scholarly journals An Investigation Into the Effect of Pre-bending on the Tube Hydro-forging Technology

2021 ◽  
Author(s):  
Caiyuan Lin ◽  
Guan-Nan Chu ◽  
Lei Sun
Keyword(s):  
Internal Pressure ◽  
Pressure Difference ◽  
Cold Work ◽  
Hoop Strain ◽  
Cross Sectional ◽  
Advanced Method ◽  
Double Curvature ◽  
Straight Wall ◽  
Bending Radius ◽  
Tubular Component

Abstract Tube hydro-forging (THFG) combining with the pre-bending is an advanced method to manufacture the complex cross-sectional tubular component with curved axis. However, the effect of pre-bending on the subsequent THFG, especially on the critical internal pressure required to inhibit wrinkling, has not been clarified yet. Therefore, this paper makes a detailed study on it. At first, based on the energy method, the change rule between the critical internal pressure and the hoop strain was established when pre-bending was considered. Subsequently, the mechanics condition difference between single and double curvature differential segment during THFG was analyzed. Via the plastic theory, the distribution of hoop strain could be obtained. Mainly due to the uneven distribution of thickness and cold work-hardening caused by pre-bending, the maximum hoop strain at the outer straight-wall was greater than that at the inner straight-wall during THFG. Substituting the maximum hoop strain at the outer/inner straight-wall into the change rule, then their mathematical model of the critical internal pressure to restrain the wrinkling could be solved respectively. Finally, the critical internal pressure considering pre-bending was determined by that of outer straight-wall, and its value was always greater than the critical internal pressure without considering pre-bending under the same punch stroke. With the increase of bending radius, the critical internal pressure difference between considering and not considering pre-bending also increases. When the bending radius was 250 mm, the critical internal pressure difference was 33%, while it increased to 74% as the bending radius reduced to 100 mm, all of which were verified by experiment. The effect of friction coefficient on the critical internal pressure was also studied. In conclusion, this work provided a new and more accurate prediction model of critical internal pressure to guide practical production for when existing the pre-bending.

Optimal Design Study on the Radian and Length of the Guide Plates for the Pipeline Elbow

2012 ◽  
Vol 426 ◽  
pp. 112-117
Author(s):  
Lan Ying Wu ◽  
Yan Lin Wang ◽  
Yong Wei
Keyword(s):  
Optimal Design ◽  
Pressure Difference ◽  
Total Pressure ◽  
Piping System ◽  
Cross Sectional ◽  
Obvious Effect ◽  
Structural Style ◽  
Guide Plate ◽  
Bending Radius ◽  
The Cross

Pipeline elbows are extensively applied in the liquid-conveying piping system, which vibration and noise control are always difficult and critical. The structural style of the guide plates for the liquid-conveying pipe noise eliminating elbow is numerical calculated in this paper, then we find that the fluid liquidity in the liquid-conveying pipe elbow is improved very well by the cross-sectional bending radian and export length of the guide plates, and the two parameters are also optimal designed. The calculated results show that the total pressure difference in the liquid-conveying pipeline elbow decreases first and then increases with the cross-sectional bending radius of the guide plate increases; The total pressure difference decreases first and then increases with the export length of the guide plate increases; When the guide plates according to the gold ratio arrangement, the number, the cross-sectional bending radius and the length are 2, 200 mm and 40 mm respectively, we obtain the total pressure difference is 10707.87 Pa in the liquid-conveying pipeline elbow, comparing it to the result of the original program, it decreases 38.58%, so the internal flow field is improved better, the optimal design has a very obvious effect.

