1. GTCOMPROP (Georgia Tech COMposite Material Member PROPerties calculator) Structural Engineering Software for the Analysis of Space Frame Structure Composed of Fiber Reinforced Composite Materials
Presented by Gwang-seok Na
Advisors : Dr. Leroy Z. Emkin & Dr. Abdul Hamid Zureick
Civil & Environmental Engineering
Georgia Institute of Technology
June 23, 2006
Good afternoon everyone.
My name is Gwangseok Na.
I’m in a PhD program at Georgia-Tech and working as a RA.
Today I hope to present a new engineering software named GTCOMPROP.
This name represent “Georgia Tech Composite material member properties calculator”
This implemented software is a structural engineering software for analysis of space frame structure of fiber reinforced composite materials

2. Overview Introduction
Theories on Calculation of Anisotropic Space Frame Member Stiffness Matrix
Software Implementation
Analysis Example
At first, I start introduction including motivation, objectives,
and some basic knowledge on FRP composite member
And I’ll present the theories on calculations of Anisotropic space frame member stiffness matrix
I’ll show main features of the implemented software
And nest, I’ll show the sample analysis case using the developed software

3. Motivation
FRP composite materials have attractive characteristics for civil engineering applications.
High Strength to Weight Ratio
Corrosion Resistance
Various Section Profiles
( Courtesy of Creative Pultrusions Inc. )
Conventional structural analysis techniques possess limitations in their ability to accurately analyze space frame structure composed anisotropic members.
A new pioneering technology has been developed and used in aerospace industry, but not civil industry because of its complexity.
As you know well, Fiber reinforced materials have a lot of attractive characteristics for civil engineering application
Like high strength ratio, corrosion resistance ……
[BULLET] …
The reason is because that conventional analysis techniques calculate the stiffness characteristics of member based on the cross section geometry alone and assume the material is isotropic and in addition to homogeneous
However a new pioneering technology has been developed in aerospace engineering area in order to calculate member stiffness of highly anisotropic member
But this technique has not been used in civil engineering because of the variety of complexities in using this techniques.

4. Objective
Develop analysis methodology, which can be used for civil engineering frame structure, based on Variational Asymptotic Beam Sectional Analysis Method.
Implement user-friendly engineering software that can fully utilize the developed analysis methodology.
So the objectives of this research is :
Developing analysis methodology that can be proper a for civil engineering application
Implement user-friendly engineering software that can fully utilize the developed analysis methodology
Next, I’ll talk about what is FRP composite materials

5. FRP Composite Materials – An Analogy
Reinforced Concrete (RC) Materials
Fiber Reinforced Polymeric (FRP)
Composite materials
Then I’ll talk about what is composite materials here.
To help understanding the concept of FRP composite materials
I compared the FRP composite materials case with Reinforced Concrete (RC) Materials
RC is also a simple composite materials composed with concrete and reinforcing bars
If we see concrete in micro-scale level
Concrete is also thought as composite of cement and aggregiate
Just like this RC, composite materials is composed with several different materials having different materials properties.
FRP composite materials is compsoed of matrix and reinforcing fibers
Just like concrete, matrix is also composed with resin and filler
Unlike RC case, various reinforcing arrangement are possible
In both cases, complex mathmatical models are required to get the effective material properties of these composite
This is called composite layers
This will be stacked to form the required thickness of flange of web of the member cross cross section
Concrete
Reinforcing Bars
Matrix
Reinforcing Fibers
Cement
Aggregate, Sand
and Additives
Resin
Filler and Additives

6. FRP Composite Materials
Reinforcement Systems (Fibers) [ Analogous to Reinforcing Bars in RC]
Provide main strength and stiffness in a fiber direction
Materials : Glass / Carbon (graphite) / Aramid (Kevler®) / Boron
Several fiber arrangement configuration is possible
Matrix [Analogous to Concrete in RC]
Transfer stress, protect fiber
Composed of resins and fillers
Resin [Analogous to Cement in RC] : Polyester / Vinylester / Epoxy
Filler [Analogous to Aggregate in RC] : Calcium Carbonate, Kaolin clay
Additives : Colorant Etc.
Reinforcing systems provide main stregth and stiffness in fiber direction
Glass, Carboon, Aramid are categorized into this
Main role of matrix is transfering stress and protecting fiber
Polyester, Vinylester and epoxy are popular resin material

