most common issues are considered in the article that arise during the arrangement of shelter in buildings and outside them. Based on experimental studies, Taylor's formula and the system of non-stationary Navier-Stokes equations for gas, it’s conducted an analysis of the influence of external and internal factors on the possible nature of the dynamic load from the shock wave on buildings, structures and structural elements in which shelters are located. The results of studies of the parameters of dynamic loads showed that if the storage facilities are located in the basements of buildings, their stability is characterized by three parameters: maximum pressure, time to increase the load to maximum and effective time. The parameters of the loads and the law of their change over the time depend on the location of the structure relative to the surface of the earth and the building, the force of the explosion and the distance to the center of the explosion.

Application of Acoustic Emission for High-Pressure Short Time Solidification of Traction Fluids

2005 ◽  
Author(s):  
Nobuyoshi Ohno ◽  
Wataru Tokunaga
Keyword(s):  
High Pressure ◽  
Acoustic Emission ◽  
Dynamic Condition ◽  
Static Condition ◽  
Lubricating Oil ◽  
Rolling Bearings ◽  
Traction Fluids ◽  
Dynamic High Pressure ◽  
Short Time ◽  
The Impact

The lubricating oils solidify at quasi-static high-pressure as the amorphous or glassy solids are verified by a number of studies. However, solidification of lubricating oil under the dynamic condition as the rolling bearings and the traction CVT is not clear. The high-pressure short time solidification of traction fluids is examined by the analysis of dent after the impact tests and AE analysis under impact loads. The intensity of each impact collision is measured by means of an acoustic emission (AE) sensor. The dimensionless AE r.m.s value is investigated by based on phase diagram of testing oils. It was recognized the solidification of oil under the dynamic high-pressure condition almost corresponded to the static condition.

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