Numerical determination and experimental verification of the optimum autofrettage pressure for a complex aluminium high‐pressure valve to foster crack closure

2020 ◽  
Vol 43 (10) ◽  
pp. 2183-2199
Author(s):  
Christian Repplinger ◽  
Stephan Sellen ◽  
Slawomir Kedziora ◽  
Arno Zürbes ◽  
Thanh Binh Cao ◽  
...  
Keyword(s):  
High Pressure ◽  
Crack Closure ◽  
Experimental Verification ◽  
Numerical Determination ◽  
Autofrettage Pressure

High-pressure experimental verification of rutile-ilmenite oxybarometer: Implications for the redox state of the subduction zone

2017 ◽  
Vol 60 (10) ◽  
pp. 1817-1825 ◽  
Author(s):  
RenBiao Tao ◽  
LiFei Zhang ◽  
Vincenzo Stagno ◽  
Xu Chu ◽  
Xi Liu
Keyword(s):  
High Pressure ◽  
Subduction Zone ◽  
Experimental Verification ◽  
Redox State

scholarly journals Direct Observation of Filling Process and Porosity Prediction in High Pressure Die Casting

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1099 ◽  
Author(s):  
Hanxue Cao ◽  
Chao Shen ◽  
Chengcheng Wang ◽  
Hui Xu ◽  
Juanjuan Zhu
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Flow Visualization ◽  
Flow Pattern ◽  
Experimental Verification ◽  
Die Casting ◽  
Filling Process ◽  
High Pressure Die Casting ◽  
Visualization Experiment ◽  
Pressure Die Casting

Although numerical simulation accuracy makes progress rapidly, it is in an insufficient phase because of complicated phenomena of the filling process and difficulty of experimental verification in high pressure die casting (HPDC), especially in thin-wall complex die-castings. Therefore, in this paper, a flow visualization experiment is conducted, and the porosity at different locations is predicted under three different fast shot velocities. The differences in flow pattern between the actual filling process and the numerical simulation are compared. It shows that the flow visualization experiment can directly observe the actual and real-time filling process and could be an effective experimental verification method for the accuracy of the flow simulation model in HPDC. Moreover, significant differences start to appear in the flow pattern between the actual experiment and the Anycasting solution after the fragment or atomization formation. Finally, the fast shot velocity would determine the position at which the back flow meets the incoming flow. The junction of two streams of fluid would create more porosity than the other location. There is a transition in flow patterns due to drag crisis under high fast shot velocity around two staggered cylinders, which resulted in the porosity relationship also changing from R1 < R3 < R2 (0.88 m/s) to R1 < R2 < R3 (1.59 and 2.34 m/s).

Research on the Best Autofrettage Pressure of Ultra-High Pressure Valve Body

2015 ◽  
Vol 667 ◽  
pp. 524-529
Author(s):  
Xiu Hua Ma
Keyword(s):  
High Pressure ◽  
Simulation Analysis ◽  
Equivalent Stress ◽  
Maximum Pressure ◽  
Working Pressure ◽  
Valve Body ◽  
Ultra High Pressure ◽  
Pressure Discharge ◽  
Maximum Equivalent Stress ◽  
Autofrettage Pressure

This paper takes the ultra-high pressure (103.5MPa) valve body as the research object and adopts the finite element method to perform simulation analysis on the three bearing conditions involved with the valve body, i.e., autofrettage pressure, discharge and working pressure. The simulation shows identical results with the theoretical calculation. The relationship between the maximum equivalent stress and autofrettage pressure during the operation of the valve is obtained from the simulation results; therefore the best autofrettage pressure is determined. When determining the maximum value of autofrettage pressure, the maximum pressure, at which reverse yield does not happen, and the complete yield pressure shall be taken into consideration, with the smaller value of the two taken after comparison and analysis. When the size of the valve body is fixed at certain value, the best autofrettage pressure is not a fixed value, but it varies with the change of working pressure.

Hydraulic Jacking

1971 ◽  
Vol 13 (6) ◽  
pp. 384-396
Author(s):  
E. T. Eliasson
Keyword(s):  
High Pressure ◽  
Approximate Solution ◽  
Analytical Solution ◽  
Finite Length ◽  
Experimental Verification ◽  
Journal Bearing ◽  
Small Diameter ◽  
Load Carrying ◽  
Bearing Design ◽  
Hydraulic Jacking

The trend in modern plain journal bearing design is towards a reduction in the relative bearing width; this results in reduced machine bulk and bearing losses, but has the disadvantage of increased bearing wear, particularly at starting, stopping and the reversal of motion. A method of reducing this wear problem is by means of hydraulic jacking, or the separation of the load carrying surfaces by the introduction of high pressure oil into the clearance space, through suitable feed grooves. The article describes an analytical solution to the problem of hydraulic jacking. The following solutions are presented, giving full performance characteristics. (1) Single- and twin-axial feed grooves, end leakage neglected. (2) Single- and twin-axial feed grooves, concentric journal, finite length bearing (approximate solution). (3) Single- and twin-axial feed holes, concentric journal, small diameter feed holes (approximate solution). Some experimental verification is given for the theory of the axial feed groove arrangement, both the single grooved and the twin grooved arrangement.

Design of Ultra-High Pressure Cylinders Based on Principle of Autofrettage

2011 ◽  
Vol 142 ◽  
pp. 24-27 ◽  
Author(s):  
Yu Xian Zhang ◽  
Fang Yao ◽  
Xiao Shuang Men
Keyword(s):  
High Pressure ◽  
Stress Distribution ◽  
Key Words ◽  
Diameter Ratio ◽  
Cylinder Block ◽  
Outer Diameter ◽  
Elastic Plastic ◽  
Ultra High Pressure ◽  
Improved Design ◽  
Autofrettage Pressure

Through the analysis of stress in ultra high-pressure cylinders, found that its stress distribution is very uneven. In order to use the principle of autofrettage for improving design of the cylinders, first with Faupel-Furbe formula to calculate estimates of diameter ratio, and thus are inner and outer diameter of the cylinder block. Then the cylinder is determined parameter of autofrettage on the cylinder such as the optimum radius of elastic-plastic junction and the optimum autofrettage pressure. Finally, analysis and calculation of stress in improved design cylinder, the results show that the improved design of cylinder have a greater degree of improvement in weight, size and stress distribution of three areas. Key words: autofrettage; ultra-high pressure cylinders; diameter ratio; stress distribution.

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