Geometric effects on impact mitigation in architected auxetic metamaterials

Lightweight materials used for impact mitigation must be able to resist impact and absorb the maximum amount of energy from the impactor. Auxetic materials have the potential to achieve high resistance by drawing material into the impact zone and providing higher indentation and shear resistance. However, these materials must be artificially...

A low-fidelity model for the dynamic analysis of full-lattice wind support structures

This work aims to develop a low-fidelity model for a lattice support structure for offshore wind applications. The proposed low-fidelity model consists of a sequence of regular Timoshenko beams, each of them characterized by homogenized mechanical and mass properties representative of the single bays of the reference space-frame structure....

GNNs and Beam Dynamics: Investigation into the application of Graph Neural Networks to predict the dynamic behaviour of lattice beams

In the past decade, the application of Neural Networks (NNs) has received increasing interest due to the growth in computing power. In the field of computational mechanics, this has led to numerous publications presenting surrogate models to assist or replace conventional simulation methods. A subset of these networks, referred to as Graph...

Toolpath Generation for Fused Filament Fabrication of Functionally Graded Materials

The products in our day to day lives have different requirements in different regions of the product. One way of dealing with such spatially varying requirements is to divide the product into multiple parts and assign each part a different material. For example, the handle of a drill is often fitted with a rubbery material which gives it more...

ITIL: Interlaced Topologically Interlocking Lattice for continuous dual-material extrusion

Material Extrusion (MEX) systems with dual-material capability can unlock interesting applications where flexible and rigid materials are combined. When chemically incompatible materials are concerned the adhesion between the two might be insufficient. Therefore researchers typically rely on dovetail type interlocking geometries in order to...

Numerical and Experimental Study of Quasi-Static Loading of Aluminum Closed-Cell Foams Using Weaire–Phelan and Kelvin Tessellations

Study of porous materials, in particular closed-cell foams, has always attracted researchers’ interest due to the advantages these materials offer in applications where low weight, buoyancy, insulation, or energy absorption is of importance. In this study, quasi-static compressive experimental tests are conducted for low-, medium-, and high...

Thermal process modelling of lattice structures during selective laser melting process

As a type of powder-bed-based Additive Manufacturing (AM), Selective Laser Melting (SLM) is widely used for building metallic lattice structures. However, during SLM process, geometrical imperfections and defects, such as strut over-sizing or under-sizing, typically exist in components due to overheating, which strongly influence their...

Modularity in Lattice structures for Circular Product Design

The principles of repair and maintenance, reuse, and repurposing of products in a circular economy aim at further minimizing the environmental impact during the use of products before being processed for recycling. However, studies on lattice structures in various fields focus on mechanical characteristics, design, and manufacturing methods....

Design of a Scalable Automated Manufacturing Method for Composite Iso-truss Structures

The IsoTruss is an interesting continuous fibre reinforced polymer composite design which is closely related to open lattice composite structures, although it is currently aimed mostly at civil applications. While it currently lacks applicability to the aerospace sector, its production process is easier to automate (or change the shape input...

Design and Optimization of Conforming Lattice Structures

Inspired by natural cellular materials such as trabecular bone, lattice structures have been developed as a new type of lightweight material. In this paper we present a novel method to design lattice structures that conform with both the principal stress directions and the boundary of the optimized shape. Our method consists of two major...

A novel design of multi-stable metastructures for energy dissipation

Multi-stable metastructures composed of curved beams can switch to a series of stable configurations via elastic snap-through transitions. The elastic deformations allow metastructures to function as reusable energy absorbers. However, conventional metastructure designs based on solid beams often result in relatively low energy dissipation....

Dynamic crushing behavior of closed-cell aluminum foams based on different space-filling unit cells

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Learning from Nature's Failures: Mimicking Hierarchy in Natural Structures to Create Damage-Tolerant Lattice Materials

To create a more sustainable future for aviation, new, lighter-weight structures and materials will need to be engineered. It will also be critical that damage tolerance and safety are not compromised in the process. Lattice materials represents one avenue of exploration; however, two key challenges arise: limited experimental work has been...

Repairability of lattice structure in a circular economy: Mechanical response of 3D printed octet-truss lattice structures under quasi-static loading

Repair and maintenance of products require few resources in a circular economy, minimising the environmental impact of manufacturing and use of products. Although lightweight lattice structures have been widely investigated in various fields owing to their advantages in terms of their mechanical characteristics and the development of additive...

Non-auxetic mechanical metamaterials

The concept of "mechanical metamaterials" has become increasingly popular, since their macro-scale characteristics can be designed to exhibit unusual combinations of mechanical properties on the micro-scale. The advances in additive manufacturing (AM, three-dimensional printing) techniques have boosted the fabrication of these mechanical...

Fracture Toughness of Aerospace Structures: On the Use of Redundant Lattice Structures

Both experimental and numerical studies have shown that the crack-bridging is one of the most significant mechanism contributing to the fracture toughness of natural materials like nacre and bone. This study aims to explore if additive manufactured lattice structures can be used to bridge fatigue cracks as well, thereby improving the fracture...

Simplified Fatigue Assessment of Offshore Wind Turbine Full Height Lattice Structures in the Frequency Domain

New concepts for support structures of offshore wind turbines have gained interest in the industry and are examined for intermediate and deep water depths in order to unlock new offshore potential markets. One of the main proposals that has already been commercialized is the three or four leg full height lattice structure. The fatigue assessment...

Operational Vibration-Based Response Estimation for Offshore Wind Lattice Structures

The design for fatigue for offshore wind turbine structures is characterized by uncertainty, resulting from both loading specifications and numerical modelling. At the same time, fatigue is a main design driver for this type of structures. This study presents a strategy to monitor the accumulated fatigue damage in real-time, employing a joint...