INTERARM SYSTOLIC BLOOD PRESSURE DIFFERENCE IS ASSOCIATED WITH A HIGH PREVALENCE OF CARDIO VASCULAR DISEASES- A CROSS-SECTIONAL STUDY IN POLICE WORKER

2020 ◽  
Vol 4 (11) ◽  
Author(s):  
Somesh Raju ◽  
Rina Kumari ◽  
Sunita Tiwari ◽  
NS Verma
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Blood Sugar ◽  
Pressure Difference ◽  
Systolic Pressure ◽  
Working Environment ◽  
Vascular Events ◽  
Cross Sectional ◽  
Blood Pressure Difference ◽  
High Prevalence

Background: Interarm systolic blood pressure difference more than 10 mm of Hg is predictor of cardiovascular and metabolic risk. Despite of sufficient physical activity there is high prevalence of obesity in police personal because of stressful working environment. No studies have addressed the significance of interarm pressure difference among them. Therefore, the present study conducted to access the relation of interarm blood pressure difference with obesity in police personnel. Aims and Objective: To estimate the interarm pressure difference in police personal to see its association with their obesity. Material and Method: This cross-sectional observational study done on 245 police workers in PAC, Sitapur, India. Subjects having more than ten years of working experience were included in study. Anthropometric measurements of subject recorded by following standard protocol. Measurement of systolic pressure in both arm recorded simultaneously by mercury sphygmomanometer. Available data analyze and expressed in percentage, mean with SD and chi square test to see the significance of association. Results: According to anthropometric results of subjects 77.14 prcent subjects were having generalised obesity and 82.04 percent of subjects having abdominal obesity. 34.29 percent of subjects showed abnormally high (?10 mmHg) inter-arm systolic blood pressure difference. Both type of obesity showed positive association with blood sugar level but no association with interarm pressure difference. Conclusion: Interarm blood pressure difference is greater in individual having obesity or prolong duration of service. Such subjects are more susceptible to develop coronary artery disease or peripheral arterial disease in future. Early screening can help to detect the vascular events likely to occur in the future Keywords: Body mass index, Waist circumference, Interarm pressure difference, Random blood sugar

Ratcheting assessment of corroded elbow pipes subjected to internal pressure and cyclic bending moment

2021 ◽  
pp. 030932472198989
Author(s):  
Ali Salehi ◽  
Armin Rahmatfam ◽  
Mohammad Zehsaz
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Internal Pressure ◽  
Bending Moment ◽  
Axial Direction ◽  
Hoop Strain ◽  
Cyclic Bending ◽  
High Fatigue ◽  
The Impact ◽  
Cyclic Bending Moment

The present study aimed to study ratcheting strains of corroded stainless steel 304LN elbow pipes subjected to internal pressure and cyclic bending moment. To this aim, spherical and cubical shapes corrosion are applied at two depths of 1 mm and 2 mm in the critical points of elbow pipe such as symmetry sites at intrados, extrados, and crown positions. Then, a Duplex 2205 stainless steel elbow pipe is considered as an alternative to studying the impact of the pipe materials, due to its high corrosion resistance and strength, toughness, and most importantly, the high fatigue strength and other mechanical properties than stainless steel 304LN. In order to perform numerical analyzes, the hardening coefficients of the materials were calculated. The results highlight a significant relationship between the destructive effects of corrosion and the depth and shape of corrosion, so that as corrosion increases, the resulting destructive effects increases as well, also, the ratcheting strains in cubic corrosions have a higher growth rate than spherical corrosions. In addition, the growth rate of the ratcheting strains in the hoop direction is much higher across the studied sample than the axial direction. The highest growth rate of hoop strain was observed at crown and the highest growth rate of axial strains occurred at intrados position. Altogether, Duplex 2205 material has a better performance than SS 304LN.

CAE Correlation of Sealing Pressure of a Press-in-Place Gasket

2021 ◽  
Keyword(s):  
Internal Pressure ◽  
Pressure Distribution ◽  
Load Condition ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Test Results ◽  
Local Pressure ◽  
Cross Sectional ◽  
Pad Test ◽  
Sealing Pressure

The Press-in-Place (PIP) gasket is a static face seal with self-retaining feature, which is used for the mating surfaces of engine components to maintain the reliability of the closed system under various operating conditions. Its design allows it to provide enough contact pressure to seal the internal fluid as well as prevent mechanical failures. Insufficient sealing pressure will lead to fluid leakage, consequently resulting in engine failures. A test fixture was designed to simulate the clamp load and internal pressure condition on a gasket bolted joint. A Sensor pad using TEKSCAN equipment was used to capture the overall and local pressure distribution of the PIP gasket under various engine loading conditions. Then, the Sensor pad test results were compared with simulated CAE results from computer models. Through the comparisons, it is found that the gasket sealing pressure of test data and CAE data show good correlation for bolt load condition 500N when compared to internal pressure side load condition of 0.138 MPa & 0.276 MPa. Moreover, the gasket cross-sectional pressure distribution obtained by experimental tests and CAE models correlated very well with R2 ranging from 90 to 99% for all load cases. Both CAE and Sensor pad test results shows increase in sealing pressure when internal side pressure is applied to the gasket seal.

