PSI - Issue 44

ScienceDirect Structural Integrity Procedia 00 (2022) 000–000 Structural Integrity Procedia 00 (2022) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

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Procedia Structural Integrity 44 (2023) 2152–2157

XIX ANIDIS Conference, Seismic Engineering in Italy Sliding pendulum isolators without secretes Ivan Marenda a , Agostino Marioni a ,Marco Banfi b , Roberto Dalpedri b a Hirun International, Milano, Italy b Hirun International, Taichung, Taiwan XIX ANIDIS Conference, Seismic Engineering in Italy Sliding pendulum isolators without secretes Ivan Marenda a , Agostino Marioni a ,Marco Banfi b , Roberto Dalpedri b a Hirun International, Milano, Italy b Hirun I ternational, Taichu g, T iwan

© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy. Abstract Over the last decades, anti-seismic devices have gained increasing interest in the civil engineering field. The introduction of the base isolation system has led to a new concept in the construction panorama in terms of human life safety, a new way of thinking on new constructions, improvement and retrofitting on existent structures. Therefore, rubber and friction isolators have been deeply investigated to hence performances and predict dynamic behaviour during an earthquake. While the response of the former is characterised by the composition of the elastomeric compound, the latter features special materials able to dissipate energy by moving on smooth surfaces. This paper focuses on friction pendulum devices and addresses its attention on the behaviour of sliding materials. It is well-known that stick-slip phenomenon occurs when friction excitation is present and, in the anti-seismic field is important to reduce it and have a well-representative mathematical law able to describe it. Therefore, Hirun International after performing several treatments of the sliding materials has set up a special processing to guarantee a stable response of the HI-M material used on pendulum devices. The paper, after a brief presentation of the special sliding material, shows a comparison between the material with and without the treatment in terms of the force-displacement law. The paper also analyses in detail the cinematic behaviour of the sliding pendulum with one or two main sliding surfaces, with and without central articulation and determines the stress distribution in the sliding surfaces for the different cases. © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy Keywords: friction coefficient; pendulum device; contact; isolation system. 1. Introduction Over the last decades, the use of seismic isolation devices has become increasingly popular to improve the dynamic response of structures and avoid the loss of human life. In the world scenario there are different types of isolators that can be classified according to their physical and mechanical behaviour. The two most common isolators are the elastomeric and the friction pendulum devices. The rubber devices (HDRB, LDRB, LRB) are viscoelastic isolators made with high or low damping elastomers. The main standards limit the shear deformation ( D / T q ) of the elastomer to 2.5. As regarding damping, HDRBs can reach values of approximately 15% at shear deformation of 100% and decreases with increasing shear strain, while 2452-3216 © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the sci ntific committee of the XIX ANIDIS Conference, Seismic Engin ering in Italy Abstract Over the last decades, anti-seismic devices have gained increasing interest in the civil engineering field. The introduction of the bas isolation system h s led to a new concept in the constructio panorama in terms of human life safety, a new way f thinking on new constructions, improveme t and retrofitting on existent structures. Therefore, rubber d riction isolators h ve bee deeply inve iga ed to hence performances and predict dynamic behaviour during an earthqu ke. While the response of th former s charac rised by the composition of the las omeric compound, the latter features special materials able to dissipate energy by moving on smooth surface . This pap r focuses on friction pendulum devices and addresses its ttention on the behaviour of sl ding materials. It is well-known that stick-slip phen menon occurs wh n friction xcitation is present and, in the anti-seismic fiel is i po t nt to reduce it and have a well-re res tative mathematical law able to describe it. Th refore, Hirun I ernational after performi g sev ral treatments of the s iding materials has set up a special processing to guarant a stable response of the HI-M material used on pendulum devices. The pap , fter a brief pre entation f the special sliding ma erial, shows a c mparison betw en the material with an w thout t treatment in te ms of the force-displacement law. The paper also analy es in det l the cinematic beh viour of t e sliding pendulum with one or two main sliding urfaces, with and without central articulat on and d termines the stress distribution in the sliding surfaces for the differe t cases. © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review u der responsibility of h scientific committe of the XIX ANIDIS C nfere ce, Seismic Engineering in Italy Keywords: friction co fficient; pendulum devic ; conta t; isola ion system. 1. Introduction Over the last decades, the use of seismic isolation devices has become increasingly popular to improve the dynamic response of structures and avoid the lo s of human life. In the world scenario there are different types of isolators that can be classified according to their physical and m chanical behaviour. The two most common isolat rs a e the elastomeric and the friction pendulum dev es. The rubber evices (HDRB, LDRB, LRB) are viscoelastic isolators made with high or low damping elastomers. The main standards limit the shear deformation ( D / T q ) of he elast mer to 2.5. As regarding damping, HDRBs can reach values of approximat ly 15% at she r deformation of 100% and decreases with increasing shear strain, while 2452-3216 © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy. 10.1016/j.prostr.2023.01.275