2008 International ANSYS Conference · 2008 International ANSYS Conference AUTODYN Simulation of...
Transcript of 2008 International ANSYS Conference · 2008 International ANSYS Conference AUTODYN Simulation of...
© 2008 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary
2008 International
ANSYS Conference
AUTODYN Simulation of Blasting at
Pointe du Bois Generating Station
Nick Rapolti
Engineering Analyst
SimuTech Group - Toronto
Shaun Beatty, P.Eng.
Senior Structural Engineer
KGS Acres
Ryan Penner, P.Eng.
Project Engineer
Manitoba Hydro
© 2008 ANSYS, Inc. All rights reserved. 2 ANSYS, Inc. Proprietary
Introduction
• The 97-year old Pointe du
Bois Generating Station is
located in Manitoba,
Canada
• The station is nearing end-
of-life and scheduled to be
replaced.
• Re-development options
include a new powerhouse
and spillway next to the
existing East Gravity Dam
© 2008 ANSYS, Inc. All rights reserved. 3 ANSYS, Inc. Proprietary
Background
• Re-development currently in the pre-design
phase.
• Construction would involve blasting of the bedrock
foundation near the existing East Gravity Dam.
Potential new
development
layoutExisting
powerhouse
East Gravity
Dam
© 2008 ANSYS, Inc. All rights reserved. 4 ANSYS, Inc. Proprietary
Objectives
• A test blast program in March 2008 in the
proposed construction area monitored the effects
on the bedrock and existing structures
• The finite element model of the East Gravity Wall
is calibrated from the results of test blasts
conducted on site
• Computer simulations will be employed to better
understand the potential effects of future
construction blasting for bedrock demolition
© 2008 ANSYS, Inc. All rights reserved. 5 ANSYS, Inc. Proprietary
Model Description
• Dam modeled from
construction drawings
• Ground surface
modeled from
bathymetry and survey
data
• Meshed using
GAMBIT
© 2008 ANSYS, Inc. All rights reserved. 6 ANSYS, Inc. Proprietary
ANSYS Structural Characterization
• Modal Analyses and Transient Analyses with
forced vibration of base (using ANSYS WB)
• 3D Model shows locations of highest velocity,
helps define locations of sensors in testing
• 2D sensitivity studies of:
– Mesh size
– Concrete properties
– Extent of water modeled
11th Mode (19.3 Hz)
© 2008 ANSYS, Inc. All rights reserved. 7 ANSYS, Inc. Proprietary
ANSYS Structural Characterization
• Sensitivity studies identified:
– Critical parameters affecting
structural response
– Effect of water behind dam
and amount of water needed
© 2008 ANSYS, Inc. All rights reserved. 8 ANSYS, Inc. Proprietary
AUTODYN Model
• The main challenge in these simulations is the
range of scales (Ø0.04m explosive, 400m dam)
• Remap process used to start with local fine
model, move to large coarse model
• Initial 2D axisymmetric model is 2x3.5m made
up of rock directly around explosive
• 3D models made large enough
to minimize effect of reflections
off boundaries
© 2008 ANSYS, Inc. All rights reserved. 9 ANSYS, Inc. Proprietary
AUTODYN Remap Process
• Small 2D axisymmetric model initiates blast
• Blast effects remapped onto larger 2D models
• Largest 2D model after remap is 36x36m
• Results remapped as initial state of 3D simulation
© 2008 ANSYS, Inc. All rights reserved. 10 ANSYS, Inc. Proprietary
Method of Correlation
• Model adjusted to match
results of test blast
program:
– Peak velocity predicted
by regression line
– Amplification between
base and top of dam
© 2008 ANSYS, Inc. All rights reserved. 11 ANSYS, Inc. Proprietary
Calibrated Simulation Results
• Preliminary simulation results correlate well with
regression line developed in testing
© 2008 ANSYS, Inc. All rights reserved. 12 ANSYS, Inc. Proprietary
Blast Propagation in Bedrock
• Pressure waves and velocity vectors vs time
© 2008 ANSYS, Inc. All rights reserved. 13 ANSYS, Inc. Proprietary
Motion of Structure
• Velocity vectors
over time
© 2008 ANSYS, Inc. All rights reserved. 14 ANSYS, Inc. Proprietary
Additional Correlations
• Time-History comparison at 85m from blast
• Testing
• Simulation
© 2008 ANSYS, Inc. All rights reserved. 15 ANSYS, Inc. Proprietary
Additional Correlations
• Frequency content comparison at 85m from blast
• Testing
• Simulation
© 2008 ANSYS, Inc. All rights reserved. 16 ANSYS, Inc. Proprietary
Additional Correlations
• Time-History comparison at top of dam
• Testing
• Simulation
© 2008 ANSYS, Inc. All rights reserved. 17 ANSYS, Inc. Proprietary
Additional Correlations
• Frequency content comparison at top of dam
• Testing
• Simulation
© 2008 ANSYS, Inc. All rights reserved. 18 ANSYS, Inc. Proprietary
Conclusions
• Highest velocity on dam occurs near blast
location although other regions displayed higher
structural amplification of vibrations
• Simulation correlates well with many aspects of
test results.
• The final model is ready for use in simulating new
blasting configurations to validate plans for
construction.