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Plane stress Abaqus UMAT

Submitted by lefteris tsivolas on
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Hello everyone,

I have created a UMAT code for J2 elasto-plasticity with isotropic hardening for 3D solid elements.

At this point I would like to support also plane stress shell elements. What changes in the code are

suggested? The already implemented code, takes as input the strain tensor at time tn and the strain

increment tensor and updates the stress at time tn+1 and calculates the material Jacobian and 

achieve quadratic convergence. The stress and strain tensors are manipulated as 6x1 vectors and the 

Novel Metamaterials based on Triply Periodic Minimal Surfaces

Submitted by Rashid K. Abu Al-Rub on

Recently, there has been a growing interest in investigating the multi-functional properties of novel types of metamaterials, metastructures, and metacomposites based on triply periodic minimal surfaces (TPMS). TPMS have been discovered more than 160 years ago and thanks to additive manufacturing (3D printing) they become reality only recently and opend the doors for several applications.

Structures loaded with a force acting along a fixed straight line, or the “Reut’s column problem”

Submitted by Davide Bigoni on

How to provide a structure with a force lying on a fixed line?
We provide the answer to this question in our paper: Bigoni and Misseroni (2019) Structures loaded with a force acting along a fixed straight line, or the “Reut’s column problem”.
Journal of the Mechanics and Physics of Solids.
Enjoy watching our video below (would you have trouble playing video on YouTube, click here to watch it).

Configurational forces and nonlinear structural dynamics

Submitted by Davide Bigoni on

How a mass falls when attached to a flexible element with varying length?
We provide the answer to this question in our paper: Armanini, Dal Corso, Misseroni, Bigoni (2019) Configurational forces and nonlinear structural dynamics.
Journal of the Mechanics and Physics of Solids.
Enjoy watching our video below (would you have trouble playing video on YouTube, click here to watch it).

The Elastica Catastrophe Machine

Submitted by Francesco Dal Corso on

May a catastrophe machine be realized through an elastic continuous element?
We provide a positive answer to this question in our paper: Cazzolli, Misseroni, Dal Corso. Elastica catastrophe machine: theory, design and experiments. Journal of the Mechanics and Physics of Solids.

Enjoy watching our videos below (would you have trouble playing videos on YouTube, click here to watch them).

 

Functionalized helical CNT fibre bundles as biosensors for healthcare

Submitted by Fan Xu on

Mechanical mismatches between implanted electronics and biological tissues can lead to inaccurate readings and long-term tissue damage. Here, we show that functionalized multi-walled carbon nanotubes twisted into helical fibre bundles that mimic the hierarchical structure of muscle can monitor multiple disease biomarkers in vivo. The flexible fibre bundles are injectable, have a low bending stiffness and display ultralow stress under compression.

Prediction of forming limit diagrams using machine learning

Submitted by vh on

Measuring forming limit diagrams (FLDs) is a time consuming and expensive process. Machine learning (ML) methods are a promising route to predict FLD of aluminium alloys. In the present work, we developed a machine learning (ML) based tool to establish the relationships between alloy composition / thermomechanical processing route to the material's FLD.

Mode II fracture of an elastic-plastic sandwich layer

Submitted by Emilio Martíne… on

Dear iMechanicians,

Please find below a paper, co-authored with Ivan Cuesta and Norman Fleck, on the mode II fracture of elastic-plastic sandwich layers. The paper is part of the special issue in the Journal of Applied Mechanics dedicated to John Hutchinson's 80th anniversary and the Century Fracture Mechanics Summit.

Soft Magneto-Active Composites

Submitted by Stephan Rudykh on

"Soft magnetoactive laminates: large deformations, transverse elastic waves and band gaps tunability by a magnetic field"  by  N. Karami Mohammadi et al (2019) has been published in November Special Issue in Journal of Applied Mechanics.

This paper is part of my group and co-author work on the topic of Soft Magneto-Active Composites:

Harnessing energy landscape exploration to control the buckling of cylindrical shells

Submitted by Teng zhang on

Abstract: Even for relatively simple thin shell morphologies, many different buckled configurations can be stable simultaneously. Which state is observed in practice is highly sensitive to both environmental perturbations and shell imperfections. The complexity and unpredictability of postbuckling responses has therefore raised great challenges to emerging technologies exploiting buckling transitions.