Theoretical Analysis and Numerical Simulation on the Hydraulic Expansion of Double-Layered Tubes

2008 ◽  
Author(s):  
Fujun Liu ◽  
Jinyang Zheng ◽  
Shoubao Ding ◽  
Xiaolian Guo
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Theoretical Analysis ◽  
Suitable Condition ◽  
Stress And Strain ◽  
Maximum Relative Error ◽  
Hoop Strain ◽  
Whole Process ◽  
Good Agreement

The quality of hydro-expanded double-layered tubes depends on the hydro-expanding pressure. Therefore, it is very important to determine the range of the hydro-expanding pressure accurately during the fabrication of double-layer tubes. According to theories of elasticity and plasticity, the responses of double-layered tubes subjected to five kinds of cases were analyzed during the hydro-expanding process. And the stress and strain for inner and outer tubes of double-layered tubes were discussed. By using the relation of deformed compatibility of hoop strain, suitable condition of hydraulic expansion and variable range of hydro-expanding pressure were obtained, and the calculating formulas between the hydro-expanding pressure and residual contact pressure was derived. Use the non-linear FEA MSC.patran/marc code to simulate the deformation and stress distribution, the whole process of hydraulic expansion was numerically investigated, in which the nonlinearities of the material, geometry and contact were all taken into account. The results show that the range of the hydro-expanding pressure from the numerical simulation is in good agreement with those from theoretical calculation with a maximum relative error of 6.52%. The investigation on the hydraulic expansion of double-layered tubes may guide the engineering design and provide references for further research.

Simulation and Microstructure Predict during Hot Die-Forging of Cast Mg-7.0Al-0.2Zn Magnesium Alloy

2010 ◽  
Vol 152-153 ◽  
pp. 1293-1296
Author(s):  
Li Hong Wu
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Strain Distribution ◽  
Forging Process ◽  
Die Forging ◽  
Comparison Results ◽  
Hot Die Forging ◽  
Good Agreement

Employing the dies for aluminum alloy parts, the hot die-forging forming and numerical simulation of semi-continuous casting Mg-7.0Al-0.4Zn (AZ70) were carried out. It was indicated that AZ70 has a worse fluidity during forging and is consequently difficult to fill fully compared to aluminum alloys. The microstructure of the AZ70 forgings is in good agreement with the strain distribution generated by simulation, and strain distribution can predict the microstructure evolution. The comparison results can give a guideline on developing forging process and controlling forgings quality of the AZ70 alloy.

scholarly journals Numerical Simulation on Mechanical Strength of a Wooden Golf Stick

2018 ◽  
Vol 2 (1) ◽  
pp. 13
Author(s):  
Darianto Darianto ◽  
Bobby Umroh ◽  
Amrinsyah Amrinsyah ◽  
Zulfikar Zulfikar
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Maximum Stress ◽  
Impact Load ◽  
Golf Club ◽  
Stress And Strain ◽  
Sectional Area ◽  
Cross Sectional ◽  
Swing Speed ◽  
The Impact

In general, golf players only know the techniques used in Golf games, but do not know the golf sticks response that occurs when the ball is hit. Referred to as response is the stress and strain that arises from the impact load that occurs when the hitting member touches the ball. The objectives of this research are: (a) to analyze golf sticks response when impact occurs, and (2) to know the stress distribution that occurs in golf sticks. The golf stick design in this study uses the autodesk inventor software. The material used is Titanium for head stick and Graphite for stick rod. The basic principle of this study is based on simple swing pendulum method. The variables that will be used for simulation are: swing speed, that is difference between start and end speed, that is Δv = 272,2 m / s, impact time, which is the time when the ball touches the batter Δt = 0.0005 seconds, the volume of the head of the stick Vo = 96,727 mm<sup>3</sup>, the cross-sectional area of the stick A = 63,504 mm<sup>2</sup>, the head mass of the sticks ρ = 4620 kg / m<sup>3</sup>, and the modulus of titanium elasticity 9.6 e +10 Pa. From the simulation result on the surface of the golf club hitter is obtained as follows: σ<sub>max</sub> = 2.1231e +10 Pa at 1.231e-06 s, e<sub>max</sub> = 0.22115 m / m at 1.231e-06 s, and the maximum stress and strain is located in the area the connection between the stick and the head of the stick.

Numerical Simulation of Air-Deck Slotted Charge Blasting

2010 ◽  
Vol 143-144 ◽  
pp. 787-791 ◽  
Author(s):  
Guo Liang Yang ◽  
Ren Shu Yang ◽  
Chuan Huo ◽  
Y.L. Che
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Theoretical Analysis ◽  
Physical Process ◽  
Laboratory Tests ◽  
Decisive Role ◽  
Simulation Method ◽  
Numerical Simulation Method ◽  
Simulation Results ◽  
Air Deck

Air-deck ratio plays a decisive role in blasting engineering. Researchers have conducted extensive work to study the optimal air-deck ratio. But consensus has not been achieved. Especially slotted charge blasting, the study on it just starts. For its complicated physical process in blasting, it is difficult to perform theoretical analysis to obtain the law between blasting result and air-deck ratio. The numerical simulation method is adopted to study the effect of different air-deck ratio on stress distribution at first. And then laboratory tests are carried out to validate the simulation results. The conclusion may be drawn that good directional fracture could be obtained with air-deck ratio 33.3% ~ 50%. The achievement could provide reference for blasting engineering.

