A Study of Multiple Laser Shock Micro-Adjustment Using Numerical Simulation

2014 ◽  
Vol 621 ◽  
pp. 25-31
Author(s):  
Di Zhang ◽  
Chun Xing Gu ◽  
Jun Wei Yuan ◽  
Zong Bao Shen ◽  
Hui Xia Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Shock Waves ◽  
Material Flow ◽  
Experimental Studies ◽  
Laser Shock ◽  
Flow Mechanism ◽  
Multiple Impacts ◽  
Fem Method ◽  
Shock Region ◽  
Adjustment Mechanisms

Laser shock micro-adjustment is a precise and noncontact adjustment technique using laser-shock-waves to adjust the curvature of micro-components. The experimental studies have indicated that: when laser shock region is located at the free end of cantilevers, multiple impacts are applied to achieve a large bending degree; meanwhile, different bending directions can be obtained with multiple impacts in the junction position. Efforts should been made to understand the mechanisms of multiple laser shock micro-adjustment. Two mechanisms have been proposed for describing the laser shock micro-adjustment in different laser shock regions, namely shock inertia mechanism and material flow mechanism. The proposed micro-adjustment mechanisms can predict bending angles and directions. To validate the proposed micro-adjustment mechanisms, numerical simulations were carried out based on the FEM method using the ANSYS/LS-DYNA software and the corresponding results demonstrate the proposed mechanisms.

scholarly journals An Approach to Determine Optimal Bow Configuration of Polar Ships under Combined Ice and Calm-Water Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 680
Author(s):  
Hui Li ◽  
Yan Feng ◽  
Muk Chen Ong ◽  
Xin Zhao ◽  
Li Zhou
Keyword(s):  
Numerical Simulation ◽  
Water Resistance ◽  
Numerical Technique ◽  
Experimental Studies ◽  
Resistance Index ◽  
Simulation Method ◽  
Present Approach ◽  
Calm Water ◽  
Level Ice ◽  
Ice Resistance

Selecting an optimal bow configuration is critical to the preliminary design of polar ships. This paper proposes an approach to determine the optimal bow of polar ships based on present numerical simulation and available published experimental studies. Unlike conventional methods, the present approach integrates both ice resistance and calm-water resistance with the navigating time. A numerical simulation method of an icebreaking vessel going straight ahead in level ice is developed using SPH (smoothed particle hydrodynamics) numerical technique of LS-DYNA. The present numerical results for the ice resistance in level ice are in satisfactory agreement with the available published experimental data. The bow configurations with superior icebreaking capability are obtained by analyzing the sensitivities due to the buttock angle γ, the frame angle β and the waterline angle α. The calm-water resistance is calculated using FVM (finite volume method). Finally, an overall resistance index devised from the ship resistance in ice/water weighted by their corresponding weighted navigation time is proposed. The present approach can be used for evaluating the integrated resistance performance of the polar ships operating in both a water route and ice route.

Laser shock micro-bulk forming: Numerical simulation and experimental research

2021 ◽  
Vol 64 ◽  
pp. 1273-1286
Author(s):  
Keyang Wang ◽  
Huixia Liu ◽  
Youjuan Ma ◽  
Jinzhong Lu ◽  
Xiao Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Experimental Research ◽  
Laser Shock ◽  
Bulk Forming

Shape Optimization and Strength Evaluation of Metal Welded Bellows Wave of Mechanical Seal

2008 ◽  
Vol 33-37 ◽  
pp. 1377-1382 ◽  
Author(s):  
Halida Musha ◽  
Mamtimin Gheni ◽  
Buhalqam
Keyword(s):  
Numerical Simulation ◽  
Bone Mass ◽  
Boundary Conditions ◽  
Shape Optimization ◽  
Reaction Diffusion ◽  
Mechanical Seal ◽  
Forming Process ◽  
Strength Evaluation ◽  
Fem Method ◽  
Initial Load

In this paper, the iBone (Imitation Bone) model which is coupled with Turing reaction-diffusion system and FEM, is used. The numerical simulation of bone forming process by considering the osteoclasts and osteoblasts process are conducted. The bone mass is increased with increase of the initial load value, then fibula and femur bones are obtained respectively by keeping the required bone forming value. The new S shape wave of metal welded bellow of mechanical seal are designed based on the the optimization results through this method. The S shape and V shape both were analyzed with FEM method. The same boundary conditions were given for two types of wave. The results are shown that the stresses mainly concentrated on the welded area. It is interesting that the value of the stresses of the two types of wave basically same. However, compressibility of the two types of wave is very different at the same computation stage. The compressibility of S shape wave was higher than V shape.

Research on Propagation Numerical Simulation of Blast Shock Waves in Subway Station

2013 ◽  
Vol 380-384 ◽  
pp. 1725-1728
Author(s):  
Yang Hu ◽  
Huai Yu Kang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Experimental Study ◽  
Shock Waves ◽  
Theoretical Basis ◽  
Damage Effect ◽  
Subway Station ◽  
Element Calculation ◽  
Dynamic Finite Element ◽  
Walking Pattern

In this paper, we Research on Propagation Numerical Simulation and damage effect of Blast Shock Waves in Subway Station by using LS-DYNA dynamic finite element calculation program , the results reproduce the formation process of the explosive flow field, and analysis the shock wave waveform, attenuation and walking pattern, provides the theoretical basis for further experimental study.

