Numerical study of the influence of discharge wells on the stress–strain evolution in coal seam

2019 ◽  
Author(s):  
E. Evtushenko ◽  
I. Smolin
Keyword(s):  
Coal Seam ◽  
Numerical Study ◽  
Stress Strain ◽  
Strain Evolution

Numerical study of the stress-strain state of filter dams weakened by low-strength inclusions

1987 ◽  
Vol 23 (8) ◽  
pp. 760-765
Author(s):  
V. V. Skopetskii ◽  
V. S. Deineka ◽  
S. I. Rybachishin
Keyword(s):  
Strain State ◽  
Numerical Study ◽  
Stress Strain ◽  
Stress Strain State ◽  
Low Strength

Numerical study of the stress-strain state of threaded pipe joints

1987 ◽  
Vol 19 (11) ◽  
pp. 1567-1570
Author(s):  
N. V. Kokhanenko ◽  
Yu. V. Kokhanenko ◽  
Z. P. Ordynskaya
Keyword(s):  
Strain State ◽  
Numerical Study ◽  
Stress Strain ◽  
Stress Strain State ◽  
Pipe Joints

Numerical Modeling and Analytical Investigation of Autofrettage Process on the Fluid End Module of Fracture Pumps

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Mahdi Kiani ◽  
Roger Walker ◽  
Saman Babaeidarabad
Keyword(s):  
Residual Stresses ◽  
Kinematic Hardening ◽  
Analytical Formula ◽  
Strain Analysis ◽  
Material Model ◽  
Analytical Investigation ◽  
Stress Strain ◽  
Element Analysis ◽  
Hardening Material ◽  
Strain Evolution

One of the most important components in the hydraulic fracturing is a type of positive-displacement-reciprocating-pumps known as a fracture pump. The fluid end module of the pump is prone to failure due to unconventional drilling impacts of the fracking. The basis of the fluid end module can be attributed to cross bores. Stress concentration locations appear at the bores intersections and as a result of cyclic pressures failures occur. Autofrettage is one of the common technologies to enhance the fatigue resistance of the fluid end module through imposing the compressive residual stresses. However, evaluating the stress–strain evolution during the autofrettage and approximating the residual stresses are vital factors. Fluid end module geometry is complex and there is no straightforward analytical solution for prediction of the residual stresses induced by autofrettage. Finite element analysis (FEA) can be applied to simulate the autofrettage and investigate the stress–strain evolution and residual stress fields. Therefore, a nonlinear kinematic hardening material model was developed and calibrated to simulate the autofrettage process on a typical commercial triplex fluid end module. Moreover, the results were compared to a linear kinematic hardening model and a 6–12% difference between two models was observed for compressive residual hoop stress at different cross bore corners. However, implementing nonlinear FEA for solving the complicated problems is computationally expensive and time-consuming. Thus, the comparison between nonlinear FEA and a proposed analytical formula based on the notch strain analysis for a cross bore was performed and the accuracy of the analytical model was evaluated.

scholarly journals Experimental and Numerical Study of Rock Stratum Movement Characteristics in Longwall Mining

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Wan-rong Liu
Keyword(s):  
Stress Concentration ◽  
Coal Seam ◽  
Longwall Mining ◽  
Roof Rock ◽  
Numerical Study ◽  
High Stress ◽  
Engineering Practice ◽  
Rock Stratum ◽  
Working Face ◽  
Coal Wall

The roof fracture is the main cause of coal mine roof accidents. To analyze the law of movement and caving of the roof rock stratum, the roof subsidence displacement, rock stratum stress, and the rock stratum movement law were analyzed by using the methods of the particle discrete element and similar material simulation test. The results show that (1) as the working face advances, regular movement and subsidence appears in the roof rock strata, and the roof subsidence curve forms a typical “U” shape. As the coal seam continues to advance, the maximum subsidence displacement remains basically constant, and the subsidence displacement curves present an asymmetric flat-bottomed distribution. (2) After the coal seam is mined, the overburden forms an arched shape force chain, and the arched strong chain is the path of the overburden transmission force. The farther away from the coal seam, the smaller the stress concentration coefficient is, but it is still in a high stress area, and the stress concentration position moves toward the middle area of the goaf. The stress concentration in front of the coal wall is the source of force that forms the abutment pressure. (3) Above the coal wall towards the goaf, a stepped fracture was formed in the roof rock stratum. The periodic fracture of the rock stratum is the main cause of the periodic weighting of the working face. Understanding the laws of rock movement and stress distribution is of great significance for guiding engineering practice and preventing the roof accidents.

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