MechE Colloquium: When Materials Bend the Rules: Buckling Response of Slender Structures Born of Constitutive Nonlinearities
Event details
| Date | 14.04.2026 |
| Hour | 12:00 › 13:00 |
| Speaker | Prof. Draga Pihler-Puzović, Department of Physics and Astronomy, University of Manchester |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
Abstract: Buckling of slender structures, such as perforated columns and cylindrical shells, underpins a wide range of systems and processes, from the structural failure of rocket fuselages and grain silos to engineered devices such as shock absorbers and crumple zones. Historically, research has primarily focused on predicting the onset of buckling—that is, the loss of the original configuration under excessive loading—rather than on understanding how structures evolve in the post-buckling regime. Recently, however, the study of buckling has experienced a renaissance, with post-buckling mechanical responses increasingly exploited to achieve new functionalities, for example enhancing fracture resistance in stretchable electronics and flexible displays.
While most existing studies consider elastically deforming systems whose behaviour arises primarily from geometric nonlinearities, this talk presents examples in which geometric effects are coupled with nonlinear constitutive responses, giving rise to new post-buckling mechanisms. First, we investigate the buckling of hard, perforated (“holey”) structures that exhibit auxetic behaviour but, unlike their purely elastic counterparts, undergo post-buckling softening. The resulting negative stiffness is captured using a pseudo-plastic constitutive model that describes nonlinearities emerging from the structural microarchitecture.
We then apply a similar framework to examine the buckling of beverage cans largely filled with liquid under axial compression. Whereas empty cylindrical shells typically develop periodic buckling patterns that break both axial and circumferential symmetry, liquid-filled cylinders buckle axisymmetrically. The resulting ring-shaped buckles are localized and emerge sequentially, progressively covering the can surface. We show that this behaviour arises from nonlinear, spatially anisotropic hoop stresses that soften and subsequently re-stiffen during compression.
Biography: Draga Pihler-Puzovic is a Reader in the Department of Physics and Astronomy at the University of Manchester and a core member of the Manchester Centre for Nonlinear Dynamics. Her research focuses on fluid–structure interactions, low-Reynolds-number flows, and the deformation of slender solid structures. She employs a combination of experimental, numerical, and analytical approaches to investigate fundamental problems in fluid and solid mechanics, and has made significant contributions to the understanding of instabilities arising in fluid–structure interactions, including viscous fingering beneath elastic sheets, sedimentation dynamics and deformation of mechanical metamaterials.
While most existing studies consider elastically deforming systems whose behaviour arises primarily from geometric nonlinearities, this talk presents examples in which geometric effects are coupled with nonlinear constitutive responses, giving rise to new post-buckling mechanisms. First, we investigate the buckling of hard, perforated (“holey”) structures that exhibit auxetic behaviour but, unlike their purely elastic counterparts, undergo post-buckling softening. The resulting negative stiffness is captured using a pseudo-plastic constitutive model that describes nonlinearities emerging from the structural microarchitecture.
We then apply a similar framework to examine the buckling of beverage cans largely filled with liquid under axial compression. Whereas empty cylindrical shells typically develop periodic buckling patterns that break both axial and circumferential symmetry, liquid-filled cylinders buckle axisymmetrically. The resulting ring-shaped buckles are localized and emerge sequentially, progressively covering the can surface. We show that this behaviour arises from nonlinear, spatially anisotropic hoop stresses that soften and subsequently re-stiffen during compression.
Biography: Draga Pihler-Puzovic is a Reader in the Department of Physics and Astronomy at the University of Manchester and a core member of the Manchester Centre for Nonlinear Dynamics. Her research focuses on fluid–structure interactions, low-Reynolds-number flows, and the deformation of slender solid structures. She employs a combination of experimental, numerical, and analytical approaches to investigate fundamental problems in fluid and solid mechanics, and has made significant contributions to the understanding of instabilities arising in fluid–structure interactions, including viscous fingering beneath elastic sheets, sedimentation dynamics and deformation of mechanical metamaterials.
Practical information
- General public
- Free