Dynamic Characterization of a Valveless Micropump Considering Entrapped Gas Bubbles

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Songjing Li ◽  
Jixiao Liu ◽  
Dan Jiang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Experimental Studies ◽  
Gas Bubbles ◽  
Chamber Pressure ◽  
Dynamic Characterization ◽  
Valveless Micropump ◽  
Performance Deterioration ◽  
Trapped Gas

Unexpected gas bubbles in microfluidic devices always bring the problems of clogging, performance deterioration, and even device functional failure. For this reason, the aim of this paper is to study the characterization variation of a valveless micropump under different existence conditions of gas bubbles based on a theoretical modeling, numerical simulation, and experiment. In the theoretical model, we couple the vibration of piezoelectric diaphragm, the pressure drop of the nozzle/diffuser and the compressibility of working liquid when gas bubbles are entrapped. To validate the theoretical model, numerical simulation and experimental studies are carried out to investigate the variation of the pump chamber pressure influenced by the gas bubbles. Based on the numerical simulation and the experimental data, the outlet flow rates of the micropump with different size of trapped gas bubbles are calculated and compared, which suggests the influence of the gas bubbles on the dynamic characterization of the valveless micropump.

scholarly journals Studies on laser-driven shocks using a Nd:glass laser

1997 ◽  
Vol 15 (2) ◽  
pp. 297-316 ◽  
Author(s):  
L.J. Dhareshwar ◽  
N. Gopi ◽  
C.G. Murali ◽  
B.S. Narayan ◽  
U.K. Chatterjee
Keyword(s):  
Experimental Studies ◽  
Research Centre ◽  
High Peak Power ◽  
Laser Shock ◽  
X Ray ◽  
Pressure Profiles ◽  
Ablation Pressure ◽  
Laser Velocity ◽  
Work Done ◽  
Nd:Glass Laser

A review of work done on laser generated shocks in solids using a high-peak-power Nd:glass laser in the Laser and Plasma Technology Division of the Bhabha Atomic Research Centre is presented in this paper. The 20-J/5-ns Nd:glass laser used in the experiments is able to produce focused laser intensities in the range of 5 × 1011-1013 W/cm2 and a shock pressure in the range of 0.1–5 Mbar. A l-J/100-ps Nd:glass laser is also being developed for laser shock studies, details of which are presented. Several diagnostics have been developed for laser shock studies of which the main diagnostics are optical shadowgraphy, optical interferometry, and laser velocity interferometry for particle velocity measurement. The measurement of ablation pressure in various types of targets, the scaling of ablation pressure with laser intensity, the effect of laser beam nonuniformity on shockfront or ablation pressure uniformity, the smoothing of shockfront and pressure profiles in high-Z coated and high-Z doped targets, and so on, are the various experimental studies conducted. We have tried to study X-ray driven ablation in aluminum and plastic targets using gold and copper as X-ray producing targets. Uniform pressure of about 0.1 Mbar has been generated over an area of 4 mm2

Effects of Gun Nozzle Geometry on High Velocity Oxygen-Fuel (HVOF) Thermal Spraying Process

1998 ◽  
Author(s):  
K. Sakaki ◽  
Y. Shimizu ◽  
Y. Gouda ◽  
A. Devasenapathi
Keyword(s):  
Numerical Simulation ◽  
Experimental Studies ◽  
Thermal Spraying ◽  
Deposition Efficiency ◽  
Divergence Angle ◽  
Nozzle Geometry ◽  
Oxide Content ◽  
Hvof Thermal Spraying ◽  
Throat Diameter ◽  
Spraying Process

Abstract Effect of nozzle geometry (such as throat diameter of a barrel nozzle, exit diameter and exit divergence angle of a divergent nozzle) on HVOF thermal spraying process (thermodynamical behavior of combustion gas and spray particles) was investigated by numerical simulation and experiments with Jet KoteTM II system. The process changes inside the nozzle as obtained by numerical simulation studies were related to the coating properties. A NiCrAIY alloy powder was used for the experimental studies. While the throat diameter of the barrel nozzle was found to have only a slight effect on the microstructure, hardness, oxygen content and deposition efficiency of the coatings, the change in divergent section length (rather than exit diameter and exit divergence angle) had a significant effect. With increase in divergent section length of the nozzle, the amount of oxide content of the NiCrAIY coatings decreased and the deposition efficiency increased significantly. Also, with increase in the exit diameter of the divergent nozzle, the gas temperature and the degree of melting of the particle decreased. On the other hand the calculated particle velocity showed a slight increase while the gas velocity increased significantly.

Effect of Laser Shock Peening on the Structure and Prosperity of K403 Alloy

2014 ◽  
Vol 670-671 ◽  
pp. 52-55
Author(s):  
Yan Chai ◽  
Wei Feng He ◽  
Guang Yu He ◽  
Yu Qin Li
Keyword(s):  
Surface Roughness ◽  
Grain Boundary ◽  
Compressive Stress ◽  
Residual Compressive Stress ◽  
Laser Shock Peening ◽  
Test Results ◽  
Laser Shock ◽  
Surface Microhardness ◽  
Shock Region ◽  
Shock Peening

To solve the crack and fracture problem in blade made of K403 alloy, the samples of K403 are laser shock processed and then the microstructure, microhardness, residual compressive stress and surface roughness of the samples are tested. The test results show that some grains are observed refined in the grain boundary of shock region, the microhardness improves in a depth of 0.8mm from the surface and the surface microhardness improves 16%, a residual compressive stress which is more than 450MPa is developed in a depth of 1mm from the surface, and obvious changes of the surface roughness are not tested.

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