PSI - Issue 44

A.Di Egidio et al. / Procedia Structural Integrity 44 (2023) 2136–2143

2141

6

A. Di Egidio, S. Pagliaro, A. Contento / Structural Integrity Procedia 00 (2022) 000–000 MPC 2 y =0 y =10 MPC 1 77.6 77.8 78 78.2 78.2 78.4 78.6 78.8 79 79.2 79.4 79.6 79.8 80.2 80.6 80.8 81 81.4 0.2 0.4 0.6 0.8 1.0 0.2 0.4 0.6 0.8 1.0 r e r c 11.1 12.6 13.5 14.7 15 15.9 16.2 16.5 17.1 17.7 17.7 18 18.6 18.6 18.9 18.9 19.2 19.2 19.5 19.8 19.8 20.1 20.1 20.4 20.4 20.7 21 21 21.3 21.3 21.6 0.2 0.4 0.6 0.8 1.0 r e r c Mode 1b Mode 2b 50 52 54 64 58 82 76 70 88 94 96 98 0.4 0.6 0.8 1.0 r c Mode 1a Mode 1b 2 4 8 12 16 20 28 36 40 46 0.4 0.6 0.8 1.0 r c Mode 2a Mode 2b

0.2 0.4 0.6 0.8 1.0

90 92

6

8 48 50 54 58 0.2 0.4 0.6 0.8 1.0 22 44

40 44 48

10

86 88

0.2

0.2

14

18

r e

r e

0.2 0.4 0.6 0.8 1.0

Fig. 3. Maps of the Modal Participating Coe ffi cients ( MPC ) of the structures coupled by the Kelvin-Voight device for di ff erent values of ψ ( c e = 0).

5. Seismic analysis

This section shows the e ff ectiveness of the coupling with an external structure in the case of seismic excitation. In this paper, two ground motion records are used as excitation. The records are selected accounting for the di ff er ences in their spectral characteristics. Fig. 4 shows the time-histories of the selected records that are

(a) Christchurch, REHS ground 2011 ChristChurch New Zeland; (b) Kobe, Takarazuka-000 station, ground motion recorded during the 1995 Japan earthquake;

a g

8.0

4.0

2 [ m/s ]

0.0

0.0

Christchurch

-4.0

Kobe

-6.0

0

10

20

30

40

0

5

10 (b)

15

20

(a)

Fig. 4. Time history of the earthquakes analysed: (a) Christchurch; (b) Kobe.

The results of the parametric analyses are arranged in maps that are contour plots of the performance indexes α 1 and α 2 in the ρ e − ρ c plane. Each map refers to a single seismic record and fixed ψ = 10 and c c /ω 1 ( m 1 + m 2 ) = 0 . 1, where ω 1 is the circular frequency of the first mode of the stand-alone frame structure. In the maps, the light grey colour is used for regions where the performance indexes are less than unity. In these regions, the coupling with the