parametric modeling and seismic analysis of rc...
TRANSCRIPT
Parametric modeling and seismic analysis of RC structure based on secondary
development in ABAQUS
Reporter: Qiang Wang Shenyang Jianzhu University, China
December 9, 2016
Topic source: 1. National Natural Science Foundation (51178279) 2. Science and Technology Projects in Shenyang (F16-175-9-00)
ØPresent situationu Research on nonlinear response and collapse damage of structures
under earthquake is an important subject in structural engineering.
u Seismic nonlinear and collapse analysis of RC structures can be
implemented by DEM or FEM.
u FEM is more widely used in numerical simulation.
u ABAQUS is a general FEM software, which is well known for its
ability of solving nonlinear problems.
u However, there exist many difficulties when nonlinear and collapse
analysis of RC structures is simulated based on ABAQUS.
Introduction
ØTopic ideasu In order to improve the ability of nonlinear analysis of ABAQUS,
several uniaxial const itut ive models for concrete and
reinforcement are developed through UMAT/VUMAT interfaces.
u Fracture criteria based on material strain are studied to realize
the fracture simulation of beam element.
u Parametric modeling in ABAQUS is studied for RC structures.
u The seismic response and collapse process of RC structures are
numerically simulated.
Introduction
Main contents
1 • Parametric modeling of RC structure
2 • Development of material subroutine
3• Nonlinear analysis
4 • Collapse process analysis
u It is very tedious and time-consuming to directly build the
model of RC structure in ABAQUS. It is worthy of transforming
the result of structural design into ABAQUS.
u Several transforming procedures have been developed from
SAP2000&MIDAS&YJK to ABAQUS. In these procedures,
structural models are converted to INP files in ABAQUS, so it
is difficult to modify or expand the structure model in
ABAQUS.
u PKPM is the main structural design software in China, but
absent of a direct transforming procedure to ABAQUS.
u Data loss easily occurs when a transformation from PKPM to
SAP2000/MIDAS, then to ABAQUS.
(1) Parametric modeling
(1) Parametric modeling
u Python is used as scripting language to manipulate ABAQUS kernel.
u Geometry layout information of nodes and components in
PKPM/PMSAP are extracted, described in IGES format and then
imported into ABAQUS.
u Other information of structure, such as material, section, rebar,
load and boundary conditions is automatically extracted from
PKPM/PMSAP, and then parametrically complemented in ABAQUS
/CAE.
u Meshing, checking, modifying, re-meshing and expanding the
structural model are carried out in ABAQUS / CAE.
ØMain flow
Ø Transformation of structural layout information
(1) Parametric modeling
Extracting the geometry information
of nodes and components from
PMSAP
Writing an IGES file and importing into
ABAQUS
Partitioning the shear walls and cutting hole in ABAQUS/CAE
Ø Transformation of material
(1) Parametric modeling
Materials in PMSAP Materials in ABAQUS
Ø Transformation of section and rebar
(1) Parametric modeling
u Equivalent section and reinforcement for RC column
Section steelEquivalent rebarConcrete
u Equivalent section and rebar for RC beam
Concrete Equivalent rebar
u Horizontal rebars and vertical rebars of the shear walls are
viewed as rebar layers
(1) Parametric modeling
Concrete vertical rebars layer horizontal rebars layer
Ø Transformation of Boundary Conditions
(1) Parametric modeling
Boundary in PMSAP Boundary in ABAQUS
Ø Transformation of loads and masses
(1) Parametric modeling
Load types in PMSAP Load in ABAQUS
Equivalent to even distributed load
uLoad
u Dead loads and live loads are respectively converted to masses.
u In order to reduce the calculation work, slabs in the rigid-slab region can be omitted in the structural model.
u Loads and masses of the omitted
s l a b s a re t r a n s f e r r e d t o t h e i r
circumjacent beams. u In-plane translational DOFs and
around-normal rotational DOFs of th e i r c i r c u m j a c e n t b e a m s a r e coupling constrained.
(1) Parametric modeling
ØTransformation of rigid slabs
ØConstruction simulation uAccording to the construction order information of PMSAP,
the corresponding analysis steps are created in ABAQUS.u In each steps, birth and death of elements are used to
simulate the state of the accomplished structure.
(1) Parametric modeling
Ø Mesh
uThe built-in mesh function of ABAQUS is used to mesh
the model.
uFor the more complex model, the local region of the
structural model can be manually re-meshed in
ABAQUS/CAE to ensure the mesh quality.
uThe CAE model can be exported to HyperMesh to gain
the expected mesh.