7. FRP Composite Materials
Roving-reinforced layers
1 directional oriented fibers
Micromechanics models :
Chamis model (1984)
Halpin-Tsai(1968)
Continuous Strand Mat (CSM) - reinforced layers
Randomly oriented fibers
Micromechanics model :
Tsai-Pagano model (1968)
Christensen model (1972)
( Courtesy of Owens Corning Inc. )
The composite layers that all fiber are arranged in uni-directionally is called “Roving reinforced Layer”
There are variety of micro mechanics mathematical formulations that has been developed to get the elastic engineering properties of this composite layer.
Among them, the Chamis & Halpin-Tsai models are chosed in this research
The composite layers that reinforcing fibers are arranged randomly manner is called “Continuous strand mat reinforced Layer”
( Courtesy of Owens Corning Inc. )

8. FRP Composite Materials
A components (e.g., web or flange) of cross-section can be made with multiple-layers
CSM
Roving
CSM
This is a example of Box-cross section where the components of cross section is consist of multiple layers that was shown in previous slides,
“Roving reinforced layer” and “CSM reinforced layer”
These composite layers can be used to form the thickness of web or flange of cross-sectioin
Other combination of layers can be used by engineer and manufacturer.
Roving
CSM
Roving
CSM

9. Overview Introduction
Theories on Calculation of Anisotropic Space Frame Member Stiffness Matrix
Software Implementation
Analysis Example

10. Effective Material properties – Composite Layers
Roving–reinforced layers
1 directional oriented fibers
Micromechanics model :
Chamis model (1984)
Halpin-Tsai(1968)
Continuous Strand Mat (CSM) –reinforced layers
Randomly oriented fibers
Tsai-Pagano model (1968)
Christensen model (1972)
This part is a quick review of mathmatical formulations for Roving layers and CSM layers

11. Effective Material properties - Composite Layers
Chamis model (1984) for Roving-reinforced layers
E11 : Effective longitudinal
Modulus
E22 , E33 : Effective Transverse Moduli in axes 2 , 3
G12 , G13 , G23 : Effective Shear Moduli in plane 1-2,1-3, 2-3
ν12, ν13, ν23 : Effective Poisson’s ratio in plane 1-2, 1-3, 2-3
vf : Volume fraction of Fiber
vm : Volume fraction of Matrix
I’m not now presenting how these equations are folmulated
This is a result of mathmatical formulations of Chamis model
The 9 effective elastic engineering properties, 3 modulus, 3 shear modulus, 3 poisson’s ratios, can be calculated based on
3 elastic engineering properties of both fiber and matrix
The material properties of Fiber and Matrix are well known 1 2 3
Em , Gm , νm: Elastic Properties of Matrix
Ef , Gf , νf: Elastic Properties of Fiber

12. Effective Material properties - Composite Layers
Roving–reinforced layers
1 directional oriented fibers
Micromechanics models :
Chamis model (1984)
Halpin-Tsai(1968)
Continuous Strand Mat (CSM) –reinforced layers
Randomly oriented fibers
Micromechanics model :
Tsai-Pagano model (1968)
Christensen model (1972)

13. Effective Material properties - Composite Layers
Tsai-Pagano model (1968) for CSM-reinforced layers , , , ,
E : Effective Young’s modulus
G : Effective Shear modulus
ν : Effective Poisson’s ratio
Em : Matrix modulus
Ef : Fiber modulus
The effective material properties of CSM layer can be calculated
by developing equivalent isotropic material properties
Because fiber are orient in randomly oriented and have no particular direction
These equivalent isotropic material properties are based on the some fictious material properties
E11* and E22* are fictious modulus based on chamis model and Halpin-Tsai model
E11* is same in both case
But E22* have two different version based on micro mechnics models, and these can be showed in previous slides
vf : Volume fraction of Fiber
vm : Volume fraction of Matrix
E *11 , E *22 : Fictitious Longitudinal modulus and Transverse modulus by
Chamis model or Halpin-Tsai model

