Authors:

EMBEDDED ELEMENT METHOD IN MESO-FINITE ELEMENT MODELING OF TEXTILE COMPOSITES

Authors: Seyyed Ahmad Tabatabaei , Prof. Stepan V. Lomov, Prof. Ignace Verpoest

Overview • Meso-FE modelling : importance, road maps(geometry , solid model and meshing procedure,..) • Meso-FE modelling (unit cell) modelling techniques • Evaluation of the embedded element method(EEM); 5-H Satin composite • Conclusion

2

Meso-FE Modeling of textile composites(1): Importance •The key step in multi-scale modeling of composites is meso-level. •Simplifications and less accurate models in analytical methods •Needs for accurate geometries •Development of Advance Numerical Codes: FEM ;Powerful Tool •Different FEM in textile composites:
“S” version (Fish), Zako et.al : M-cube method(Zako et. al) ; micro, meso, and macro (M- cubic), Domain superposition technique (DST)(Jiang).
Current paper: “Embedded element method” based on superposition technique

3

Meso-FE Modeling of textile composites(2): Road maps Road map for meso-FE; a:Linear , b:Non-linear

Road maps for meso-FE a:Linear b: Damage (Meso-FE modelling of textile composites: Road map, data flow and algorithms, Compos Sci Technol 2007; Lomov SV, Ivanov DS, Verpoest I, et al. 4

Meso-FE Modeling of textile composites(3): Geometry and solid modelling Geometry modelling

Meso-FEM of textile composites Damage modelling of the textile composites

WiseTex

WiseTex model is imported to Abqsus( Python script of D. Ivanov)

•Applying contact algorithm •Meshing the parts

Validation of the results

Virtual textile composites software WiseTex: Integration with micro-mechanical, permeability and structural analysis ;Ignaas Verpoest, Stepan V. Lomov( Composite science and technology(2005)) 5

Meso-FEM of textile composites(4): Meshing Geometry of the reinforcement(WiseTex)

Meshing(Mesh Tex)

Applying BC, Load, Displacement

Ansys Abaqus

Meshing the imported parts from WiseTex to Abaqus

6

Meso-FE (UC) modelling techniques(1)(Textile composites) Example: Unit cell of a woven composite Q: 1.Partitioning method?: Answer: NO;
Complex geometry

Matrix

Warp

Weft

2.Cut+ Merge(“full” method)?

YES!; But….

7

+

Meso-FE (UC)modelling techniques (2) Problems in the textile composites) Challenges: 1.Meshing of the matrix

+

Improper Surfaces

2.Missing the material orientation in full method

8

Meso-FE (UC) modelling techniques(3)(Problems in the textile composites) Challenges: 3.Interpenetration of reinforced parts

A rough solution for interpenetration problem: Cutting(removing) the penetrated regions

Weft Warp Penetration in Z direction nearly = 10 microns

Volume loss: 0.4% (mm^3) Problem: In damage analysis

Warp yarn-Front view 9

Warp yarn-Back view

Meso-FE(UC) modelling techniques (4) Is there another method for creating a proper unit Cell? 3: Embedded element method(EEM) Applicable : Any geometry, even 3D complex models Firstly used in Meso-FEM of composites using the Abaqus

10

Meso-FE(UC) modelling techniques (5): Embedded element method(EEM) exterior tolerance for embedded elements

Beam element

U(reinforcement part)=F(u(host part)) U:Translational degrees of freedom(DOF) Host part: Matrix

Matrix Yarn 11

Evaluation of the EEM (1): 5-H Satin composite (unit cell) WiseTex Model

Unit cell properties

12

Local strain in a 5-harness satin weave composite under static tension;Part2: Meso-FE analysis, Composite science and technology(2001): Dagummati et.al

Evaluation of the EEM (2): 5-H Satin composite( unit cells (full and EE methods)

Local strain in a 5-harness satin weave composite under static tension;Part2: Meso-FE analysis, Composite science and technology(2001) 13

Evaluation of the EEM (3): 5-H Satin composite(Homogenized properties: ”F” ,”EE”)

Local strain in a 5-harness satin weave composite under static tension;Part2: Meso-FE analysis, Composite science and technology(2001)

14

Evaluation of the EEM (4): 5-H Satin composite(stress fields)

DBC-Warp

DBC-Warp yarns(S22)

DBC-Warp yarns(S11) 15

Nodal-stress profile

Evaluation of the EEM (5): 5-H Satin composite(stress fields)

DBC-Weft yarns

DBC-Weft yarns(S11) 16

DBC-Weft yarns(S22)

Conclusion •EE can be used in meso-FEM of textile composites. •Reasonable results for homogenized properties from EEM. •Reasonable prediction of stress/strain filed (maximum and minimum stress regions in meso-FEM of textile composites). •Limitation for using in thermal-mechanical modelling; because of different applied constraints (elements); embedded element equation, temperature, and boundary conditions. •EEM should be assessed for damage analysis.

17

18

Thank you for your attention