scholarly journals Study on the Dynamic Evolution of Through-Crack in the Double Hole of Elliptical Bipolar Linear-Shaped Charge Blasting

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Bo Wu ◽  
Shixiang Xu ◽  
Guowang Meng ◽  
Yaozhong Cui ◽  
Junhua Cai ◽  
...  
Keyword(s):  
Crack Growth ◽  
Growth Form ◽  
Simulation Analysis ◽  
Shaped Charge ◽  
Tensile Fracture ◽  
Mechanical Behaviors ◽  
Crack Penetration ◽  
Straight Line ◽  
Linear Shaped Charge ◽  
Continuous Crack

Seeking the law of through-crack in the double hole of shaped charge can help reveal the rock failure mechanism of directional controlled blasting. Using LS-DYNA numerical simulation analysis, the dynamic mechanical behaviors of double-hole crack development and double-hole crack penetration in elliptical bipolar linear-shaped charge blasting and ordinary blasting were compared and studied. The results showed that it was difficult to form a straight line through the double holes under ordinary blasting, while easy to cause over-under-excavation problems. The blasting of the elliptical bipolar linear-shaped charge had a significant effect on the formation of directional crack. The crack penetrated along the connecting center line of the two holes. The main crack growth form was tensile fracture mode, and the explosion gas was the important driving force for continuous crack growth. The elliptical bipolar linear-shaped charge blasting produced fewer cracks in the nonenergy-accumulating direction, which could effectively reduce the damage of the retained rock mass.

scholarly journals Study on Dynamic Evolution Law of Blasting Cracks in Elliptical Bipolar Linear Shaped Charge Blasting

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Bo Wu ◽  
Shixiang Xu ◽  
Guowang Meng ◽  
Junhua Cai ◽  
Han Wei ◽  
...  
Keyword(s):  
Main Crack ◽  
Laboratory Tests ◽  
Crack Formation ◽  
Simulation Analysis ◽  
Blast Hole ◽  
Shaped Charge ◽  
Dynamic Evolution ◽  
Remarkable Effect ◽  
Linear Shaped Charge ◽  
Decoupling Coefficient

Based on LS-DYNA numerical simulation analysis and comparison with laboratory tests, the blasting crack development dynamic evolution mechanism of elliptical bipolar linear shaped charge is analyzed. The development law of rock crack and optimal radial decoupling coefficient under different blast hole diameters were studied. The results revealed that the blasting with elliptical bipolar linear shaped charge had a remarkable effect on the directional crack formation, and the maximum effective stress of rock close to the position of shaped charge in the direction of concentrating energy is about 2.3 times of that in the direction of nonconcentrated energy. Moreover, the directional crack could be formed by blasting with elliptical bipolar linear shaped charge with different hole diameters, whilst the length of the main crack was related to the radial decoupling coefficient. Particularly, the main crack reached the longest when the radial decoupling coefficient was 3.36.

scholarly journals 3-D Numerical Study of Mechanical Behaviors of Pile-Anchor System

2014 ◽  
Vol 580-583 ◽  
pp. 238-242
Author(s):  
Ri Cheng Liu ◽  
Bang Shu Xu ◽  
Bo Li ◽  
Yu Jing Jiang
Keyword(s):  
Simulation Analysis ◽  
Numerical Study ◽  
Bending Moments ◽  
Mechanical Behaviors ◽  
Foundation Pit ◽  
Anchor System ◽  
Anchor Cable ◽  
Axial Forces ◽  
Toppling Failure ◽  
Potential Failure

Mechanical behaviors of pile-soil effect and anchor-soil effect are significantly important in supporting engineering activities of foundation pit. In this paper, finite difference method (FDM) was utilized to perform the numerical simulation of pile-anchor system, composed of supporting piles and pre-stressed anchor cables. Numerical simulations were on the basis of the foundation pit of Jinan’s West Railway Station, and 3D simulation analysis of foundation pit has been prepared during the whole processes of excavation, supporting and construction. The paper also analyzed the changes of bending moments of piles and axial forces of cables, and discussed mechanical behaviors of pile-anchor system, through comparisons with field monitoring. The results show that the parameters concluding vertical gridding’s number, cohesion of pile and soil, and pile stiffness have robust influences on supporting elements’ behaviors. Mechanical behaviors of supporting pile and axial forces of anchor cable changed dramatically, indicating that the potential failure form was converted from toppling failure to sliding failure.

