Integrated Material-Modelling-Manufacturing paradigm for Mechanical Meta-regulators (I5M)

Mechanical metamaterials are materials that are specially designed to have unprecedented mechanical properties and multi-physics characteristics beyond those of classical natural materials. The properties of mechanical metamaterials are defined by their topology and geometrical architecture, and the characteristics of the materials which they are made from. Changing any of these directly affects the structural response and allows us to explore new areas in the material property space. Interesting properties that metamaterials exhibit include zero and negative Poisson's ratio leading to unexpected behaviour when subjected to mechanical stresses and strains, zero and negative stiffness, ability to absorb/dissipate energy and ability to isolate vibration. These properties give metamaterials high industrial value as illustrated by the global metamaterials market, valued at $1.5 billion in 2022 and forecast to grow to $22.9 billion by 2028.

The focus of I5M is Mechanical Constant-Force MetaMaterials (CFMMs). These can deliver a quasi-constant output force over a range of input displacements (i.e., they can apply a constant pressure on a surface or object). This means they can act as passive force regulation and vibration isolation devices without any need for sensors and complex electromechanical control systems and have potential to be used in many applications such as robotic automation, overload protection, and precision manipulation. Despite recent advances in materials and manufacturing, CFMM development suffers drawbacks such as limited material selection and working range, unrealistic theoretical assumptions, high computational cost, need for assembly, material waste, and ignored fatigue performance. These drawbacks mean that a huge portion of the CFMM design space remains untouched. To address these challenges, a methodologic breakthrough is required that seamlessly integrates the four pillars of CFMM development: material, modelling, design, and manufacturing.

Hyper-ThermoVisco-Pseudoelastic (HTVP) materials like Thermoplastic Polyurethane (TPU) have a nonlinear stress-strain behaviour and possess an inherent energy dissipation capability with excellent toughness and cyclic fatigue resistance. Employing the inherent energy dissipation feature of HTVP materials and unique behaviour of CFMMs along with advances in 3D printing can realise CFMMs with tailorable static and dynamic properties and open a vast design space meeting desired characteristics. This project aims to exploit inherent energy dissipation features of HTVP materials and develop an Integrated Material-Modelling-Manufacturing paradigm to create a new class of Mechanical metamaterials so-called Meta-regulators (i.e., I5M) with minimal computational cost, material usage and expert interference.

I5M will break new ground by creating and exploiting breakthroughs in HTVP materials with variable soft-to-stiff properties, triaxial normal-shear constitutive modelling, physics-informed machine learning for evolutionary inverse design, and sustainable 3D printing. I5M technology will represent a fundamentally new field of sustainable metamaterials paradigm and create passive HTVP meta-regulators with built-in functionalities such as with programmable quasi-zero stiffness, quasi-constant force regulation, tuneable vibration isolation and fatigue resistance. I5M will minimise the expert interference, for example, I5M will simply receive constant force-displacement response and vibration transmissibility as input, determine optimum material and geometrical parameters, and then 3D print a meta-regulator meeting those requirements. I5M will validate HTVP meta-regulators functionality via 4 demonstrators for healthcare, automotive, aerospace and sport industries.