12 March 2025

Mingchao Liu

Mechanical Engineering, University of Birmingham

Morphing and moving matter: mimicking nature

Nature's ingenuity serves as a profound source of inspiration for developing advanced materials and robotic systems. In this presentation, we explore how biological phenomena inform innovative engineering solutions, focusing on morphing structures and moving mechanisms, both grounded in our understanding of the underlaying mechanics principles. We highlight morphing structure designs inspired by the segmentation architectures found in biological organisms and the dehydration-induced corrugated folding observed in Rhapis excelsa leaves. These designs emphasize adaptability and efficient shape transformation, showcasing the potential for creating functional, morphable systems. Additionally, we examine moving mechanisms, featuring a snap-through enabled insect-scale jumping robot modeled after click beetles and a magnetic robot inspired by the coordinated movements of cilia. These systems prioritize effective modeling to achieve rapid, efficient motion and agile navigation in complex environments. By integrating principles from biology and mechanics, this presentation illustrates how natural strategies can lead to cutting-edge technological advancements, offering new perspectives on the design and modeling of intelligent systems.

26 February 2025

Sam Harris
UCL

Penguin huddling and related interface problems

Penguins huddling in a cold wind can be represented by a two-dimensional, continuum model. The huddle boundary evolves due to heat loss to the huddle exterior, and through the re-organisation of penguins within the huddle as they seek to regulate their heat production. These two heat transfer mechanisms, along with area (or penguin number) conservation, gives a free boundary problem whose dynamics depend on both the dynamics interior and exterior to the huddle. The interior temperature is governed by a Poisson equation and the exterior temperature by the steady advection-diffusion equation, where the exterior, advective wind velocity is the gradient of a harmonic, scalar field. The conformal invariance of the exterior governing equations motivates the use of a conformal mapping method to solve for the exterior temperature gradient. The interior Poisson equation is not conformally invariant, so the interior temperature gradient is found instead using a combined adaptive Antoulas Anderson (AAA) and least-squares (LS) algorithm. The results show that, irrespective of the starting shape, penguin huddles evolve into an egg-like steady shape. This shape is dependent on the wind strength, parameterised by the Péclet numberPe, and a parameterβwhich effectively measures the strength of the interior self-generation of heat by the penguins. The numerical methods used in the penguin huddle problem, specifically the conformal mapping and AAA-LS methods, can be applied to further interface and free boundary problems, including in wildfire spread, biological electrostatics and vortex dynamics.

Emma Bouckley
DAMTP, University of Cambridge

The interplay of flow-induced, gravitational and mechanical compaction in soft porous media

Industrial applications motivate the consideration of flow through porous media that naturally slump due to gravitational stresses, the significance of which is captured by a non-dimensional gravity term that quantifies the relative importance of gravitational and elastic stresses. The asymmetry between upwards and downwards flow in gravity-slumped media results in distinct behaviour, with upwards flow initially rearranging gravitational compaction and maintaining a fixed depth before eventually inducing bulk compaction, which does not occur in downwards flow. Further, if a medium is mechanically compressed between two plates, as is the case in various industrial processes, then it takes up an external load which must be relieved before any bulk flow-induced compaction can occur. In particular, in this ‘pre-strained’ state, the overall depth remains fixed which was only possible for upwards flow in the un-pre-strained regime. In this talk we explore how the interplay of flow-induced, gravitational and mechanical compaction affects soft porous media and particularly how the constitutive laws for effective pressure and permeability, which encode the rheology of the solid matrix, classify media into two ‘types’ based on the compaction behaviour in the limit of large applied fluid pressure drop.

Gareth Alexander
Physics, University of Warwick

Chiral active matter and odd mechanics

I will describe my recent and ongoing research in chiral active matter in informal style. This is joint work with SJ Kole, Ananyo Maitra, Sriram Ramaswamy, and, separately, Sami Al-Izzi.

Sam Turley
PhD student, MathSys, University of Warwick

Causal entropy, control and leadership dynamics

Michiko Shimokawa

Nara Women's University, Nara, Japan

Bifurcation of rotational motion of elliptical camphor coated disk

23 October 2024

Matthew Butler

Clifford Fellow, Maths, University College London

Modelling mechanics of material replacement in biological systems

09 October 2024

Nathan van der Riet

PhD student, MathSys, University of Warwick

Minimal modelling of vesiculation processes as drivers of topology change in cell membranes

Joe Webber

Research Fellow, Maths, University of Warwick

Tubular hydrogel pumps through a responsive LENS

Mark Lynch

PhD student, Physics, University of Warwick 

Enej Caf

PhD student, University of Ljubljana