Titan IVB Linear-Shaped Charge Assembly Explosive Train Transfer Reliability

AIAA Journal ◽  
2003 ◽  
Vol 41 (7) ◽  
pp. 1304-1313 ◽  
Author(s):  
Lien C. Yang ◽  
Ian P. H. Do
Keyword(s):  
Shaped Charge ◽  
Linear Shaped Charge

scholarly journals Analysis of the Crack Initiation and Growth in Crystalline Materials Using Discrete Dislocations and the Modified Kitagawa–Takahashi Diagram

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 358
Author(s):  
Kuntimaddi Sadananda ◽  
Ilaksh Adlakha ◽  
Kiran N. Solanki ◽  
A.K. Vasudevan
Keyword(s):  
Crack Initiation ◽  
Crack Growth ◽  
Growth Kinetics ◽  
Dislocation Dynamics ◽  
Internal Stresses ◽  
Stress Concentrations ◽  
Crystalline Materials ◽  
Discrete Dislocation ◽  
Continuous Crack ◽  
American Society

Crack growth kinetics in crystalline materials is examined both from the point of continuum mechanics and discrete dislocation dynamics. Kinetics ranging from the Griffith crack to continuous elastic-plastic cracks are analyzed. Initiation and propagation of incipient cracks require very high stresses and appropriate stress gradients. These can be obtained either by pre-existing notches, as is done in a typical American Society of Testing and Materials (ASTM) fatigue and fracture tests, or by in situ generated stress concentrations via dislocation pile-ups. Crack growth kinetics are also examined using the modified Kitagawa–Takahashi diagram to show the role of internal stresses and their gradients needed to sustain continuous crack growth. Incipient crack initiation and growth are also examined using discrete dislocation modeling. The analysis is supported by the experimental data available in the literature.

The Impact on the Pier of Shaped Charge Ice-Breaking and Numerical Simulation Analysis

2014 ◽  
Vol 501-504 ◽  
pp. 1883-1887
Author(s):  
Wen Yuan Meng ◽  
Jia Qing Li ◽  
Ying Kui Guo ◽  
Guan Chao Xu ◽  
Jun Wei Guo
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Maximum Stress ◽  
Simulation Analysis ◽  
Shaped Charge ◽  
Ice Water ◽  
The Impact

In the process of shaped charge ice-breaking , the response of piers is great under the impact of air, ice, water etc, and relates to integral security of the bridge. For the impact on the pier with burst points of the different distances is simulated by ANSYS / DYNA software, summarizes the impact on the pier of shaped charge ice-breaking, and obtains the maximum stress curves of the pier at different distances. Simultaneously, the paper analyses critical damaging- model of the C30 reinforced concrete piers in detail. The conclusion has a major role in guiding when shaped charge ice-breaking appears.

Constraint Effects on Ductile Crack Growth in SE(T) and SE(B) Specimens With Implications for Assessments of Tearing Resistance

2012 ◽  
Author(s):  
Claudio Ruggieri
Keyword(s):  
Crack Growth ◽  
Crack Tip ◽  
Stable Crack Growth ◽  
Primary Objective ◽  
Crack Growth Resistance ◽  
Tensile Fracture ◽  
Width Ratio ◽  
Cell Parameters ◽  
Crack Tip Constraint ◽  
Fracture Specimens

This work addresses a two-parameter description of crack-tip fields in bend and tensile fracture specimens incorporating the evolution of near-tip stresses following stable crack growth with increased values of the J-integral. The primary objective is to examine the potential coupled effects of geometry and ductile tearing on crack-tip constraint as characterized by the J-Q theory which enables more accurate correlations of crack growth resistance behavior in conventional fracture specimens. Plane-strain, finite element computations including stationary and growth analyses are described for SE(B) and clamped SE(T) specimens having different notch depth to specimen width ratio in the range 0.2 ≤ a/W≤0.5. A computational cell methodology to model Mode I crack extension in ductile materials is utilized to describe the evolution of J with Δa for the fracture specimens. Laboratory testing of an API 5L X70 steel using deeply cracked C(T) specimens is used to measure the crack growth resistance curve for the material and to calibrate the cell parameters. The present results provide additional understanding of the effects of constraint on crack growth which contributes to further evaluation of crack growth resistance properties of pipeline steels using SE (T) and SE(B) specimens.

Design and Simulation on the Rubber Conversion Track Wheel of the Loader

2012 ◽  
Vol 215-216 ◽  
pp. 1089-1092
Author(s):  
Zhen Ning Hu ◽  
Kai Yao ◽  
Xin Min Tian
Keyword(s):  
Work Ability ◽  
Simulation Analysis ◽  
Traction Force ◽  
Design Analysis ◽  
Road Surface ◽  
Concept Design ◽  
Obstacle Crossing ◽  
The Road ◽  
Wheeled Vehicle ◽  
Straight Line

The rubber conversion track wheel compare with the tyre has the adhesive performance well, the traction force big, well stability, compares with the steel caterpillar band chassis has the noise slightly, the quality light, the road surface non-damage merits.It can solve the wheeled vehicle the question which in the soft wet slippery location work ability drops. Based on the loader the rubber conversion track wheel design analysis results, has carried on the overall concept design to the loader track wheel.This plan uses the middle brace structure, the design absorption of shock stretching device, has solved the problem which track wheel bearing power small, the vibration and the caterpillar band tighten.Through to the loader track wheel straight line travel, climbing power, obstacle negotiation ability, changes ability the simulation analysis, has carried on the confirmation to the design proposal.The simulation result indicated that the loader track wheel road surface compatible, the climbing and obstacle crossing ability are good, change nimbly.

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