Hong Kong University of Science and Technology (HKUST) scientists have created a new class of soft composite materials with highly programmable, asymmetric mechanical responses, marking a significant advance toward mechanical intelligence.
Led by Prof. XU Qin from the Department of Physics and Prof. HU Wenqi from the Department of Mechanical and Aerospace Engineering, the research leverages shear-jamming transitions to enable direction-dependent behaviors crucial for next-generation soft robotics and smart devices.
Imagine a material that stiffens when pushed from one direction but remains soft when pressed from another, or a soft robot that can navigate tight spaces by controlling its shape and movement with precision.
This is the promise of mechanical intelligence, where materials themselves can compute and respond to their environment without complex electronic controls. For years, achieving such directional control in soft materials has relied on complex metamaterial structures that are often brittle and prone to failure. The HKUST team’s breakthrough offers a more robust and programmable alternative.
READ ALSO: https://www.modernmechanics24.com/post/juno-ghost-particle-discovery
The key innovation lies in integrating shear-jamming transitions—a phenomenon where granular materials suddenly stiffen under shear stress—into compliant polymer solids. This creates soft composites that exhibit non-reciprocal behaviors, meaning they respond differently depending on the direction of force.
“By leveraging shear-jamming, we can program asymmetric mechanical responses directly into the material’s fabric,” explained Prof. XU Qin. This approach allows the materials to exhibit directional shape memory and controlled stiffness changes, capabilities previously difficult to achieve in a single, defect-tolerant system.
What makes these composites particularly remarkable is their multi-directional control. They can exhibit asymmetric responses in both shear and normal directions simultaneously, a feature that enables sophisticated functions like one-way shape morphing and directional energy absorption.
WATCH ALSO: https://www.modernmechanics24.com/post/isro-gaganyaan-crew-parachute-validation
Unlike conventional metamaterials that rely on precise structural arrangements and fail catasthetically when damaged, these shear-jammed composites are remarkably fracture-resistant. Their mechanical properties can be tailored across multiple scales, making them suitable for diverse applications from synthetic tissues to flexible electronics.
The team didn’t stop at passive materials. By embedding these structures with spatially-modulated magnetic profiles, they created what they call “active soft solids.” These materials can perform directional motion when exposed to magnetic fields, functioning as bio-inspired soft robots. In demonstrations, these active composites navigated confined environments and acted as smart valves in microfluidic systems, allowing selective flow control without external power or complex mechanisms, reported the research team.
From a scientific perspective, this work bridges granular physics and polymer science, creating a new category of non-reciprocal soft materials. The shear-jamming transition provides a reversible phase change that can be precisely controlled, offering a versatile design parameter for engineers.
READ ALSO: https://www.modernmechanics24.com/post/ai-data-centers-solo-reactor-100-unit-plan
“We’re not just making a new material; we’re establishing a new design paradigm for mechano-intelligent systems,” stated Prof. HU Wenqi. This paradigm shift could lead to materials that adapt, learn, and respond to their environments, embodying a form of embedded intelligence.
The potential applications are vast. In soft robotics, such materials could enable robots that move through debris or narrow passages with animal-like agility. In biomedical engineering, they could create synthetic tissues that respond mechanically to physiological changes. For flexible electronics, they could provide protective, direction-sensitive substrates that shield components from specific impact directions while remaining compliant to others.
This research represents a critical pathway toward true mechanical intelligence—materials and systems that process mechanical information and respond appropriately without external computation.
WATCH ALSO: https://www.modernmechanics24.com/post/uae-first-domestic-drone-maiden-flight
The HKUST team’s work demonstrates that by breaking mechanical symmetry through shear-jamming, we can create soft materials that are not just passive substances but active participants in smart, energy-efficient systems. As this technology develops, we may see a new generation of devices that interact with their world as intelligently as living organisms do.
