research

By Tianzhen Liu, Yuzhen Chen, John W. Hutchinson, Lihua Jin

Graphical Abstract (from Publication 2 below):

Abstract:

Liu, M., Domino, L., de Dinechin, I. D., Taffetani, M., & Vella, D.* (2023). Snap-induced morphing: From a single bistable shell to the origin of shape bifurcation in interacting shells. J Mech. Phys. Solids, 170, 105116.

In this paper we formulate the initial-boundary value problem of accreting circular cylindrical bars under finite torsion. It is assumed that the bar grows as a result of printing stress-free cylindrical layers on its boundary while it is under a time-dependent torque (or a time-dependent twist) and is free to deform axially. In a deforming body, accretion induces eigenetrains, and consequently residual stresses. We formulate the anelasticity problem by first constructing the natural Riemannian metric of the growing bar.

Yijie Cai, Jie Ma, Zihang Shen, Xianmin Shao, Zheng Jia *, Shaoxing Qu, Enhancing the fracture resistance of hydrogels by regulating the energy release rate via bilayer designs: Theory and experiments, Journal of the Mechanics and Physics of Solids, 170, 105125 (2023) 

Multiscale mechanics and extreme materials lab (https://z.umn.edu/ravi-research-lab) at the University of Minnesota Twin Cities has two fully funded Ph.D. positions starting in fall 2023. Interested candidates may reach out to sravi@umn.edu.

For orthotropic plane strain problems, the various existing calculation methods are very complex. The orthotropic plane strain problem with cracks have solved by using a new element model, and compared with the finite element method, it can be found that the displacements and the stresses of the two methods are in good agreement.
Supplemental Videos:
(1) https://www.bilibili.com/video/BV1QW4y1e7YQ/?spm_id_from=333.999.0.0

The plane stress problems have solved by using a new orthotropic element model, compared with the finite element method, it can be found that the results of the two methods are in good agreement.
Supplemental Videos:
(1) https://www.bilibili.com/video/BV1yd4y167i6/?spm_id_from=333.999.0.0
(2) https://www.bilibili.com/video/BV1CV4y1M7y6/?spm_id_from=333.999.0.0

This work presents a modified phase-field model for accurate coupling of phase transformation and cracking in shape memory ceramics. The existing phase-field models underestimate the elastic response at the beginning of the mechanical response. We modified the chemical free energy to control the rate of phase transformation and consequently obtain a physical elastic response before initiation of phase transformation. First, the forward and reverse martensitic phase transformation in a superelastic single crystal 3 mol% yttria-stabilized tetragonal zirconia is studied.

Dear Colleagues,

I invite you to read our recent paper on hierarchically architected foams published in Extreme Mechanics Letters: Read full article here.

Abstract

Meng, Z., Liu, M., Yan, H., Genin, G. M., & Chen, C. Q.* (2022). Deployable mechanical metamaterials with multistep programmable transformation. Science Advances, 8(23), eabn5460.

Mao, J. J.*, Wang, S., Tan, W.*, & Liu, M.* (2022). Modular multistable metamaterials with reprogrammable mechanical properties. Engineering Structures, 272, 114976.

Zhang, Y., Yang, J., Liu, M.*, & Vella, D. (2022). Shape-morphing structures based on perforated kirigami. Extreme Mechanics Letters, 56, 101857.

In this paper we discuss nonlinear anisotropic anelasticity formulated based on the two multiplicative decompositions F=FeFa and F=FaFe. Using the Bilby-Kroner-Lee decomposition F=FeFa one can define a Riemannian material manifold (the natural configuration of an anelastic body) whose metric explicitly depends on the anelastic deformation Fa.

Dear Colleagues, Our recent publication on the Journal of Applied Mechanics:

https://doi.org/10.1016/j.jmps.2022.105031

Abstract