(1) Parametric modeling
(1) Parametric modeling
Comparison of different mesh sizes
ØVerification of transformationuExample 1: frame structure
(1) Parametric modeling
Comparison of the PMSAP and ABAQUS models
• Results of modal analysis
(1) Parametric modeling
PMSAP PMSAPPMSAPABAQUS ABAQUS ABAQUS
1st vibration mode 3rd vibration mode2nd vibration mode
• Comparison of masses and periods
(1) Parametric modeling
uExample 2: frame-shear wall structure
(1) Parametric modeling
Comparison of the PMSAP and ABAQUS models
• Result of modal analysis
(1) Parametric modeling
PMSAP PMSAPPMSAPABAQUS ABAQUS ABAQUS
1st vibration mode 2nd vibration mode 3rd vibration mode
• Comparison of masses and periods
(1) Parametric modeling
Ø Interface of the transforming program(PA-TRANS)
(1) Parametric modeling
(1) Parametric modeling
ØThe built-in concrete and steel constitutive model of ABAQUS
(2)Development of material subroutines
Concrete damage plastic model of ABAQUS(CDP)
Kinematic hardening model of ABAQUS(SPR1)
This model is insufficiently considered for Bauschinger effect
This model can not be used for beam elements in space.
ØConcrete uniaxial constitutive model adopted in the Secondary Development
(2)Development of material subroutines
Concrete uniaxial constitutive model (UCR1)
(2)Development of material subroutines
a. skeleton curve b. unloading and reloading rules
Steel uniaxial constitutive model II (USR2)
Steel uniaxial constitutive model I (USR1)
ØSteel uniaxial constitutive model adopted in the secondary development
uBased on ABAQUS UMAT/VUMAT interfaces and the mater ia l const i tut ive models , s ix user mater ia l subroutines are developed.u The subroutines in UMAT are used for ABAQUS/Standard
solver, and mainly for structural static analysis.
u The subroutines in VUMAT are used for ABAQUS/Explicit
solver, and mainly for structure dynamic analysis.
u IMPORT method is used to transmit the data between them.
(2)Development of material subroutines
ØProfiles of the specimens
(2.1)Example verification
The experiment was performed by Prof. Kazuhiko Kawashima.
Specimennumber
concrete strength
MPa
rebar elastic modulus MPa
Stirrup strength
MPa
Longitudinal rebar strength
MPa
TP74 29.66 2.1*105 321 357
TP77 31.31 2.1*105 321 357
ØUniaxial lateral loading specimen TP74
(2.2)Hysteretic loading analysis of column members
-60 -40 -20 0 20 40 60-150
-100
-50
0
50
100
150
شة؛/ط
kN
mm/ئز«خ
-60 -40 -20 0 20 40 60-150
-100
-50
0
50
100
150
荷载
/kN
位移/mm
Testing hysteretic curve Calculated curve with UCR1 and SPR1
(2.2)Hysteretic loading analysis of column members
Calculated curve with UCR1 and USR2
-60 -40 -20 0 20 40 60-150
-100
-50
0
50
100
150
荷载
/kN
位移/mm
-60 -40 -20 0 20 40 60-150
-100
-50
0
50
100
150
荷载/kN
位移/mm
Calculated curve with UCR1 and USR1
Calculated results with USR1 and USR2 more agree with the testing result.
ØBiaxial lateral loading specimen TP77
(2.2)Hysteretic loading analysis of column members
Testing hysteretic curve Calculated curve with UCR1 and SPR1
-60 -40 -20 0 20 40 60-150
-100
-50
0
50
100
150
荷载/k
N
位移/mm
-60 -40 -20 0 20 40 60-150
-100
-50
0
50
100
150
荷载
/kN
位移/mm
u X direction
(2.2)Hysteretic loading analysis of column members
-60 -40 -20 0 20 40 60
-100
-50
0
50
100
150
荷载
/kN
位移/mm
-60 -40 -20 0 20 40 60-150
-100
-50
0
50
100
150
荷载
/kN
位移/mm
Calculated curve with UCR1 and USR1 Calculated curve with UCR1 and USR2
Calculated result with USR1 and USR2 is also closer to the testing result .
(2.2)Hysteretic loading analysis of column members
-60 -40 -20 0 20 40 60
-100
-50
0
50
100
150
荷载/kN
位移/mm
-60 -40 -20 0 20 40 60-150
-100
-50
0
50
100
150
荷载/kN
位移/mm
u Y direction
Testing hysteretic curve Calculated curve with UCR1 and SPR1
(2.2)Hysteretic loading analysis of column members
-60 -40 -20 0 20 40 60
-100
-50
0
50
100
荷载/kN
位移/mm
-60 -40 -20 0 20 40 60
-100
-50
0
50
100
荷载
/kN
位移/mm
Calculated curve with UCR1 and USR1 Calculated curve with UCR1 and USR2
Calculated result with USR1 and USR2 is also closer to the testing result .
