Fei Pan

Beihang University (BUAA) | BUAA · School of Aeronautical Science and Engineering

Metamaterials have unprecedented properties that facilitate the development of advanced devices and machines. However, their interconnected building structures limit their applications, especially in the fields that require large deformation, rich programmability and efficient shape‐reconfigurability. To break this limit and exploit more potentiali...

Re-customizable mechanical behavior is critical for versatile materials with tunable functions and applications, but inverse design for varying targets is often hindered by complex coupling between structural topologies and mechanics. In this work, a novel “stair-building” strategy for customizing as well as re-customizing target mechanical behavio...

Proactively programming materials toward target nonlinear mechanical behaviors is crucial to realize customizable functions for advanced devices and systems, which arouses persistent explorations for rapid and efficient inverse design strategies. Herein, we propose a "mechanical Fourier transform" strategy to program mechanical behaviors of materia...

Fast shape-reconfiguration with large morphing amplitude is crucial for intelligent materials/structures that require tunable functions and adaptivity to different environments. However, the morphing strategies are rare in combining ultrafast speed, large amplitude, and high energy-efficiency simultaneously. Herein, a class of 2D and 3D chiral mech...

Nanofiber networks are effective structural forms to utilize the excellent nanoscale properties of nanofibers in macro scale. Properly tuning the anisotropic degree of fiber orientation distribution can maximize the macroscopic mechanical properties of random nanofiber networks in a specific direction. However, the reinforcing mechanism of the anis...

Rationally tuning the anisotropic degree of orientation distribution for conductive fibers in composites can maximize the macro electrical conductivity in a specific direction. However, quantitative evaluation of the optimum anisotropic degree of networks with fibers of different shapes and orientation distributions remains largely unexplored. In t...

Metallic thin-walled tube systems are widely used in the field of impact protection. In particular, self-locked systems can be rapidly assembled for emergent energy absorption without the need of additional constraints. However, most of the existing self-locked systems are inspiration-based, indicating the lack of unified design guidance for self-l...

Fiber aggregation in nanocomposites has an important effect on macroscopic electrical performance. To quantitatively evaluate its effect, an index to characterize the degree of aggregation is imperative and, ideally, it should have three features simultaneously, i.e., (1) single-parametric, dimensionless, and physically meaningful, (2) applicable t...

Increasing energy and space utilization efficiency is crucial for lightweight shape-reconfigurable materials/structures that require tunable functions and multiple applications. Mechanical multistable origami/kirigami structures can improve the controlling stability and energy utilization efficiency of shape-reconfiguration. However, their scalabil...

Fiber aggregation in nanocomposites has an important effect on the macroscopic electrical performance. To quantitatively evaluate its effect, an index to characterize the degree of aggregation is imperative, and ideally it should have three features simultaneously, i.e., single-parametric, dimensionless and physically meaningful, applicable to diff...

The mechanical properties of most impact-resistant devices cannot be flexibly adjusted after manufacture to adapt to complex engineering requirements. Honeycombs are widely used due to excellent crash performance, while sharp initial peak stress under out-of-plane impacts results in great damage, and their in-plane bearing capacity is significantly...

Plate-like sheet networks assembled by randomly distributed sheets are commonly found in artificial nacre-like materials. However, the effects of spatial randomness and porosity of the network on its mechanical properties still remain largely unrevealed. To make a comprehensive understanding on the elasticity of these networks, a mechanics model is...

Plate-like lattice structures have attracted increasing attention due to their excellent structural and functional properties. As the basis of applications, their in-plane and out-of-plane stiffness, especially the mechanism of out-of-plane deformation, still remain insufficiently understood. For a comprehensive understanding of their mechanical be...

Reconfiguring to complex 3-dimensional (3D) target shapes from an easily-manufactured low dimensional initial configuration is crucial for many versatile materials/structures which require tunable functions and multiple applications. However, the energy-efficient morphing strategy to realize such transdimensional shape-reconfiguration remains large...