Numerical Simulation of Tube-Bending Process with Internal Pressure for Titanium Alloy Tube

2005 ◽  
Vol 475-479 ◽  
pp. 3279-3282
Author(s):  
Xia Huang ◽  
Yuan Song Zeng ◽  
Zhi Qiang Li ◽  
Xin Hua Zhang
Keyword(s):  
Titanium Alloy ◽  
Internal Pressure ◽  
Forming Process ◽  
Cold Bending ◽  
Bending Process ◽  
Thickness Prediction ◽  
Bending Radius ◽  
Experimental Values ◽  
Titanium Alloy Tube ◽  
Good Agreement

In this paper, a new cold bending process is presented to form the titanium alloy tubular part with small relative bend radius, that is, its centerline bending radius is less than 2 times the outside diameter of the tube. FEM is applied to simulate the forming process, and at the same time the results, such as the distribution of the stress and the wall thickness, prediction of defects area, the effects of the internal pressure and friction condition on the tube deformation, are also analyzed. Finally, experimental research was preformed. It is found that the numerical results are in good agreement with the experimental values.

scholarly journals Analysis of the Influence of Blanking Clearance on the Wear of the Punch, the Change of the Burr Size and the Geometry of the Hook Blanked in the Hardened Steel Sheet

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1261 ◽  
Author(s):  
Jacek Mucha ◽  
Jacek Tutak
Keyword(s):  
Steel Sheet ◽  
Cold Work ◽  
Sheet Thickness ◽  
Tool Materials ◽  
Burr Size ◽  
Thin Steel ◽  
Bending Radius ◽  
Friction Path ◽  
Cold Work Tool Steel ◽  
Selection Of

In this thesis, the results of an experimental analysis of blanking angled hooks with a punch of a sloping face in a thin steel sheet with a hardness of 55 HRC are presented. The blanking punch was made of K340 cold-work tool steel. Tests were carried out for three values of clearance, 5%, 10%, and 15% of sheet thickness. The results of the analysis of the influence of the number of cuts made by the punch on the growth of the burr at the sheet edge were presented. Moreover, the influences of the clearance on the initial values of burr (bh), deflection (Hb), and the bending radius (Rb) of the hook have been shown. The influence of the friction path on the intensity of degradation of working surfaces and the blanking edges of the punch was also demonstrated. The obtained results allow the selection of the proper clearance and new tool materials for blanking blades working in particularly difficult tribological conditions.

Long-Term Stress Analysis of Plastic Pipe Reinforced by Cross-Winding Steel Wire

2008 ◽  
Author(s):  
Xiang Li ◽  
Jinyang Zheng ◽  
Yaxian Li ◽  
Ping Xu ◽  
Chunying Zheng ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Volume Fraction ◽  
Axial Strain ◽  
Steel Wire ◽  
Creep Behaviour ◽  
Viscoelastic Model ◽  
Time Dependent ◽  
Hoop Strain ◽  
Steel Wires ◽  
Plastic Pipe

Plastic pipe reinforced by cross helically wound steel wires (PSP) is a new type of metal-plastics composite pipe developed in China. Time-dependent properties of PSP are investigated theoretically and experimentally in this paper. Although the steel wire can carry most of the loading in a liner elastic way, the time dependent behavior shown in the PSP should be further analyzed and described. Based on the structural features of PSP and the viscoelastic behaviors of HDPE in matrix, a three layer viscoelastic model is proposed to calculate time-dependent elastic stresses and strains in the PSP subjected to internal pressure. The experimental results show that the hoop strain decreases slowly, while the axial strain increases by 0.16% in 14000 minutes at constant internal pressure. Good agreement between theoretical results and experimental data shows that the three layer viscoelastic model is able to predict the time-dependent relationship of stress and strain in PSP. The effects of volume fraction and winding angle of the steel wires on the creep behaviour of the PSP subjected to an internal pressure are discussed in the end.