ØDynamic nonlinear analysis of frame structure under earthquake
(3)Nonlinear seismic analysis of structures
PMSAP model Transformed Model in ABAQUS
u Earthquake wave
(3)Nonlinear seismic analysis of structures
Acceleration peak value of the wave is adjusted to 510gal, and inputted in X direction.
u Top displacement time history
(3)Nonlinear seismic analysis of structures
0 2 4 6 8 10
-0.2
-0.1
0.0
0.1
0.2
位移(m)
时 间(s)
节点5位移时 程 地震波 时 程
加速度(
cm/s2 )
-400
-200
0
200
400
600
u inter-story displacement angle
(3)Nonlinear seismic analysis of structures
0.000 0.001 0.002 0.003 0.0040
2
4
6
8
10
12
楼层
层间位移角
Inter-story displacement angle
u Plastic distribution
(3)Nonlinear seismic analysis of structures
Plastic hinges primarily occur at the end of the beam end and the bottom column.
Ø Frame-Core Wall Structure under Earthquake
(3)Nonlinear seismic analysis of structures
PMSAP Model Transformed Model in ABAQUS
u Earthquake wave
(3)Nonlinear seismic analysis of structures
Acceleration peak value is 400gal, and inputted in X direction.
u Top displacement time history
(3)Nonlinear seismic analysis of structures
0 5 10 15 20-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
位移
m
时 间s
Midas Abaqus
Top displacement time history comparison between ABAQUS and Midas
Ø Failure criterion When the tensile(compressive ) strain of a fiber in the element section reaches its limit strain value, this fiber will be killed. it means that material in a certain range of element section is failure . When all fibers of the element are failure, the element will be killed, and it can not be recovered. Beam/column component is broken into segments.u Failure criterion of rebar
u Failure criterion of concrete Concrete is considered as fracture, if ε > εcu. εcu =0.05 .
(4)Collapse analysis
Rebar is considered as fracture, if ε > εsu (tensile) or ε < - εsu (compresive) . εsu =0.15 .
Ø Simulation of the failure process of RC column (TP74)
(4)Collapse analysis
Ex.1 monotonic axial loading Ex.2 axial loading and uniaxial lateral cyclic loading
Specimen loading diagram
Ø Example 1: specimen TP74 with monotonic axial displacement loading
(4)Collapse analysis
Curve of Vertical reaction force-displacement
OA segment, The concrete and the reinforced
common pressure rise stage, at the A point of
the concrete to achieve the peak compressive
strength.
AB segment, Concrete and reinforced common
pressure drop stage, at the B point of the
concrete was crushed.
BC segment, Reinforced by the elastic stage
alone, C point for the steel yield 。
BC segment, The steel bar alone yield pressure
stage, the final point of reinforcement at the D
was crushed, thus reinforced concrete column
members completely destroyed.
u Failure of material
(4)Collapse analysis
Stress-strain curve of rebar fibers
With the increase of displacement loaded on the column top, the compressive strain
of reinforced concrete and concrete are gradually increased, and the failure of the member
is occurred after reaching the respective limit of ultimate compression strain
Stress-Strain curve of concrete fibers
uRendering of failure process
(4)Collapse analysis
(a) initial Loading (b) concrete damage (c) Reinforcement damage(d)Movement of residual component after damage
The results are in accordance with the constitutive relations of reinforced concrete and concrete and the failure criterion.
Ø Examples 2: specimen TP74 with the constant axial load and the lateral low cyclic load
(4)Collapse analysis
Hysteresis curves of with/without the failure criterion
When the loading amplitude
i s l a r g e r t h a n 2 2 0 m m , t h e
hysteresis loops are completely
"lying down" and flattened, and
the energy dissipation capacity of
t h e c o m p o n e n t s h a s b e e n
reduced to a very low level due to
the failure of most of the fibers in
the calculation results considering
the failure criterion.
The hysteresis curve without
the failure criterion is still fat.
(4)Collapse analysis
(a) Nonlinear stage (b)Protective layer of concrete fall off (c)Movement of residual component after fracture of the specimen
uRendering of failure process
ØCollapse process of frame structure
(4) Collapse analysis
Collapse
Ø The parametric modeling software(PA-TRANS) can efficiently transform the model of PMSAP into ABAQUS.
Ø The developed constitutive models of concrete and rebar can reasonably describe the nonlinear performance of RC columns.
Ø The limit strain failure criterion can describe the fracture of component , and satisfy with the needs of the collapse process of RC structure .
(5) Conclusion
Thanks for your attention!
(5) Conclusion