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Can someone post an example of UMAT and VUMAT for the same elasto-plastic problem?

Submitted by rctron on

I want to understand how the stress update algorithm is modified for the different definitions of stress rate in ABAQUS/Standard and ABAQUS/Explicit formulations. I know the relationships, I just want to see how it's coded in a subroutine.

Also, the Hughes-Winget algorithm is used to update the stress defined by the Green-Naghdi stress rate by using the Jaumann rate. How to implement that in VUMAT? Can someone please post an example to clarify these aspects?

EML Webinar by Stephanie Lacour on July 8, 2020: From engineering elasticity to neural implants for translational research

Submitted by Teng Li on

EML Webinar on July 8, 2020 will be given by Prof. Stephanie Lacour at EPFL via Zoom meeting. Discussion leader: Professor Sigurd Wagner, Princeton University

Title: From engineering elasticity to neural implants for translational research

How to include temperature effects on the shear rates in Dr. Huang's crystal plasticity code

Submitted by rctron on

I am using Dr. Huang's crystal plasticity code for an adiabatic process where temperature increase due to deformation need to be calculated. Dr. Huang's CP UMAT code does not consider the temperature effect of shear rate or hardening. Is there a way to include temperature effects in the current UMAT code?

http://www.columbia.edu/~jk2079/Kysar_Research_Laboratory/Single_Crysta…

Thermal wrinkling of liquid crystal polymer shell/core spheres

Submitted by Fan Xu on

Smart soft materials that can flexibly respond to external multi-physics stimuli, have shown intriguing applications in shape-morphing and morphology control. Here, we present tunable wrinkling patterns in core-shell spheres under thermal load via controlling the orientation of director in nematic liquid crystal polymer (LCP). To analyze nonlinear instability and morphological evolution of LCP shell/core spheres, we develop a shallow core-shell model that accounts for director-induced anisotropic spontaneous strains.

Rotations with constant Curl are constant

Submitted by Amit Acharya on

Janusz Ginster        Amit Acharya

to appear Archive for Rational Mechanics and Analysis

We address a problem that extends a fundamental classical result of
continuum mechanics from the time of its inception, as well as answers a fundamental
question in the recent, modern nonlinear elastic theory of dislocations.
Interestingly, the implication of our result in the latter case is qualitatively di fferent
from its well-established analog in the linear elastic theory of dislocations.

Preprint

3D Printed Silicone Polymer : Thermo-viscoelastic experimental characterization and computational modelling

Submitted by mokarram76 on

A comprehensive thermo-mechanical experimental study and subsequent constitutive modelling will facilitate in designing and simulating more complex cellular metamaterials using 3D printed silicones

Dynamics of Electrohydraulic Soft Actuators

Submitted by Philipp Rothemund on

We have discovered two timescales that govern the dynamic behavior of electrohydraulic actuators: a viscous timescale and an inertial timescale, which depend on geometry and materials system of the actuator, and applied mechanical load and voltage. Depending on the ratio of these timescales, the actuators operate either in a viscous regime in which viscous resistance limits the actuation speed or in an inertial regime in which high speed actuation is possible.