Parametric modeling and seismic analysis of RC structure based on secondary development in ABAQUS

Transcription

1 Parametric modeling and seismic analysis of RC structure based on secondary development in ABAQUS Topic source: 1. National Natural Science Foundation ( ) 2. Science and Technology Projects in Shenyang (F ) Reporter: Qiang Wang Shenyang Jianzhu University, China December 9, 2016

2 Introduction Present situation u 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.

3 Introduction Topic ideas u In order to improve the ability of nonlinear analysis of ABAQUS, several uniaxial constitutive 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.

4 Main contents 1 Parametric modeling of RC structure 2 Development of material subroutine 3 Nonlinear analysis 4 Collapse process analysis

5 (1) Parametric modeling 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.

6 (1) Parametric modeling Main flow 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.

7 (1) Parametric modeling Transformation of structural layout information 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

8 Transformation of material (1) Parametric modeling Materials in PMSAP Materials in ABAQUS

9 (1) Parametric modeling Transformation of section and rebar u Equivalent section and rebar for RC beam Concrete Equivalent rebar u Equivalent section and reinforcement for RC column Concrete Equivalent rebar Section steel

10 (1) Parametric modeling u Horizontal rebars and vertical rebars of the shear walls are viewed as rebar layers Concrete vertical rebars layer horizontal rebars layer

11 (1) Parametric modeling Transformation of Boundary Conditions Boundary in PMSAP Boundary in ABAQUS

12 (1) Parametric modeling Transformation of loads and masses uload Equivalent to even distributed load Load types in PMSAP Load in ABAQUS u Dead loads and live loads are respectively converted to masses.

13 Transformation of rigid slabs 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 transferred to their circumjacent beams. u In-plane translational DOFs and around-normal rotational DOFs of their circumjacent beams are coupling constrained. (1) Parametric modeling

14 Construction simulation (1) Parametric modeling uaccording to the construction order information of PMSAP, the corresponding analysis steps are created in ABAQUS. uin each steps, birth and death of elements are used to simulate the state of the accomplished structure.

15 (1) Parametric modeling 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.

16 (1) Parametric modeling Comparison of different mesh sizes

17 Verification of transformation uexample 1: frame structure (1) Parametric modeling Comparison of the PMSAP and ABAQUS models

18 Results of modal analysis (1) Parametric modeling PMSAP ABAQUS PMSAP ABAQUS PMSAP ABAQUS 1st vibration mode 2nd vibration mode 3rd vibration mode

19 (1) Parametric modeling Comparison of masses and periods

20 (1) Parametric modeling uexample 2: frame-shear wall structure Comparison of the PMSAP and ABAQUS models

21 Result of modal analysis (1) Parametric modeling PMSAP ABAQUS PMSAP ABAQUS PMSAP ABAQUS 1st vibration mode 2nd vibration mode 3rd vibration mode

22 (1) Parametric modeling Comparison of masses and periods

23 (1) Parametric modeling Interface of the transforming program(pa-trans)

24 (1) Parametric modeling

25 (2)Development of material subroutines The built-in concrete and steel constitutive model of ABAQUS Concrete damage plastic model of ABAQUS(CDP) This model can not be used for beam elements in space. Kinematic hardening model of ABAQUS(SPR1) This model is insufficiently considered for Bauschinger effect

26 (2)Development of material subroutines Concrete uniaxial constitutive model adopted in the Secondary Development Concrete uniaxial constitutive model (UCR1)

27 (2)Development of material subroutines Steel uniaxial constitutive model adopted in the secondary development a. skeleton curve b. unloading and reloading rules Steel uniaxial constitutive model I (USR1) Steel uniaxial constitutive model II (USR2)

28 (2)Development of material subroutines u Based on ABAQUS UMAT/VUMAT interfaces and the material constitutive models, six user material 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.

29 Profiles of the specimens (2.1)Example verification Specimen number concrete strength MPa rebar elastic modulus MPa Stirrup strength MPa Longitudi nal rebar strength MPa TP * TP * The experiment was performed by Prof. Kazuhiko Kawashima.

