PSI - Issue 64

Massimiliano Ferraioli et al. / Procedia Structural Integrity 64 (2024) 1025–1032 Ferraioli et al./ Structural Integrity Procedia 00 (2019) 000–000

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Table 2. Parameters of the bilinear equivalent SDOF system of the structure ( S ).

Direction m e *

d p

V p

V y

d y

K e

T e

r (S)

d p [mm]

 (S)

*

(S)

(S)

(S)

(S)

(S)

(S)

(S)



 h

 v

[kN ꞏ s 2 /mm]

[mm]

[kN]

[kN]

[mm]

[kN/mm]

[s]

[%]

[%]

X Y

1.1379 1.4758

1.417 50.00 35.29 2071 1462 8.70 96.08 1.183 73.85 62.43 1081 914 9.50 30.27

0.684 0.287 5.75 5.40 5.00 1.39 0.158 7.77 7.47 5.00

Table 3. Parameters of the bilinear equivalent SDOF system of the exoskeleton ( E ). Direction d p [mm] d p * [mm] V p (E) [kN] V y (E) [kN] d y (E) [mm] K e (E) [kN/mm] r (E)  (E)  h (E) [%] X 50.00 35.29 1610 1504 2.00 32.26 0.012 5.83 32.1 Y 73.85 62.43 1920 1799 2.85 26.30 0.012 5.61 31.9

Table 4. Design strength ( N D ) and stiffness ( K D ) of the SMADs, stiffness ( K B ), and type of the braces. X- Direction Y- Direction Floor N D [kN] K D [kN/mm] K B [kN/mm] Type N D [kN] K D [kN/mm] K B [kN/mm] Type 1 202.7 107 994  193.7/16 306.1 105 994  193.7/16 2 164.3 94 444  168.3/8 248.1 91 444  168.3/8 3 90.03 48 444  168.3/8 139.0 47 444  168.3/8

Table 5. Geometric and mechanical parameters of NiTi-based SMADs. (Wire diameter ( D ), Area ( A ), number ( n ), length ( L 0 ), yield displacement ( S y ) post-yield stiffness ratio (  ), ductility ratio(  )) X- Direction Y- Direction Floor D [mm] A [mm 2 ] n [-] L 0 [mm] S y [mm]  [%]  D [mm] A [mm 2 ] n [-] L 0 [mm] S y [mm]  [%]  1 12.40 120.68 4 144.4 1.90 1.22 6.88 15.24 182.22 4 222.1 2.92  1.22  6.88  2 11.16 97.81 4 133.2 1.75 1.22 6.88 13.72 147.69 4 207.7 2.73  1.22  6.88  3 8.35 54.78 4 146.1 1.92 1.22 6.88 10.27 82.72 4 225.3 2.96  1.22  6.88 

a)

b)

Fig. 6. Pushover curve and its bilinear idealization. a) X-direction; b) Y-direction.

a)

b)

Fig. 7. Bilinear idealization: a) Structure after retrofit step 1 ( S ); b) Exoskeleton (E).