Research of Influence Factors of Initial Crack with Slotted Charge Blasting

2010 ◽  
Vol 143-144 ◽  
pp. 797-801
Author(s):  
Guo Liang Yang ◽  
Ren Shu Yang ◽  
Chuan Huo ◽  
C.C. Pan
Keyword(s):  
Peak Pressure ◽  
Influence Factors ◽  
Initial Crack ◽  
Energy Propagation ◽  
Damage Area ◽  
Initial Damage ◽  
Pressure Peak ◽  
Simulation Results ◽  
And Function ◽  
Function Time

By numerical simulation, the researches of effecting initial crack forming with slotted charge blasting are performed. The effecting factories conclude radial uncoupled parameter α and seam width W. Herein α adopts 1.43, 1.67 and 2, and 4, 6, 8 and 10 are adopted by W separately. The pressure peak is 15.5 GPa under α=1.67, and formed long cracks. With 6 and 8 mm seam widths, energy focus phenomenon is remarkable. The results show that initial damage of rock are decided by peak pressure of gas and function time. The seam width has significant effect to initial damage. With W adopting 6 and 8 mm, effective energy propagation is ensured and excessive damage area is avoided. The experiments validate the simulation results.

scholarly journals The Effect of Layer Variation Between Liner and Cement Mantle on Reducing Cracks of PMMA Material Hip Joints

2018 ◽  
Vol 73 ◽  
pp. 12013
Author(s):  
Eko Saputra ◽  
J Jamari ◽  
Han Ay Lie ◽  
Iwan Budiwan Anwar ◽  
Rifky Ismail ◽  
...  
Keyword(s):  
Finite Element ◽  
Hip Replacement ◽  
Cement Mantle ◽  
Initial Crack ◽  
Thickness Variation ◽  
Hip Joints ◽  
Element Simulation ◽  
Two Factors ◽  
Simulation Results ◽  
Reducing Stress

Failure of cement mantle of bond loosening between liner and cement mantle is an important issue in total hip replacement. Two factors that commonly cause cement mantle failure are initial crack and stress. A solution for reducing stress on the cement mantle has been proposed by adding insertion material between liner and cement mantle. Nevertheless, further study is needed to optimize the proposed solution. A possible option is to vary the thickness of the insertion material. If the thickness of the PMMA material is constant, then the variation of the insertion thickness will be followed by the variation of the thickness of the liner. Consequently, the stress value on the liner will follow the variation of liner thickness. The objective of this study is to examine the effect of the thickness variation of the insertion material to stress on cement mantle and liner using finite element simulation. Results revealed that the magnitude of stress and deflection decreased in the cement mantle and the liner along with the increasing thickness of the insertion material.

scholarly journals Discussion on the Theoretical Basis for Cross-Over Method Applied to Downhole Wave Velocity Test

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Qing Dong ◽  
Zheng-hua Zhou ◽  
Su Jie ◽  
Bing Hao ◽  
Yuan-dong Li
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Wave Velocity ◽  
Theoretical Basis ◽  
Influence Factors ◽  
P Wave ◽  
Engineering Practice ◽  
S Wave ◽  
Simulation Results ◽  
The Cross

At engineering practice, the theoretical basis for the cross-over method, used to obtain shear wave arrival time in the downhole method of the wave velocity test by surface forward and backward strike, is that the polarity of P-wave keeps the same, while the polarity of S-wave transforms when the direction of strike inverted. However, the characteristics of signals recorded in tests are often found to conflict with this theoretical basis for the cross-over method, namely, the polarity of the P-wave also transforms under the action of surface forward and backward strike. Therefore, 3D finite element numerical simulations were conducted to study the validity of the theoretical basis for the cross-over method. The results show that both shear and compression waves are observed to be in 180° phase difference between horizontal signal traces, consistent with the direction of excitation generated by reversed impulse. Furthermore, numerical simulation results prove to be reliable by the analytic solution; it shows that the theoretical basis for the cross-over method applied to the downhole wave velocity test is improper. In meanwhile, numerical simulations reveal the factors (inclining excitation, geophone deflection, inclination, and background noise) that may cause the polarity of the P-wave not to reverse under surface forward and backward strike. Then, as to reduce the influence factors, we propose a method for the downhole wave velocity test under surface strike, the time difference of arrival is based between source peak and response peak, and numerical simulation results show that the S-wave velocity by this method is close to the theoretical S-wave velocity of soil.

scholarly journals Plantar support adaptations in healthy subjects after eight weeks of barefoot running training

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8862
Author(s):  
Celso Sánchez-Ramírez ◽  
Luis M. Alegre
Keyword(s):  
Peak Pressure ◽  
Time Factor ◽  
Flat Foot ◽  
Barefoot Running ◽  
Running Training ◽  
Significant Difference ◽  
Increasing Trend ◽  
Pressure Peak ◽  
Reaction Forces ◽  
The Moment

