Your SlideShare is downloading. ×
0
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS

94

Published on

Published in: Education
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
94
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
3
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. BENCH STRUCTURAL INTEGRITY FOR OPTIMUM PERFORMANCE OF CABLE SHOVELS Eric Gbadam, PhD Student, Department of Mining & Nuclear Engineering Missouri S&T, Rolla, MO Samuel Frimpong, PhD, PEng Prof. & Chair, Department of Mining & Nuclear Engineering Missouri S&T, Rolla, MO September, 12 2013
  • 2. PRESENTATION OUTLINE Introduction Objectives Methodology  Finite Element Model Results and Discussions Conclusions Source: P&H, 2010 Source: Jacque & Riesland, 2013
  • 3. INTRODCUTION  Primary choice of equipment for oil sands excavation  The loads are transferred to formation via the crawlers  This cyclic loading reduces the oil sand shear strength & causes instability (failure)  Bench failure leads to lost in production and increase in downtime Source: Frimpong, 2012
  • 4. INTRODCUTION Cont’d  Load bearing capacity oil sands is low due to bitumen (8% to 15%)  Temperature changes during summer and winter  Average stress due to machine weight on crawlers be smaller to prevent sinkage  Shovel sinkage leads: carbody and side frame cracks associated increased downtime Increased maintenance cost Subsequent reduced availability Source: Grondin, 2008
  • 5. OBJECTIVES  To develop 3D Finite Element (FE) model shovel crawler-oil sands interactions using ABAQUS  To examine the average stresses and deformations on the formation during excavation
  • 6. METHODOLOGY The FE model were developed based on the principle of soil mechanics by assuming that: the oil sand is homogeneous, isotropic undergoing elasticplastic deformation; the crawler tracks were treated as a rigid strip footing resting on the oil sand; and the pressure distribution underfoot the tracks were uniform. The oil sand formation was modeled as elastic-plastic material with strain-softening Mohr-Coulomb criterion.
  • 7. Shovel Crawler-Oil Sands Interactions Table 1 Physical Dimensions of 3-D cable shovel crawler-oil sand model L (m) B (m) H (m) S (m) W(m) b (m) h (m) 25 20 10 10.5 2.21 4.5 1  Dimensions (Table 1) chosen to minimize boundary effect on formation behavior  Half symmetry model (Fig. 1) is used in the simulation to reduce computational time  Crawler track is modeled as a rigid rectangular footing  Contact interaction is modeled using Coulomb friction criterion (eqn 1) Fig. 1 3D half model
  • 8. FE Model of Crawler-Oil Sands Interaction Elastoplastic model of the oil sand under strain softening Mohr-Coulomb’s failure (eqn. 2) Table 2 gives the parameters used for the oil sand model and simulation ρ1 E1 ET1 T1 c2 Ψ2 (kg/m3) (MPa) (MPa) (°C) (kN/m2) (°) 0.1 25 10 10 1600 0.1 10 0.3 Source: 1Li et al (2012) and 2Anochie-Boateng (2008) 30.67
  • 9. FE Model of Crawler-Oil Sands Interaction  Meshes under the tracks are finer (Fig.2) to account for high stress concentration zone  The elements selcted for both oil sand and tracks was C3D8R, 3D, 8-node linear brick  This elements uses reduced integration technique which greatly reduces computation time Fig. 2 FE mesh and boundary condition for 3D oil sand-crawler model
  • 10. FE Model of Crawler-Oil Sands Interaction  The base of the model is fixed in all directions  All vertical boundaries are fixed in the perpendicular direction but free in the vertical direction  All nodes along the plane of symmetry given ZSYMM condition Fig. 2 FE mesh and boundary condition for 3D oil sand-crawler model
  • 11. FE Model of Crawler-Oil Sands Interaction Terzaghi’s classical bearing capacity equation forms the foundation for this model Overburden pressure used to account for depth of influence
  • 12. FE Model of Crawler-Oil Sands Interaction The loads are applied very slowly to avoid exciting the model Gravity and surcharge loads are applied to initiate the induced stresses
  • 13. FE Model of Oil Sands Deformation (a) (b) (d) (c) Fig. 3 Deformation contour plot of oil sand-crawler interface, (a) 3-D isometric view showing maximum deformation (b) Deformation under the tracks (c) deformation along the symmetry plane in 2-D and (d) Top view of oil sand deformation
  • 14. FE Model of Oil Sands Deformation  Deformation of the oil sand occurs underfoot the tracks and spreads laterally to the surface of the oil sand (Fig 3a), the maximum deformation of 2.497 cm under the tracks.  The deformation increases nonlinearly from the top surface to the (a) bottom of the formation as shown in Fig. 3(c). (b)  The top view (Fig. 3(d)) presents deformation spreading concentric with maximum occurring at the edges of the track and beyond.  Vertical displacement of the oil sand below the track is shown plotted in Fig.4 at a time of 0.13 seconds. (c)
  • 15. FE Model of Oil Sands Deformation  This figure depicts nonlinearly behavior of the formation under static loads Fig. 4 Displacement-time graph of oil sand-track interface
  • 16. FE Model of Oil Sands Deformation (a) Fig. 4 Zones of elastic and plastic strain at failure for oil sand, (a) maximum principal elastic strain, (b) 2-D elastic strain and (c) plastic strain (b) (c)
  • 17. CONCLUSIONS The following conclusions are made based on the FE simulation results from ABAQUS:  FE analysis has been implemented successful to fully produce 3-D oil sand-track interaction that reasonably predicts formation response to a static load.  Three distinct oil sand regions were observed from the plastic strain failure pattern: the region below the tracks recording larger strain at failure, region adjacent the tracks and expanding dipper and wider in all directions.

×