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Neo-Hookean

Deriving a lattice model for neo-Hookean solids from finite element methods

Submitted by Teng zhang on

Lattice models are popular methods for simulating deformation of solids by discretizing continuum structures into spring networks. Despite the simplicity and efficiency, most lattice models only rigorously converge to continuum models for lattices with regular shapes. Here, we derive a lattice model for neo-Hookean solids directly from finite element methods (FEM). The proposed lattice model can handle complicated geometries and tune the material compressibility without significantly increasing the complexity of the model.

Tangent modulus of the Mooney-Rivlin based Neo-hookean - Could you check my derivation??

Submitted by Hobeom Kim on
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Hello.

 

I study solid mechanics at a graduate school.

 

I tried to derive tangent modulus of the Mooney-Rivlin based Neo-Hookean material.

 

There might be no error in my derivation, but answer is wrong with referred right answer.

 

So, could you check my derivation?

 

I attached my derivation as a figure.

Tangent modulus of the Mooney-Rivlin based Neo-hookean - Could you check my derivation??

Submitted by Hobeom Kim on

Hello.

 

I study solid mechanics at a graduate school.

 

I tried to derive tangent modulus of the Mooney-Rivlin based Neo-Hookean material.

 

There might be no error in my derivation, but answer is wrong with referred right answer.

 

So, could you check my derivation?

 

I attached my derivation as a figure.

 

 

 

Thanks in advance.

plane stress incompressible neo-Hookean hyperelasticity

Submitted by SAMICORP on

Hello, 

I was wondering how is it possible to implement incompressible neohookean material in abaqus? 

With the incompressibility assumption c(3,3)=1/(- c(1,2)^2 + c11*c22), with c being the Cauchy-Green strain tensor. It also implies that S33=0 and it is possible to find the pressure directly. In addition, h=sqrt(c(3,3))*h0 with h and h0 being current and initial thickness, respectively. 

my question is that how is it possible to implement the last condition in umat? 

 

 

 

 

 

Linear Elastic material behaves as Neo-Hookean in ANSYS?

Submitted by Breslavsky on

I solve the static bending problem for thin plate under uniformly distributed load acting orthogonally to the plate. I

need the solution up to quite large values of deflection (100

thicknesses, which implies the strains about 100%), but I want to take

into account only geometric nonlinearity and not the material

nonlinearity. I use elements which support large strains (SHELL181,

SHELL281). The software is ANSYS Mechanical APDL 12 and 13. Also, I use "Large displacement static" option for

solution.

Writing User Subroutines with ABAQUS

Submitted by Ahmad Rafsanjani on

Dear All,

 I think that many students are looking for some tutorials about writing a UMAT in ABAQUS.

You can find a comprehensive tutorial for elastic problems.

This file contains: 

• Motivation

• Steps Required in Writing a UMAT or VUMAT

• UMAT Interface

Examples

Example 1: UMAT for Isotropic Isothermal Elasticity

Example 2: UMAT for Non-Isothermal Elasticity

Example 3: UMAT for Neo-Hookean Hyperelasticity