Flow over a containment dyke

1978 ◽  
Vol 87 (1) ◽  
pp. 179-192 ◽  
Author(s):  
H. P. Greenspan ◽  
R. E. Young
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Fluid Motion ◽  
Strong Shock ◽  
Safety Barrier ◽  
Large Tank ◽  
The Impact ◽  
Good Agreement

The wall of a large tank or reservoir breaks, sending fluid against a secondary containment dyke. The impact of the surging fluid against the safety barrier is studied. The results of theoretical analysis and numerical simulation (for vertical dykes) are in good agreement with experimental data concerning overflow and total spillage as well as the fluid motion after collision, including the development and formation of a strong shock. The dependence of spillage on the inclination of the dyke is also determined by experiment.

scholarly journals Estimation of the Dynamic Parameters of the Bearings in a Flexible Rotor System Utilizing Electromagnetic Excitation by a Built-In Motor

Actuators ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 1
Author(s):  
Yinsi Chen ◽  
Ren Yang ◽  
Naohiro Sugita ◽  
Jianpeng Zhong ◽  
Junhong Mao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rotor System ◽  
Radial Excitation ◽  
Maximum Relative Error ◽  
Fe Model ◽  
Dynamic Parameters ◽  
Flexible Rotor ◽  
Electromagnetic Excitation ◽  
Excitation Force ◽  
Good Agreement

Estimation of the dynamic parameters of bearings is essential in order to be able to interpret the performance of rotating machinery. In this paper, we propose a method to estimate the dynamic parameters of the bearings in a flexible rotor system. By utilizing the electromagnetic excitation generated by a built-in PM motor and finite element (FE) modeling of the rotor, safe, low-cost, and real-time monitoring of the bearing dynamics can be achieved. The radial excitation force is generated by injecting an alternating d-axis current into the motor windings. The FE model of the rotor and the measured frequency responses at the motor and bearing locations are used to estimate the dynamic parameters of the bearings. To evaluate the feasibility of the proposed method, numerical simulation and experiments were carried out on a flexible rotor system combined with a bearingless motor (BELM) having both motor windings and suspension windings. The numerical simulation results show that the proposed algorithm can accurately estimate the dynamic parameters of the bearings. In the experiment, the estimates made when utilizing the excitation force generated by the motor windings are compared with the estimates made when utilizing the excitation force generated by the suspension windings. The results show that most of the stiffness and damping coefficients for the two experiments are in good agreement, within a maximum error of 8.92%. The errors for some coefficients are large because the base values of these coefficients are small in our test rig, so these coefficients are sensitive to deviations. The natural frequencies calculated from the dynamic parameters estimated from the two experiments are also in good agreement, within a maximum relative error of 3.04%. The proposed method is effective and feasible for turbomachines directly connected to motors, which is highly significant for field tests.

Development and Application of Quality Control System for Highway Subgrade Construction

2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Tong Wang
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Detection Method ◽  
System Development ◽  
Effective Control ◽  
Construction Process ◽  
Development Mode ◽  
The Road ◽  
Whole Process

The compaction quality of the subgrade is directly related to the service life of the road. Effective control of the subgrade construction process is the key to ensuring the compaction quality of the subgrade. Therefore, real-time, comprehensive, rapid and accurate prediction of construction compaction quality through informatization detection method is an important guarantee for speeding up construction progress and ensuring subgrade compaction quality. Based on the function of the system, this paper puts forward the principle of system development and the development mode used in system development, and displays the development system in real-time to achieve the whole process control of subgrade construction quality.

Modeling of mass transfer in biofilms in oscillatory flow conditions using k-ɛ turbulence model

2003 ◽  
Vol 3 (1-2) ◽  
pp. 201-207
Author(s):  
H. Nagaoka ◽  
T. Nakano ◽  
D. Akimoto
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Turbulence Model ◽  
Uptake Rate ◽  
Oscillatory Flow ◽  
Substrate Uptake ◽  
Flow Conditions ◽  
Mass Transfer Mechanism ◽  
Substrate Uptake Rate ◽  
Good Agreement

The objective of this research is to investigate mass transfer mechanism in biofilms under oscillatory flow conditions. Numerical simulation of turbulence near a biofilm was conducted using the low Reynold’s number k-ɛ turbulence model. Substrate transfer in biofilms under oscillatory flow conditions was assumed to be carried out by turbulent diffusion caused by fluid movement and substrate concentration profile in biofilm was calculated. An experiment was carried out to measure velocity profile near a biofilm under oscillatory flow conditions and the influence of the turbulence on substrate uptake rate by the biofilm was also measured. Measured turbulence was in good agreement with the calculated one and the influence of the turbulence on the substrate uptake rate was well explained by the simulation.

Field Observation and Simulation of Sediment Resuspension in a Shallow Lake

1988 ◽  
Vol 20 (6-7) ◽  
pp. 263-270 ◽  
Author(s):  
K. Otsubo ◽  
K. Muraoka
Keyword(s):  
Numerical Simulation ◽  
Shallow Lake ◽  
Water Wave ◽  
Field Data ◽  
Sediment Resuspension ◽  
Field Research ◽  
Lake Kasumigaura ◽  
Bed Erosion ◽  
Current Water ◽  
Good Agreement

The dispersion and resuspension of sediments in Takahamairi Bay basin of Lake Kasumigaura were studied by means of field research and numerical simulation. The field data on wind direction and velocity, lake current, water wave, and turbidity were shown. Based on these results, we discuss how precipitated sediments were resuspended in this shallow lake. To predict the turbidity and the depth of bed erosion, a simulation model was established for this lake. The calculated turbidity showed good agreement with the field data. According to the simulated results, the turbidity reaches 200 ppm, and the bed is eroded several millimeters deep when the wind velocity exceeds 12 m/s in the lake.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

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