Background Although the studies of barefoot running have intensified, it is still missing longitudinal work analyzing the effects of barefoot running on the phases of plantar support. The objective of this research was to analyze the modifications undergone by the Total Foot Contact (TFC) phase and its Flat Foot Phase (FFP) in subjects beginning the practice of barefoot running, in its acute and chronic effects. Methods A total of 28 subjects were divided into the Barefoot Group (BFGr) (n = 16) and the Shod Group (SHGr) (n = 12), evaluated before (Baseline) and after running for 20 min at 3.05 m·s−1 (Post 20 min Running), and at the end of a running training protocol with an 8-week long progressive volume (Post-8-week Training). The dynamic plantar support was measured with a baropodoscope. The duration of TFC (ms), the moment at which the FFP occurred, the maximum surface of TFC (MSTFC) (cm2), the FFP surface (SFFP) (cm2), the peak pressure of TFC (PP°TFC) (kg·cm−2), and the peak pressure of FFP (PP°FFP) (kg·cm−2) were recorded. The 3 × 2 ANOVA analysis was made to determine the effects and interactions that the condition produced (Shod/Barefoot), and the time factor (Baseline/Post 20 min Running/Post-8-week Training). Results The condition factor caused more significant effects than the time factor in all the variables. Duration of TFC in BFGr showed significant differences between the Baseline and Post-8-week Training (p = 0.000) and between Post-20-min Running and Post-8-week Training (p = 0.000), with an increasing trend. In the moment at which the FFP occurred a significant increase (p = 0.029) increase was found in Post-20 min Running (48.5%) compared to the Baseline (42.9%). In MSTFC, BFGr showed in Post-8-week Training values significantly higher than the Baseline (p = 0.000) and than Post-20-min Running (p = 0.000). SHGr presented a significant difference between the Baseline and Post-8-week Training (p = 0.040). SFFP in BFGr modified its values with an increasing trend (p = 0.000). PP°TFC in BFGr showed a significant decrease (p = 0.003) in Post-8-week Training (1.9 kg·cm−2) compared to the Baseline (2.4 kg·cm−2). In PP°FFP significant decreases were recorded in BFGr and between Post-8-week Training and Baseline (p = 0.000), and Post-8-week Training and Post 20 min Running (p = 0.035). Conclusions The adaptation took place after the 8-week training. The adaptations to running barefoot were characterized by causing an increase of the foot’s plantar support in TFC and in FFP, as well as a decrease of the plantar pressure peak in both phases. Also, there is an increased duration of the TFC and FFP, which may be related to an acquired strategy to attenuate the impacts of the ground’s reaction forces.

Design and Analysis of One Kind of Preliminary Storage Centrifugal Action Mechanism Applied to Submunition Fuze

2013 ◽  
Vol 718-720 ◽  
pp. 1624-1629
Author(s):  
Sheng Gang Xu ◽  
Yan Xuan Wu ◽  
Ning Jun Fan ◽  
Dong Qing Cheng ◽  
Dong Ze Qin
Keyword(s):  
Dynamic Simulation ◽  
Working Environment ◽  
Action Mechanism ◽  
Working Process ◽  
Development Status ◽  
Mechanical Structure ◽  
Simulation Results ◽  
And Function ◽  
Centrifugal Action

According to the requirement of the U.N. for the rate and function of dud, this paper proposes a project to improve mechanical structure of original submunition combing with the development status of submunition in China. With the characteristics of submunition fuzes structure and working environment, one kind of preliminary storage centrifugal action mechanism is designed in the paper. The principle and process of action are also elaborated. The paper makes calculation of reliability and does dynamic simulation by stages according to working process of submunition. Calculation and simulation results demonstrate that preliminary storage centrifugal action mechanism can be reliable and achieves the aim of design.

Short-Circuit Model and Simulation Characteristics of Synchronous Generators

2012 ◽  
Vol 241-244 ◽  
pp. 709-716
Author(s):  
Wan Qing Song ◽  
Qi Zhong Liu ◽  
Xu Dong Teng ◽  
Chao Gang Yu
Keyword(s):  
Theoretical Analysis ◽  
Simulation Model ◽  
Short Circuit ◽  
Influence Factors ◽  
Synchronous Generator ◽  
Synchronous Generators ◽  
Model And Simulation ◽  
Simulation Results ◽  
Physical Quantities ◽  
Tremendous Impact

In this paper, the electrical transient mode of synchronous generators is studied, four different simulation model of synchronous generator on sudden short circuit was built, various physical quantities were studied by simulation during the short circuit. By comparing theoretics with simulation, various physical quantities of synchronous generator produced tremendous impact and surge during the sudden circuit and they stabilized in the proceeding state of short circuit. Thoroughly simulation analyzed, the results of simulation are identical with theoretical analysis. The simulation results show that these influence factors should be considered when we design the relay protections.

