Experiments have been performed to demonstrate that ultrasound in the 100–400 kHz frequency range can be used to propagate signals through various types of industrial insulation. This is despite the fact that they are highly attenuating to ultrasonic signals due to scattering and viscoelastic effects. The experiments used a combination of piezocomposite transducers and pulse compression processing. This combination allowed signal-to-noise levels to be enhanced so that signals reflected from the surface of an insulated and cladded steel pipe could be obtained.

Rheology plays a critical role across science and engineering, affecting sectors from healthcare to energy. In the UK, rheological research supports innovation in both academia and industry. This review, coordinated by the British Society of Rheology (BSR), provides an updated overview of current research directions across the UK and beyond.

Acoustic metamaterials constructed from conventional base materials can exhibit exotic phenomena such as negative refractive index, extraordinary transmission-absorption and sub-wavelength imaging. These are typically achieved by combining geometrical and resonance effects. Holey-structured acoustic metamaterials have already shown potential for sub-wavelength acoustic imaging in air, where it is relatively simple to achieve the required difference in acoustic impedance needed to create resonances within the holes. However, the use of polymers for metamaterial operation in water is difficult, due to the much lower difference in acoustic impedance between water and the many polymers used, for example, in additive manufacturing. Hence, metals are commonly used. Here we show that this can be overcome by trapping air layers so that they surround each water-filled channel, making sub-wavelength imaging in water possible. The operation of such a Trapped air design is confirmed at 200-300 kHz ultrasonic frequencies via both finite element modelling and experimental measurements in a water tank. It is also shown quantitatively that the trapped air design outperforms its metal counterpart. The results indicate a way forward for exploiting additive-manufacturing for realising acoustic metamaterials in water at ultrasonic frequencies.

Metamaterials provide exceptional properties arising from their well-defined engineered structures in which periodic features ranging from the nanoscale to the macroscale are manufactured to yield the desired characteristics. Recent advances in manufacturing techniques have dramatically expanded the design space and potential applications of metamaterials. Progress in high-resolution additive processes, scalable subtractive techniques, and emerging hybrid and formative approaches has enabled architectures that were previously difficult to realise at meaningful scale. Although challenges remain for scaling production, recent advances are moving metamaterials beyond laboratory-scale demonstrators towards more manufacturable platforms. These developments suggest emerging – though still early – pathways for broader technological deployment, enabling new possibilities for multifunctional devices, large-area metasurfaces, and mechanically robust architected materials. This roadmap explores the current-state-of-the art manufacturing techniques for metamaterials, highlighting key challenges and opportunities in scaling-up production and commercialisation, and outlines potential strategies for overcoming the barriers that currently limit large-scale implementation.