research

ttps://onlinelibrary.wiley.com/doi/full/10.1002/adfm.201806698

Fast‐Response, Stiffness‐Tunable Soft Actuator by Hybrid Multimaterial 3D Printing

Yuan-Fang Zhang, Ningbin Zhang, Hardik Hingorani, Ningyuan Ding, Dong Wang, Chao Yuan, Biao Zhang, Guoying Gu,* and Qi Ge*

I hope some of you may find this work interesting. We show that kinematic hardening effects play a significant role in monotonic/static fracture.

Steady-state fracture toughness of elastic-plastic solids: Isotropic versus kinematic hardening

K.J.Juul, E.Martínez-Pañeda, K.L.Nielsen, C.F.Niordson

Engineering Fracture Mechanics, 207, pp. 254-268 (2019)

Volume 207, 15 February 2019, Pages 254-268

In this manuscript with Lev Truskinovsky, we developed a new nonlinear theory of large-strain incompatible surface growth. Surface growth is a crucial component of many natural and artificial processes from cell proliferation to additive manufacturing. In elastic systems, surface growth is usually accompanied by the development of geometrical incompatibility leading to residual stresses and triggering various instabilities. Here we developed a nonlinear theory of incompatible surface growth which quantitatively linkes deposition protocols with post-growth states of stress.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.255304

Accelerated Search and Design of Stretchable Graphene Kirigami Using Machine Learning

P.Z. Hanakata, E.D. Cubuk, D.K. Campbell and H.S. Park

In this progress report, we reviewed recent advances in strategies for applying mechanical strain into 2D materials and recent state‐of‐the‐art characterizations of interface mechanics for 2D material–substrate systems.

Pumps are critical life-sustaining components for all animals. At the earliest stages of life, the tubular embryonic heart works as a valveless pump capable of generating unidirectional blood flow. Inspired by this elementary pump, we developed the first example of a biohybrid valveless pump-bot powered by engineered skeletal muscle. Our pump-bot consists of a soft hydrogel tube connected at both ends to a stiffer polydimethylsiloxane (PDMS) scaffold, creating an impedance mismatch.

The anomalous propagation of short cracks shows generally exponential fatigue crack growth but the dependence on stress range at high stress levels is not compatible with Paris’ law with exponent m=2. Indeed, some authors have shown that the standard uncracked SN curve is obtained mostly from short crack propagation, assuming that the crack size a increases with the number of cycles N as da/dN=H\Delta\sigma^h where h is close to the exponent of the Basquin’s power law SN curve.

Shape memory ceramics are a unique family of shape memory materials with a wide variety of applications, such as ultra-high energy dissipation and high-temperature actuation. Along with significant progress in the experimental study of zirconia-based shape memory ceramics in recent years, computational simulations have exhibited powerful capabilities in revealing nano/microstructure-dependent deformation and failure mechanisms in these materials.