Evaluation Study on the Network Impact Index of WeChat Based on Principal Component Analysis

2016 ◽  
Vol 13 (10) ◽  
pp. 7676-7679 ◽  
Author(s):  
Yi Liu
Keyword(s):  
Principal Component Analysis ◽  
Principal Components ◽  
Influence Factors ◽  
Principal Component ◽  
Modern Society ◽  
Component Analysis ◽  
Evaluation Study ◽  
Positive Energy ◽  
Impact Index ◽  
And Function

WeChat software is an important social tool in modern society. This paper discusses the network impact of WeChat from ten aspects including WeChat popularity, attention, video observability, network reputation, function usability, dissemination speed of information, transmission ratio of positive energy and impact of WeChat on network economy, politics and culture, and questionnaires on these ten influence factors are distributed to college students for investigation. Principal component analysis is used to deal with the survey results, the principal components of the ten factors are extracted, and the results show that WeChat popularity, attention, video observability, network reputation and function usability are the main components, in which WeChat popularity, attention and video observability are the factors having the greatest impact on the calculation. And this paper presents the function relationship between the main principal components of WeChat network impact index and these ten influence factors, to evaluate the network impact index of WeChat.

Finite Element Analysis of the Evolution of Damage during Equal Channel Angular Pressing of a Mg–3Al–1Zn Alloy

2012 ◽  
Vol 482-484 ◽  
pp. 2418-2423
Author(s):  
Feng Kang ◽  
Jing Tao Wang ◽  
Ping Cheng ◽  
Hai Ying Wu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Equal Channel Angular Pressing ◽  
Initial Crack ◽  
Flow Localization ◽  
Element Analysis ◽  
Fracture Characteristics ◽  
Angular Pressing ◽  
Tension And Compression ◽  
Simulation Results

Finite element analysis was used to simulate the evolution of damage in a Mg–3Al–1Zn alloy processed by equal channel angular pressing (ECAP). Oyane criterion for damage was selected to evaluate the fracture characteristics. Finite element modeling was used with experimental data obtained from tension and compression testing. The results show that initial crack may form in severe flow localization (i.e. in the inner corner) and these cracks may propagate, leading to billet segmentation. The flow grid in the simulation results is similar to that in the previous experimental results.

scholarly journals Long-term Coarsening and Function-time Evolution of an Initiator Powder

2017 ◽  
Vol 42 (12) ◽  
pp. 1352-1357 ◽  
Author(s):  
Amitesh Maiti ◽  
Tammy Y. Olson ◽  
T. Yong Han ◽  
Richard H. Gee
Keyword(s):  
Time Evolution ◽  
And Function ◽  
Function Time

scholarly journals Optimization of the Design of Pre-Signal System Using Improved Cellular Automaton

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yan Li ◽  
Ke Li ◽  
Siran Tao ◽  
Xia Wan ◽  
Kuanmin Chen
Keyword(s):  
Rational Design ◽  
Influence Factors ◽  
Design Parameters ◽  
Signal Timing ◽  
Signal System ◽  
Lane Changing ◽  
Traffic Demand ◽  
Driving Behaviors ◽  
Proposed Model ◽  
Simulation Results

The pre-signal system can improve the efficiency of intersection approach under rational design. One of the main obstacles in optimizing the design of pre-signal system is that driving behaviors in the sorting area cannot be well evaluated. The NaSch model was modified by considering slow probability, turning-deceleration rules, and lane changing rules. It was calibrated with field observed data to explore the interactions among design parameters. The simulation results of the proposed model indicate that the length of sorting area, traffic demand, signal timing, and lane allocation are the most important influence factors. The recommendations of these design parameters are demonstrated. The findings of this paper can be foundations for the design of pre-signal system and show promising improvement in traffic mobility.

scholarly journals The effect of LPG injector position on the SI engine operation

2007 ◽  
Vol 131 (4) ◽  
pp. 33-41
Author(s):  
Piotr JAKLIŃSKI ◽  
Łukasz GRABOWSKI ◽  
Mirosław WENDEKER ◽  
Jacek CZARNIGOWSKI ◽  
Piotr SZCZĘSNY ◽  
...  
Keyword(s):  
Peak Pressure ◽  
Injection System ◽  
Intake Manifold ◽  
Si Engine ◽  
Inlet Valve ◽  
Engine Operation ◽  
Toxic Emissions ◽  
Pressure Peak ◽  
Operation Parameters

The paper presents results of experiments on operation parameters of a 4-cylinder Holden 2.0 MPFI engine, supplied with LPG by means of sequential intake-manifold injection system, in the function of the distance between the injection ferrule and the cylinder’s inlet valve. Four positions of the injection ferrule along the manifold were tested, i.e. 115, 170, 230 and 310 mm from the valve. Indicated pressure, peak pressure and toxic emissions, in the function of injection start angle, were analyzed and compared for each position. The importance of the distance between injection ferrule and inlet valve was proved.

Sign in / Sign up

Export Citation Format

Share Document