Seminar & Colloquium
[세미나: 8월 23일(금), 오전 11시] Prof. Francesco Dal Corso, University of Trento
Title
Frictionless contact mechanics and configurational forces
Speaker
Prof. Francesco Dal Corso, Associate Professor, Department of Civil, Environmental and Mechanical Engineering, University of Trento
* Biography
After earning a PhD in Materials and Structural Engineering at the University of Trento, Italy, he had a postdoctoral fellowship at the Department of Applied Mathematics and Theoretical Physics, University of Cambridge, UK.
Francesco Dal Corso is currently an Associate Professor of Solid and Structural Mechanics at Department of Civil, Environmental and Mechanical Engineering of the University of Trento, Italy.
His research activity is devoted to the Mechanical behaviour of Solid and Structures. In particular, he dealt with problems related to the localization of deformation, plasticity, large deformations, homogenization, higher-order continua, stress concentrations and singularities, contact mechanics, configurational mechanics, and stability.
He has co-authored more than 50 journal papers. He has co-guest edited a Special Issue of the Journal of the Mechanics and Physics of Solids in 2020 and he is Associate Editor of Frontiers in Mechanical Engineering - Solid and Structural Mechanics section since 2021.
| Date | Friday, August 23rd , 2024
| Time | 11:00 ~
| Venue | 33동 125호(WCU 다목적실)
[Abstract]
Initiated by Eshelby [1], configurational mechanics provides a ground-breaking insight into problems where
a defect can change its position or increase in size and release energy, which is associated to a force, called
‘configurational’, acting on the defect and causing its movement.
Although configurational forces are historically assumed to be different in nature from Newtonian forces, we
show that the former can be interpreted as the latter for a special class of frictionless rigid constraint. More
specifically:
- The action of configurational forces on elastic structures is theoretically and experimentally proven
in the presence of a specific movable constraint: a frictionless, perfectly smooth and bilateral sliding
sleeve [2]. In particular, the presence of an outward configurational force at the exit of the sliding
sleeve is disclosed both via variational calculus and independently through an asymptotic approach;
- The stabilization of a rod against its fall in the presence of a gravitational field is shown to be
possible through a transverse oscillation of a sliding sleeve constraint. The motion results to be
periodic or quasi-periodic around a finite average value of the length of the bent rod [3].
- With a strong analogy to fracture mechanics, for a homogeneous elastic solid in frictionless contact
against a rigid and rectilinear constraint, ending with a rounded or sharp corner, it is shown that (i.)
a path-independent J-integral can be defined, (ii.) which is equal to the energy release rate G
associated with an infinitesimal growth in the size of the frictionless constraint, and thus gives the
value of the configurational force component along the sliding direction [4]. It is found that (iii.)
such a configurational sliding force is the Newtonian force component exerted by the elastic solid on
the constraint at the frictionless contact.
- Assuming the kinematics of an Euler-Bernoulli rod for an elastic body of rectangular shape, the
results (i.)-(iii.) lead to a new interpretation from a nonlinear solid mechanics perspective of the
configurational forces disclosed for one-dimensional structures of variable length.
- Approximate but closed-form solutions (validated with finite element simulations) are exploited to
provide further insight into the effect of configurational forces. In particular, two applications are
presented which show that a transverse compression can lead to Eulerian buckling or to longitudinal
dynamic motion, both realizing novel examples of soft actuation mechanisms.
The present results are relevant to the design of new soft actuation and energy harvesting mechanisms for
advanced technological applications involving extremely deformable structures and soft matter.
Acknowledgements
Financial support from the ERC advanced grant ERC-ADG-2021-101052956-BEYOND is gratefully acknowledged.
References
[1] Eshelby J.D. (1956) The continuum theory of lattice defects. Solid State Physics, 3, 79-144.
[2] Bigoni, D., Dal Corso, F., Bosi, F. and Misseroni, D. (2015). Eshelby-like forces acting on elastic structures: theoretical and experimental proof. Mechanics of Materials, 80, 368-374.
[3] Koutsogiannakis, P., Misseroni, D., Bigoni, D., Dal Corso, F. (2023). Stabilization of an elastic rod through an oscillating sliding sleeve. Journal of the Mechanics and Physics of Solids, 181: 105452.
[4] Dal Corso, F., Amato, M., Bigoni, D. (2024). Elastic solids under frictionless rigid contact and configurational force. Journal of the Mechanics and Physics of Solids, 188: 105673.
| Host | 최인석 교수(02-880-1712)