30 (2.2)Hysteretic loading analysis of column members Uniaxial lateral loading specimen TP kn /طشة 0 荷载 /kn mm /ئز«خ 位移 /mm Testing hysteretic curve Calculated curve with UCR1 and SPR1

31 (2.2)Hysteretic loading analysis of column members 荷载 /kn 0 荷载 /kn 位移 /mm 位移 /mm Calculated curve with UCR1 and USR1 Calculated curve with UCR1 and USR2 Calculated results with USR1 and USR2 more agree with the testing result.

32 (2.2)Hysteretic loading analysis of column members Biaxial lateral loading specimen TP77 u X direction 荷载 /kn 0 荷载 /kn 位移 /mm 位移 /mm Testing hysteretic curve Calculated curve with UCR1 and SPR1

33 (2.2)Hysteretic loading analysis of column members 荷载 /kn 0 荷载 /kn 位移 /mm Calculated curve with UCR1 and USR 位移 /mm Calculated curve with UCR1 and USR2 Calculated result with USR1 and USR2 is also closer to the testing result.

34 (2.2)Hysteretic loading analysis of column members u Y direction 荷载 /kn 0 荷载 /kn 位移 /mm 位移 /mm Testing hysteretic curve Calculated curve with UCR1 and SPR1

35 (2.2)Hysteretic loading analysis of column members 荷载 /kn 0 荷载 /kn 位移 /mm Calculated curve with UCR1 and USR 位移 /mm Calculated curve with UCR1 and USR2 Calculated result with USR1 and USR2 is also closer to the testing result.

36 (3)Nonlinear seismic analysis of structures Dynamic nonlinear analysis of frame structure under earthquake PMSAP model Transformed Model in ABAQUS

37 (3)Nonlinear seismic analysis of structures u Earthquake wave Acceleration peak value of the wave is adjusted to 510gal, and inputted in X direction.

38 (3)Nonlinear seismic analysis of structures u Top displacement time history 位移 (m) 节点 5 位移时程地震波时程 加速度 (cm/s 2 ) 时间 (s)

39 (3)Nonlinear seismic analysis of structures u inter-story displacement angle 楼层 层间位移角 Inter-story displacement angle

40 (3)Nonlinear seismic analysis of structures u Plastic distribution Plastic hinges primarily occur at the end of the beam end and the bottom column.

41 (3)Nonlinear seismic analysis of structures Frame-Core Wall Structure under Earthquake PMSAP Model Transformed Model in ABAQUS

42 (3)Nonlinear seismic analysis of structures u Earthquake wave Acceleration peak value is 400gal, and inputted in X direction.

43 (3)Nonlinear seismic analysis of structures u Top displacement time history 位移 m Midas Abaqus 时间 s Top displacement time history comparison between ABAQUS and Midas

44 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 > ε cu. ε cu =0.05. (4)Collapse analysis Rebar is considered as fracture, if ε > ε su (tensile) or ε < - ε su (compresive). ε su =0.15.

45 (4)Collapse analysis Simulation of the failure process of RC column (TP74) Ex.1 monotonic axial loading Ex.2 axial loading and uniaxial lateral cyclic loading Specimen loading diagram

46 (4)Collapse analysis Example 1: specimen TP74 with monotonic axial displacement loading 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.

47 (4)Collapse analysis u Failure of material Stress-strain curve of rebar fibers Stress-Strain curve of concrete 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

48 (4)Collapse analysis u Rendering of failure process (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.

49 (4)Collapse analysis Examples 2: specimen TP74 with the constant axial load and the lateral low cyclic load Hysteresis curves of with/without the failure criterion When the loading amplitude i s l a r g e r t h a n 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.

50 (4)Collapse analysis urendering of failure process (a) Nonlinear stage (b)protective layer of concrete fall off (c)movement of residual component after fracture of the specimen

51 (4) Collapse analysis Collapse process of frame structure Collapse

52 (5) Conclusion The parametric modeling software(pa-trans) can efficiently transform the model of PMSAP into ABAQUS. The developed constitutive models of concrete and rebar can reasonably describe the nonlinear performance of RC columns. The limit strain failure criterion can describe the fracture of component, and satisfy with the needs of the collapse process of RC structure.

53 (5) Conclusion Thanks for your attention!