Module 4: Active SHM using Magnetostrictive Material
  Lecture 34: Convergence analysis for stress and strain using present model
 

Case Studies

The smart composite laminate is subjected to a point load P at the centre which is gradually being increased. Since it is a constant load, it is not going to alter the magnetic flux density. Hence, voltage in this case may be written as

(34.11)

hm is the thickness of MS layer, n is the number of turns per unit length, l the total length and ar the area of the cross-section of the conductor. The numerical inputs used in the referred analysis are presented in Table 34.1

Table 34.1 Numerical data used in analysis

Composite

urethane-vinyl ester

Laminate stacking sequence (cross ply 14 layers)

[(0/90)3 /0] s

Laminate stacking sequence (cross ply 28 layers)

[(0/90) 7] s

Laminate stacking sequence (cross ply 56 layers)

[(0/90)14] s

Balanced orthotropic (7 layered)

---

Total thickness of composite lamina

6.5 mm

Elastic modulus of fiber

72.4 GPa

Elastic modulus of resin

3.25 GPa

Elastic modulus of Terfenol- D

30.0GPa

Volume fraction of fiber

0.16

 

 Volume fraction of Terfenol- D

0.0224

 

 Poisson's ratio of fiber

0.20

 

 Poisson's ratio of resin

0.30

 

 Poisson's ratio of Terfenol-D

0.25

 

 Number of turns in the coil per meter length

500

 

 Carrier frequency

1000 Hz

 

 Carrier current

0.4 A

 

 Piezomagnetic coefficient, d

1.5 e -8 m/A

 

 Permeability, µ

14.13e -7

 

 Coupling coefficient of Terfenol-D, k

0.75

 

 Tensile Strength of Terfenol-D

28 MPa

 

 Compressive strength of Terfenol-D

700 MPa

 

 Fracture toughness of MS layer,

30 MPa-m 1/2

 

 Size of crack at delamination, c

2 mm

 

 Length of beam, l

600 mm

 

 Width of beam, b

100 mm