research

Have you ever though about what make composite materials fail under cyclic loading? In the paper we collect evidence of what is fatigue damage actually is. We combine the collected clues into a conceptual model for fatigue damage in unidirectional composites. Next, we formulate a mathematical micromechanical model. The model can predict the fatigue life of a unidirectional fibre composites from the basic mechanics properties of the fibre, matrix and the fibre/matrix interface.

Dear colleagues,

The Frontiers in Robotics and AI has launched a new Research Topic, Soft Robotics based on Liquid Crystal Elastomers (LCEs). 

The submission deadline is 19 January 2022.

Here is the homepage for this research topic:

https://www.frontiersin.org/research-topics/23109/soft-robotics-based-on...

As a contributing author, you will benefit from:

I bring to your attention this opportunity at the University of L'Aquila.

Kindest regards,
Giuseppe 

We report phenomenal yield strengths—up to one-fourth of the theoretical strength of silver—recorded in microcompression testing of initially dislocation-free silver micro- and nanocubes synthesized from a multistep seed-growth process. These high strengths and the massive strain bursts that occur upon yield are results of the initially dislocation-free single-crystal structure of the pristine samples that yield through spontaneous nucleation of dislocations.

We introduce a class of parity-time symmetric elastodynamic metamaterials (Ed-MetaMater) whose Hermitian counterpart exhibits unfolding (fractal) spectral symmetries. Our study reveals a scale-free formation of exceptional points in those Ed-MetaMaters whose density is dictated by the fractal dimension of their Hermitian spectra.

The non-transforming intermetallic Ni3Ti phase generated in NiTi matrix by additive manufacturing was previously reported to create elastocaloric composites with a great coefficient of performance (COP) between 11 and 22 [Hou et al., Science 366 (6469) (2019) 1116–1121]. In this work, we use a fully thermomechanical coupled phase-field model to design microarchitectures with very high COP considering the effects of all the possible non-transforming intermetallics (Ni4Ti3, Ni3Ti, and Ti2Ni) in NiTi.

Studying fatigue properties of small specimens can be challenging, yet is needed for research purposes as well as for product and verification testing in industries like the medical device and additive manufacturing.

Fatigue testing allows manufacturers and researchers to get a critical understanding of how a material or component will perform in real-world loading scenarios over the course of time. Common fatigue testing definitions and keywords include:

Surfaces showing macroscopic adhesion are rare in industry, but are abundant in Nature. Adhesion enhancement has been discussed mostly with geometrical systems (e.g. patterned surfaces), more rarely with viscoelasticity, and has the goal of increasing hysteresis and the detachment force at separation. Soft materials are common, and these have viscoelastic properties that result in rate-dependent increase of toughness.

We present a theory for finite and spatial elastic deformation of rods under the influence of arbitrary magnetic field and boundary condition. The rod is modeled as a Kirchhoff rod and is assumed to have uniformly distributed array of uniaxial spheroidal paramagnetic inclusions embedded in it all pointing in the same direction in the undeformed state. The governing equations of the magnetoelastic rod are derived which are further non-dimensionalized and linearized to investigate buckling in such rods.

We are soliciting article submissions for a special issue on Advances in Computational and Data-driven Poromechanics for International Journal of Multiscale Computational Engineering

Wrinkling is one of the most important mechanical deformation modes (for example, buckling and crumpling) that are omnipresent in our daily life: for instance, wrinkled fingers after soaking in water for a prolonged time, the folds within the brain, and metal wrinkles after a car collision, to name a few.

By Yuzhen Chen, Lihua Jin

Self-assembly of three-dimensional (3D) structures, through bending, twisting, folding, and buckling, has garnered broad interest among physicists, mathematicians, chemists, and biologists. Herein strain engineering and geometric frustration as an on-demand strategy for fabricating spontaneous rolling “origami” structures with programmable multistability across multiple length scales are exploited.

The design of a dynamic, versatile, convertible, and responsive micropatterned system is realized by a photo/moisture reconstructible multiscale film-substrate bilayer structure. Specifically, a hydrophilic polyvinyl alcohol (PVA)/laponite (LP) thin film is covalently bonded to a photothermally active polydimethylsiloxane (PDMS)/carbon black (CB) soft substrate. A laser engraver can inscribe programmable aligned micro-wrinkles by manipulating laser power and spatiotemporal control.

Check out our paper at Materials Today: https://www.sciencedirect.com/science/article/abs/pii/S1369702120304491