Identification of stiffness and damping properties of composites from full field measurements Theory and simulations

1
Identification of stiffness and damping
properties of composites from full field
measurementsTheory and simulations
CompTest
2003

• A. Giraudeau, F. Pierron
• L.M.P.F. (JE 2381)
• ENSAM Châlons en Champagne

2
Scheme
1. Introduction
2. Presentation of the method
3. Virtual Fields
4. Application
5. Simulation Validation
6. Conclusion
3
Introduction
Prediction of vibrating behaviour
- Damping
Identification Experimental Modal Analysis
Anisotropic materials
Isotropic material
Anisotropic material
4
Presentation of the method

• 3 Points

• Excitation set up

• Full field measurements

• Application of the Principle of Virtual Works

5
Excitation set up
6
Full field measurements
- fields of out of plane slopes
- no contact
Examples Speckle Interferometry measurements
7
Principle of Virtual Works
Virtual works
(Elastic) (Dissipative)
(Clamping)
(Acceleration)
8
Actual fields of displacements

• Harmonic driven movement

• Absolute response

9
F. E. Simulation
Isotropic and viscoelastic material
Model
2048 shell elements
10
Actual fields of displacements

• Harmonic driven movement

• Absolute response

• Absolute response in complex notation

11
Choice of the Virtuals Fields

• Kinematically admissible

Actual fields
Virtual fields
12
Virtual works of external forces (VWEF)
13
Virtual works of internal forces (VWIF)

• Thin plate Love Kirchoff theory

• Isotropic viscoelastic material

14
Virtual works of inertial forces (VWIF)
15
Summary
VWIF VWEF VWAC
Virtual Works Principle

• at any time

16
Identification

• Interest for 2 equations

17
Simulation
Isotropic material
Proportional damping b
2048 shell elements
18
Simulation Results (1)
Excitation at resonances
19
Simulation Results (2)
Excitation at resonances
20
Simulation Results (3)
21
Conclusion

• Simultaneous identification of stiffness and
  damping

• Material damping

• Plate of any shape

• Resonant or non resonant response

• Set of specimens

• Excitation on a range of frequencies