14. The thickness of a flange or web
Effective Material properties – Components of Cross-Sections
Lamination Theory - Homogenization 3 1 2
Layers n s x xt
Previous slides presented how to calculate Roving layer properties and CSM layer properties.
The problem is that the components of cross-section is consist of multiple layers
And each layer can be either roving layer and continuous strand mat layer
The properties of each layer can be different
Now, the special technique called Lamination theory can be used to get effective material properties of components of cross-section web or flange
This is kind of homogenization technique to derive the equivalent material properties.
The thickness of a flange or web

15. Effective Material properties – Components of Cross-Sections
Sun & Li 3D Lamination Method (1988)
Effective Elastic Properties
There are several Laminations theories are available
These are final mathematical formulation of Sun’ Li’s model
As we can see 9 elastic engineering properties can be calculated for each component of cross-section
Through this mathematical procedure engineer can

16. Anisotropic Member Stiffness – Sectional Analysis
Variational Asymptotic Beam Sectional Analysis (VABS) Method
(Developed by Dr. Hodges of Aerospace Eng. at Georgia Tech., 1994 under Gov. Fund.)
2D SECTIONAL ANALYSIS
3D FINITE ELEMENTS MODEL X2 X3 X1
SECTIONAL STIFFNESS
Ok I’ll talk about the most important theories in this program from here.
The most exact way of modeling the anisotropic member is known as modeling member with 3D finite elements
But this method is extremely difficult to model and time consuming.
That not proper for civil engineering
However VABS method broke down original 3D problem into two parts
The first one is 2D problem that generate so called sectional stiffness
The effective material properties that was calculated though 3D Lamination theories now can be used for 3D element of cross section
The second part is calculating the stiffness 1Dimensional member stiffness from 2D sectional stiffness through some mathematical approach X2 X3 X1
Start-end
End-end
MEMBER STIFFNESS
1D SPACE FRAME STRUCTURAL MEMBER

17. Overview Introduction
Theories on Calculation of Anisotropic Space Frame Member Stiffness Matrix
Software Implementation
Analysis Example

18. Software Implementation – GTCOMPROP Main window
The every mathematical procedures so far was implemented and integrated into this software

19. Software Implementation – Fiber Material Properties Database
Then I’ll explain about some important dialog windows in this program first
This dialog window is used to use to define the material properties of Fiber from a manufacturer
FIBER
FIBER

20. Software Implementation – Matrix Material Properties Database
This dialog window is used to use to define the matrix properties of Fiber from a manufacturer
MATRIX
MATRIX

21. Software Implementation – Effective Engineering Properties of Single Layer Calculation
This dialog is used to create composite material properties of various composite layers based on the previously introduced several micromechnics models
Here we can decide materials for Fiber and Matrix
And We can decide some required parameters
And We can select micromechanics model
The generated result can be stored for future use

22. Software Implementation – Effective Engineering Properties Calculation of Multi-Layered Components of Cross-Section
This dialog window is used to calculate the effective elastic engineering properties of components of cross section that is consist of multiple layers
We can construct specific layer sequence with previously calculated composite layers result
This is based on the previously presented 3D Lamination theory
The generate result also can be store for future use.
LAYER #1 (CSM)
LAYER #2 (ROVING) :

23. Software Implementation – Section Shapes (1/2)
 Sections for Isotropic Materials
RECTANGLE
CIRCULAR
AASHTO BEAMS
 Sections for Anisotropic or Isotropic Materials (1/2)
I SHAPE
T SHAPE
CHANNEL
L SHAPE
DOUBLE ANGLE

24. Software Implementation – Section Shapes (2/2)
 Sections for Anisotropic or Isotropic Materials (2/2)
N-SIDES HOLLOW TUBE
DOUBLE WEB BOX
BOX TUBE
CIRCULAR TUBE
TRIANGULAR CELL BOX
RECTANGULAR CELL BOX
BRIDGE DECK

