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Bone remodeling: Komarova model

Dear Community,

I make a code public for bone remodeling, using the Komarova model. It was developed by me alone. I provide the code as is, without warranty.

The agreement between my data and the ones from a reference are very good for fixed loading, but deviate for a more intricate loading. Lacking access to Abaqus with a Fortran compiler, I am at present unable to pinpoint the cause for the discrepancy between my data and data from the reference. The code can serve as a starting point and I give directions how to identify the cause for that discrepancy.

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reflection and transmission coefficients in long elastic bars

 

Dear iMechanica Community,

I'd like to ask for advice on modelling reflection and transmission coefficients when two bars with different cross-sectional areas contact each other and are exposed to pulse loading.

I have modelled this process in Abaqus/Explicit as a two-dimensional simulation. The investigation was conveniently done as a parametric study, defining the lateral dimension as parameter. Both bars are slim (length 2 m, diameter 2 cm) and elastic.

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UMAT for Zener model and Kelvin-Voigt model

Dear iMechanica community,

you can find the UMAT-implementation of a Zener model, i.e. a Maxwell model parallel to a spring, in my PhD thesis:

“Upsetting and Viscoelasticity of Vitreous SiO2: Experiments, Interpretation and Simulation“
Technische Universitaet Berlin, Germany, 2006
https://depositonce.tu-berlin.de/handle/11303/1574
http://dx.doi.org/10.14279/depositonce-1277

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Subroutine DFLUX in ABAQUS

Dear Mechanicians,

time and again the question of modeling moving heat sources pops up, often in the context of laser heating.

One can achieve this using the subroutine DFLUX in ABAQUS.

I decided to post some links here to avoid responding with a longer explanation to every individual seeking assistance.

Please note that I have never worked with any one of these codes and have no access to ABAQUS at present.

No warranty is given by me.

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ABAQUS built-in SMA model

Dear Mechanicians,

time and again the question of SMA (shape memory alloy) modeling pops up.

In ABAQUS, you can achieve this only by (V)UMAT coding or by using the little-known built-in SMA model.

In the past I have frequently responded to queries on SMA modeling and could refer to a customer help site of SIMULIA. That site is down, regrettably.

I decided to post the files here to avoid responding with a longer explanation to every individual seeking assistance and uploading the files as E-mail attachment every time.

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uniaxial compression of metals: data compilation

 

Dear Group,

I am looking for a compilation of data of the uniaxial compression test of metals at high temperature.

This type of test is commonly used to extract parameters for the equation
strain rate = function of stress (peak stress or steady state flow stress) and temperature
among them the activation energy for flow

I'd need, independently:

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Uniaxial compression of heterogeneous/cellular material (bone)

 

Dear colleagues,

I kindly ask for advice on the following problem:

I simulate the uniaxial compression of a heterogeneous cylinder representing bone. Thus, it is not the visible solid exterior rim of the bone, but represents a porous structure within the bone, so-called trabecular bone, see the figure underneath.

The simulation is done in ABAQUS. The sample contains 164175 elements of type C3D4. The heterogeneous, porous structure makes it impossible to use axisymmmetric elements. The constitutive behavior is ELASTIC.

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Inverse problem in beam bending, elastic-ideally plastic material

Dear iMechanica,

suppose you have a beam with a square cross-section, manufactured from an elastic-ideally plastic material.

Now apply a load that rises linearly in time, but is locally constant along the beam length. Upon sagging, the beam will develop a plastic zone beginning in the top and surface regions at mid-length.
This is the "straight" problem solved in Prager, Hodge: Theory of perfectly plastic solids, publisher: Springer

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Section points in user elements

 

Dear Group,

does anyone know how section points can be defined in user-defined elements UEL ?

I am trying to program my own beam element in ABAQUS. The beam element library does not provide a beam element with temperature as a degree of freedom which would come as an asset in our application.

Beam elements feature so-called section that provide the spatial resolution through the thickness. I cannot find any clue how this can be programmed. ABAQUS standard elements give results for strain, stress and the like at these section points.

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