Chao Gao

Norwegian University of Science and Technology | NTNU · Department of Mechanical and Industrial Engineering

Developing accurate yet fast computational tools to simulate complex physical phenomena is a long-standing problem. Recent advances in machine learning have revolutionized the way simulations are approached, shifting from a purely physics- to AI-based paradigm. Although impressive achievements have been reached, efficiently predicting complex physi...

The introduction of 4D printing has revolutionized the concept of additive manufacturing; it is a promising technology that can bring immense advantages over classical production and manufacturing techniques, such as achieving programmed time-varying structures and consequently reducing production time and costs. The rise of 4D technology is consid...

Fatigue is the most common failure mode for engineering materials in various industrial applications. Generally, designing new products and components based on typical deterministic fatigue design approaches is slow and expensive. Although numerous investigations have been carried on this topic over decades, there still lacks a robust and efficient...

Manipulating the architecture of materials to achieve optimal combinations of properties (inverse design) has always been the dream of materials scientists and engineers. Lattices represent an efficient way to obtain lightweight yet strong materials, providing a high degree of tailorability. Despite massive research has been done on lattice archite...

Exploiting small scale material effects and structural topology, nano-architected lattices represent a recent novel class of mechanical metamaterials, which exhibit unprecedented combination of mechanical properties. Together with scarce resistance to fracture and catastrophic failure, understanding of the fracture characteristics and properties of...

Over the last decades, 3D printing has found applications in all areas of engineering, ranging from electronics to biomedical industries, due to its efficiency in the use of the material in terms of mass customization and waste reduction and its high resolution and precision during the prototyping stage. Nevertheless, while the traditional additive...

Fatigue is a common failure mode in ship structures. For structures with an initial crack, the fatigue crack propagation behavior needs to be considered. The purpose of this study is to establish a procedure for analysis of fatigue crack propagation of ship structures in combination with reliability methods. The stress intensity factor (SIF) and ge...

Biological structural systems such as plant seedcoats, beak of woodpeckers or ammonites shells are characterized by complex wavy and re-entrant interlocking features. This allows to mitigate large deformations and deflect or arrest cracks, providing remarkable mechanical performances, much higher than those of the constituent materials. Nature-insp...

As one of the additive manufacturing (AM) methods, fused deposition modeling (FDM) technology is widely adopted but involves some limitations in lacking surface quality and mechanical properties due to the use of only planar layers. This review will explore the novel FDM approach, curved layer FDM (CLFDM) where a nonplanar slicing technique is intr...

The main aim of the current study is to evaluate the compressive quasi‐static and fatigue properties of titanium alloy (Ti6Al4V) cellular materials, with different topologies, manufactured via laser powder bed fusion (LPBF) process. The topologies herein considered are lattice‐based regular and irregular configurations of cubic, star, and cross‐sha...

The main aim of the current study is to evaluate the compressive quasi-static and fatigue properties of titanium alloy (Ti6Al4V) cellular materials, with different topologies, manufactured via Laser Powder Bed Fusion (LPBF) process. The topologies herein considered are lattice based regular and irregular configurations of cubic, star and cross shap...

In article number 1908242, Ling Li and co‐workers provide a mechanistic understanding of crack formations during the evaporation‐induced self‐assembly of colloidal crystals, which allows for rational controlling of the location and orientation of cracks for fabricating photonic microstructures with controlled geometries and sizes.

Evaporation‐induced self‐assembly of colloidal particles is one of the most versatile fabrication routes to obtain large‐area colloidal crystals; however, the formation of uncontrolled “drying cracks” due to gradual solvent evaporation represents a significant challenge of this process. While several methods are reported to minimize crack formation...

We investigate the influence of raster layup on the resulting material properties of FDM 3D-printed materials made of PLA. In particular, we investigate the resulting toughness, strength, and stiffness, with a special focus on toughness. We show that for standard layups with layer orientations alternating by 90°, stiffness and strength are almost i...

Common millet (Panicum miliaceum) seed is a prevalent crop worldwide with high adaptability and survivability. The outer seedcoat of common millet seed has an interesting and complex microstructure, with epidermal cells being articulated with wavy sutures, to form a jigsaw-like sutural tessellation. Experimental flatwise compression tests were perf...

Architectured materials have attracted much attention in recent years because the specific micro‐nano structure and material combinations of architectured materials can lead to very high performance structures. Topological interlocking material (TIM), as one type of dense architectured materials, shows outstanding performances in mechanical propert...

Inspired by the wavy sutural tessellations in the seed coats of flowering plants, in article number 1800579, Yaning Li and co‐workers explore a new design concept for mutually amplifying strength and toughness in tiled composites. By tuning the waviness and material contrast of the suture tessellation, the composites can also exhibit negative Poiss...

Architectured composites with sutural tessellations across all length scales are found in the armor systems of many fauna and flora species in nature. These composites are typically composed of relatively stiff building blocks articulated via compliant wavy suture seam, showing a remarkable jigsaw-puzzle-like sutural tessellation. Inspired by these...

Instability-induced pattern transformations of the architectured multi-phase soft metamaterial under bi-axial compression were explored. The soft metamaterial is composed of two phases: a soft matrix and a reinforcing hexagonal network embedded in the matrix. Equi-biaxial loading is found to induce both micro- and macro- instabilities in the networ...

Protective armors are widespread in nature and often consist of periodic arrays of tile‐like building blocks that articulate with each other through undulating interfaces. To investigate the mechanical consequences of these wavy tessellations, especially in instances where the amplitude of the undulations is near the scale of the constituent tiles...

Surface patterns can be used as a selective coating platform on metal surfaces, in particular, under various deformation conditions because they induce local strain gradients along with pattern geometry. In this study, hard and flexible coating materials were introduced to regions with small and large deformations, respectively, on patterned magnes...

Panicum Miliaceum (common millet) is an ancient crop and spread widely across the world. The high survivability and adaptability of this species is attributed to the unique structure of the seedcoat. Recently, it was found the seedcoat has a fascinating complex microstructure with star-shaped epidermis cells, articulated together via wavy suture in...

The common millet (Panicum miliaceum) seedcoat has a fascinating complex microstructure, with jigsaw puzzle-like epidermis cells articulated via wavy intercellular sutures to form a compact layer to protect the kernel inside. However, little research has been conducted on linking the microstructure details with the overall mechanical response of th...

In this investigation, the mechanical response of a tri-phase system subjected to far-field compression is explored. The system includes a stiffer interfacial/coating layer surrounded by an interphase/regulation layer, and both layers are embedded in an infinite softer matrix. Both theoretical and finite element (FE) mechanical models of the system...