25. Software Implementation – Section Generation

26. Software Implementation – Member Stiffness Calculations – Anisotropic Materials

27. Software Implementation – Section Properties Calculations – Isotropic Materials
Centroidal Location
Principal Axis Orientation
Cross Sectional Area
Principal Axis Shear Areas
Principal Axis Moments of Inertia
Torsion Constant
Warping Constant
Shear Center Location
Member Natural Stiffness Matrix

28. Overview Introduction
Theories on Calculation of Anisotropic Space Frame Member Stiffness Matrix
Software Implementation
Analysis Example

29. Analysis Example – Geometry of Sample Structure
At first, I start introduction including motivation, objectives,
and some basic knowledge on pultruded FRP composite
And If time’s permit, I’ll show a program demonstration.

30. Analysis Example – Wind-Loadings on Sample Structure
At first, I start introduction including motivation, objectives,
and some basic knowledge on pultruded FRP composite
And If time’s permit, I’ll show a program demonstration.

31. Analysis Example – Anisotropic Material Member Section Profiles
COLUMN
B = 20”, D = 20”,
tw=tf=1.0”
At first, I start introduction including motivation, objectives,
and some basic knowledge on pultruded FRP composite
And If time’s permit, I’ll show a program demonstration.
GIRDER
B = 12”, D = 30”, tw=tf=1.0”
STRUCTUR-1

32. Analysis Example – Anisotropic Material Member Section Profiles
At first, I start introduction including motivation, objectives,
and some basic knowledge on pultruded FRP composite
And If time’s permit, I’ll show a program demonstration.
BRACINGS
B = 6”, D = 6”, tw=tf=1.0”
STRUCTUR-2

33. Analysis Example – Effective Engineering Material Properties
 Nominal Elastic Properties of Composite Constituents
E (ksi)
G (ksi) v
E-glass Fiber
10,500
4,375
0.2
Polyester Matrix
573
210
0.36
 Volume Fractions
vfiber = 35.3 %
vmatrix = 63.0 %
vvoid = 1.7 %
CSM ( 10 oz/yd2 )
Roving ( 37.2 oz/yd2 )
2-CSM (10 oz/yd2 )
Ex = 2,822 ksi
Es = 1,896 ksi
Gxs = 640 ksi
vxs =
Roving ( 37.2 oz/yd2 )
2-CSM ( 10oz/yd2 )
Roving ( 37.2 oz/yd2 )
CSM ( 10oz/yd2 )

34. Analysis Example – Effective Engineering Material Properties

35. Analysis Example – Effective Engineering Material Properties

36. Analysis Example – Section Generation

37. Analysis Example – Section Generation

38. Analysis Example – Section Generation

39. Analysis Example – Anisotropic Material Member Stiffness Results Input: $
$ Space frame member KBB 6x6 matrix
$ Shape: W-SECTION
$ Description : GIRDER D=30 B=12 TF=1.0 TW=1.0 LENGTH = 11 FT
$ Units: INCHES LBS RADIANS
$ Member length: in
UNIT INCHES LBS RADIANS
MEMBER PROPERTIES
STIFFNESS MATRIX COLUMN
ROW e e e e e e+003
ROW e e e e e e+006
ROW e e e e e e+000
ROW e e e e e e+002
ROW e e e e e e+002
ROW e e e e e e+008
At first, I start introduction including motivation, objectives,
and some basic knowledge on pultruded FRP composite
And If time’s permit, I’ll show a program demonstration.

40. Analysis Example – Analysis Results ( No–Bracings )
At first, I start introduction including motivation, objectives,
and some basic knowledge on pultruded FRP composite
And If time’s permit, I’ll show a program demonstration.

41. Analysis Example – Analysis Results ( Bracings )
At first, I start introduction including motivation, objectives,
and some basic knowledge on pultruded FRP composite
And If time’s permit, I’ll show a program demonstration.

42. Summary of Current State of Research
Completed the implementation of a highly rigorous procedure for the member stiffness matrix for Anisotropic composite structural members
Completed incorporation of advanced anisotropic member stiffness calculation features with GT- STRUDL.

43. Thank you Questions ?