Research of grain size homogeneity effect on sheet stamping ability characteristics of Al2Mg and Al6Mg alloys

2019 ◽  
pp. 47-54
Author(s):  
E. A. Nosova ◽  
A. A. Fadeeva ◽  
M. A. Starodubtseva
Keyword(s):  
Grain Size ◽  
Cold Work ◽  
Structural Features ◽  
Grain Structure ◽  
Recrystallization Annealing ◽  
Spring Back ◽  
Sheet Stamping ◽  
Bending Radius ◽  
Homogeneity Effect ◽  
Quality Of Products

The quality of products made of sheet aluminum alloys strongly depends on the technological features of the sheet stamping process, as well as on the structure of sheet semi-finished products. The grain size and grain structure uniformity are among the key structural features that influence stampability. A method is proposed and the homogeneity of the grain structure is evaluated. Stampability of Al2Mg and Al6Mg aluminium alloys was evaluated based on measurements of the spring back index, minimum bending radius, stamping ratio, and Martens strain index. Cold work (with a strain degree of 20 %) and subsequent recrystallization annealing at temperatures of 250, 350 and 450 °C for 1 h were used to obtain a grain structure of (26,8 Ѓ} 7,4)÷(126 Ѓ} 43) μm (Al6Mg alloy) and (120 Ѓ} 11)÷(264 Ѓ} 130) μm (Al2Mg alloy) in size. As a result of processing, the effect of the initial grain size was revealed: the coarser structure of the Al2Mg alloy led to a larger grain size after strain and annealing. It was found that an increase in the grain size in both alloys leads to an increase in the Martens index and a decrease in the stamping ratio, which indicates higher stampability of the alloys in the drawing operations of sheet stamping. In the Al2Mg alloy, an increase in the grain size leads to a decrease in the spring back index by 1,5–1,7 times, and an increase in the minimum bending radius. In the Al6Mg alloy, an increase in the grain size leads to an increase in the spring back index by 1,1–1,2 times, and a decrease in the minimum bending radius. The Al6Mg minimum bending radius remains higher compared to Al2Mg regardless of the grain size. Grain size inhomogeneity in the Al6Mg alloy causes an increase in the Martens index and minimum bending radius, and a decrease in the stamping ratio. In the Al2Mg alloy, grain size inhomogeneity causes an increase in the Martens index and minimum bending radius, and a decrease in the stamping ratio. For the spring back index, the increase in grain size inhomogeneity causes a high scatter of data. In the Al6Mg alloy, the low annealing temperature led to the preservation of the non-recrystallized structure, which influenced the decrease in stampability.

scholarly journals Impact of Viscosity Variation, and Flow Rate on Coefficient of Discharge in Venturimeter Utilizing Taguchi Methodology

2020 ◽  
Vol 9 (4) ◽  
pp. 1838-1840
Keyword(s):  
Pressure Difference ◽  
Flow Measurement ◽  
Head Loss ◽  
Measuring Apparatus ◽  
Cross Sectional ◽  
Measuring Devices ◽  
Specific Geometry ◽  
Viscosity Variation ◽  
Coefficient Of Discharge ◽  
The Impact

Most of the industries are concerned with flow measurement and accurate measurement of fluid is important to obtain specific proportion as per process requirement. Generally Venturimeter (VM) is utilized in enterprises due to notable highlights offered by it. VM works on the principle of pressure difference i.e. Bernoulli’s principle. By varying cross sectional area of flow, it creates pressure difference along its length which is used to calculate theoretical discharge. Head loss in VM is less as compared to other flow measuring apparatus. Because of its specific geometry eddies formation is avoided causing less head loss. The coefficient of discharge (Cd ) is an important parameter always referred in case of flow measuring devices. For VM it varies from 0.95 to 0.99. Tests have been performed in accordance to Taguchi L9 O-A on cast iron pipe to examine the impact of variations of viscosity, and rates of flow on the Cd .

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