The novel approach proposed by the authors consists in directly measuring the forces transmitted between the two platforms through the damper, versus the relative motion of the platforms. In a previous paper we presented the design and calibration of a test rig where such measurements can be accomplished. In that paper some demonstration results were presented in order to show the capacity of the test rig. In this paper we add 1) a full reconstruction of translational and rotational damper motion, 2) comparisons with the results from a numerical model. The combination of the two allows to understand the contact conditions even in quite complex situations, and to explore the reasons for remarkable changes of the measured hysteresis cycles in operation. The damper used here is a „three point‟‟ damper. It has a statically determinate configuration, moreover its single line contact acts on the „fixed‟ platform, which is supported by the force sensors. This allows to fully determine forces, as the point of application in the force sensor plane is known. Experiments are performed under so called out-of-phase (OoP) and in-phase (IP) condition simulating two important motion types in the platform-damper mechanics. Experiments show that the friction coefficient can be very sensitive to the kinematics of the damper and can evolve in different ways in different tests under the same nominal outer parameters, especially for OoP condition. The combination of rolling and translation of the damper cause a complex influence on the friction coefficient at the three contact lines and vice versa; i.e., the damper kinematics and friction coefficient interact. For the long-run tests of this damper under OoP condition, there is a tendency of increasing the friction coefficient on both sides, which leads to micro-slip. The combination of rolling and translation of the damper contact is simulated by applying one macro-slip contact element at each contact point with normal and tangential stiffness through a numerical algorithm based on Newmark- beta method.

Investigation of under-platform damper kinematics and its interaction with contact parameters (nominal friction coefficient) / Gola, Muzio; Liu, Tong; BRAGA DOS SANTOS, Marcelo. - ELETTRONICO. - (2013). (Intervento presentato al convegno WTC 2013, 5th World Tribology Congress tenutosi a Torino nel September 8 – 13, 2013).

Investigation of under-platform damper kinematics and its interaction with contact parameters (nominal friction coefficient)

GOLA, Muzio;LIU, TONG;BRAGA DOS SANTOS, MARCELO
2013

Abstract

The novel approach proposed by the authors consists in directly measuring the forces transmitted between the two platforms through the damper, versus the relative motion of the platforms. In a previous paper we presented the design and calibration of a test rig where such measurements can be accomplished. In that paper some demonstration results were presented in order to show the capacity of the test rig. In this paper we add 1) a full reconstruction of translational and rotational damper motion, 2) comparisons with the results from a numerical model. The combination of the two allows to understand the contact conditions even in quite complex situations, and to explore the reasons for remarkable changes of the measured hysteresis cycles in operation. The damper used here is a „three point‟‟ damper. It has a statically determinate configuration, moreover its single line contact acts on the „fixed‟ platform, which is supported by the force sensors. This allows to fully determine forces, as the point of application in the force sensor plane is known. Experiments are performed under so called out-of-phase (OoP) and in-phase (IP) condition simulating two important motion types in the platform-damper mechanics. Experiments show that the friction coefficient can be very sensitive to the kinematics of the damper and can evolve in different ways in different tests under the same nominal outer parameters, especially for OoP condition. The combination of rolling and translation of the damper cause a complex influence on the friction coefficient at the three contact lines and vice versa; i.e., the damper kinematics and friction coefficient interact. For the long-run tests of this damper under OoP condition, there is a tendency of increasing the friction coefficient on both sides, which leads to micro-slip. The combination of rolling and translation of the damper contact is simulated by applying one macro-slip contact element at each contact point with normal and tangential stiffness through a numerical algorithm based on Newmark- beta method.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2527512
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