Re-Customizable Metamaterials In article number 2101808, Fei Pan, Yuli Chen, and co-workers develop a “stair-building” strategy for customizing and re-customizing targeted mechanical behaviors for mechanical metamaterials. Similar to building a stair with bricks, a targeted stress-strain curve can be realized by stacking the brick-shaped loading cu...

Stronger, tougher, and lighter materials are always among the relentless pursuits of material scientists and engineers. The hierarchical design inspired by nature has been considered as one of the most promising strategies to improve the mechanical properties and functionalities of synthetic materials beyond their present limitations. Therefore, th...

Finlets have a unique overhanging structure at the posterior, similar to a flag. They are located between the dorsal/anal fin and the caudal fin on the dorsal and ventral sides of the body. Until now, the sensing ability of the finlets is less understood. In this paper, we design and manufacture a biomimetic soft robotic finlet (48.5mm in length, 3...

We report the fabrication of an exotic bamboo‐like π‐nanotube via the hierarchical self‐assembly of a dipeptide‐substituted naphthalenediimide gelator with tunable helicity and circularly polarized luminescence (CPL). It was found that in the presence of trifluoroacetic acid (TFA) the gelator molecule self‐assembled into a bamboo‐like nanotube, whi...

The 2D nanosheets hierarchical assembled into diverse bamboo-like π-nanotube with tunable helicity by a „bottom-up“ route. The diameter ratio of the upper to lower edge of each stacking truncated nanocone (RH) can be regulated to express the different helicity of the nanotube. The chiroptical nanoarchitectures show an enhanced and RH-dependent adju...

Nature has evolved to shape morphing to adapt to complex environments while engaging with the surroundings. Inspired by this capability, robots are expected to be endowed with the ability to perform shape‐changing, thus interacting with complex environments. Herein, a soft origami actuator with variable effective length (VEL) is proposed to adapt t...

3D-printed flexible tensegrities with metamaterial properties enable customizable complex locomotion in soft robots.

2-dimensional (2D) random fiber networks are extremely thin plate-like structures constructed by randomly distributed fibers, and have been widely used in many fields from nano to macro scales due to their excellent properties. To make a comprehensive understanding on their in-plane and especially out-of-plane elastic properties, a mechanics model...

For thin networked materials, which are spatial discrete structures constructed by continuum components, a paradox on the effective thickness defined by the in-plane and out-of-plane stiffnesses is found, i.e. the effective thickness is not a constant but varies with loading modes. To reveal the mechanism underneath the paradox, we have established...

Transfer of molecular chirality to supramolecular chirality at nanoscale and microscale by chemical self-assembly has been studied intensively for years. However, how such molecular chirality further transfers to the macroscale along the same path remains elusive. Here we reveal how the chirality from molecular level transfers to macroscopic level...

The performances of graphene sheets in nano-devices strongly depend on their morphology, which can be changed enormously by the nanoscale asperities of the substrate. Therefore, it is of great importance to predict morphologies of graphene supported by substrates with different rough surfaces and non-developable curved surfaces. To study the morpho...

Stability is an important problem in applications of plate and shell structures as well as newly arisen nano-structures, such as nanotubes and graphene sheets. Most classical methods for stability analysis require buckling modes, which are difficult to be accurately predicted, especially for the structures with complex boundary boundaries and load...

Carbon nanotube (CNT) films are easily bent in their applications because the dimension in thickness is much smaller than the other two dimensions. Therefore, it is of great importance to understand the bending mechanisms and to predict the bending stiffness of CNT films. In this paper, the out-of-plane bending stiffness of CNT films is studied bas...

The buckling of graphene sheets on substrates can significantly degrade their performance in materials and devices. Therefore, a systematic investigation on the buckling behavior of monolayer graphene sheet/substrate systems is carried out in this paper by both molecular mechanics simulations and theoretical analysis. From 70 simulation cases of si...

The electrical percolation of polymer-matrix composites (PMCs) containing hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinde...