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How to use non-dimensional form in open source codes instead of Units

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I am using an open source FEM platform, which requires you to convert your equation system to non-dimensional form. So, there are no units specified for the parameters in the problem. If you use compatible input units, you should expect the output in matching unit - just like one would do in a normal python or C++ code for solving physical problems. I have an elasto-plastic dynamic problem to solve, and these are the parameters for the Drucker-Prager Soil Model for soft clay.

E = 5000000;                 // Young's Modulus in N/m^2 or Pa

Problem between diaphragm and embeded region in ABAQUS

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Hello every one,

I am modeling a core (C shape) subjected to lateral load. I used embeded region constraint to contact steel bars and stirrups to the solid core. Then i want to apply the load at one end of core, but i need to contact all points in this end with a diaphragm to take the effect of the slab which aren't modeled. But i thing that ABAQUS doesn't permit to use two constraints at the same point. So what can i do to constrain the steel bars to core and also to constrain all points at one end with a diaphragm.

Thanks in advance

Rectangular frame calculation by beam finite elements

Beam elements are very widely used in structural engineering. Here we consider the methodology for calculating the rectangular frames with articulated or rigid nodes. The load is evenly distributed and concentrated.  The result is exactly the same with the results of the method of force and displacement method. A practical example of the calculation of the frame.

Henry Tan's picture

Journal Club for October 2016: Roughness evolution of biomaterial surfaces

As an example, here we discuss implant-associated infection from the mechanics point of view on bacteria adhesion affected by the biomaterial surface roughness:

1.    Implant-associated infection, a leading cause of failure in many biomedical devices, is caused by adhesion of bacteria to the surface of biomaterials. Implant-associated infection is difficult to treat, for example, joint replacement infections may occur deep around the artificial implants.

Elastic-plastic analysis by 4 nodes isoparametric finite element. Theory Mises

 The relationship between the strains and stresses will be considered based on the premise that for every increment of load deformation occurs, consisting of two parts - the elastic and plastic

Lazuardi Pujilaksono's picture

Fatigue crack propagation

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Hi, I'm trying to perform a supposedly-simple experiment on fatigue crack propagation of UHMWPE. I use a compact-tension specimen on a servopulser hidraulic testing machine. I will try to do the experiment on a fix Pmax with a varied force ratio (R) from 0.1 to 0.5. I'm having trouble in deciding the maximum force Pmax. How does one decide the amount of force applied for FCP testing? Calculation steps and so on.

Siva P V Nadimpalli's picture

Time-dependent deformation behavior of polyvinylidene fluoride binder: Implications on the mechanics of composite electrodes

Time-dependent deformation behavior of polyvinylidene fluoride binder: Implications on the mechanics of composite electrodes (http://www.sciencedirect.com/science/article/pii/S0378775316312721)

Arnuparp Santimetaneedol, Rajasekhar Tripuraneni, Shawn A. Chester, Siva P.V. Nadimpalli 

Arash_Yavari's picture

Compatible-Strain Mixed Finite Element Methods for 2D Compressible Nonlinear Elasticity

In this paper, using the Hilbert complexes of nonlinear elasticity, the approximation theory for Hilbert complexes, and the finite element exterior calculus, we introduce a new class of mixed finite element methods for 2D nonlinear elasticity -- compatible-strain mixed finite element methods (CSFEM). We consider a Hu-Washizu-type mixed formulation and choose the displacement, the displacement gradient, and the first Piola-Kirchhoff stress tensor as independent unknowns. We use the underlying spaces of the Hilbert complexes as the solution and test spaces.

How to know the element number within an hetval subroutine

Hi everybody

I'm a new user of abaqus and I'm trying to describe the heat generation in a changing phase thermoset polymer using abaqus user subroutine HETVAL. I need for my computations the current element number (in such a way that I can find the adjacent elements in the connectivity matrix).

Does anyone have any suggestion?

Thank you

Amir Nasirmanesh's picture

Eigenvalue buckling analysis of cracked functionally graded cylindrical shells in the framework of the extended finite element method

Hi everybody

My new paper on the buckling behavior of cracked FGM shells has been published in the Composite Structures.

I would be very happy to answer any further question.

I attached the pdf file of the paper to this blog.

kshitij_gaikar's picture

Simulation of moving wheel on the rail?

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Hi Guys,

mohamedlamine's picture

Publication

Hi all,

I am pleased to post the references of my recent paper entitled :

"CONTRIBUTION TO BRIDGE DAMAGE ANALYSIS" Mohammed Lamine MOUSSAOUI, Abderrahmane KIBBOUA, Mohamed CHABAAT

APPLIED MECHANICS AND MATERIALS Journal,

Volume 704 (2015) pp 435-441

DOI: 10.4028/www.scientific.net/AMM.704.435

 

N.B: The equation (7) has been reviewed with:

[P2](nxg)=[[I](nxn)| [0](nxf)]

and is available at:

Does internal heat transfer attribute work with VUMAT subroutine?

I am running J-C plasticity VUMAT subroutine and trying to club inbuilt heat transfer attributes for temperature update, but it's not working. I would appreciate if someone can advise me if there any way to club inbuilt heat transfer with VUMAT or I have to write separate subroutine? 

Thanks & Regards,

Abhishek

Jinxiong Zhou's picture

Soft mobile robots driven by foldable dielectric elastomer actuators

A cantilever beam with elastic hinge pulled antagonistically by two dielectric elastomer (DE) membranes in tension forms a foldable actuator if one DE membrane is subject to a voltage and releases part of tension. Simply placing parallel rigid bars on the prestressed DE membranes results in enhanced actuators working in pure shear state. We report design, analysis, fabrication and experiment of soft mobile robots that are moved by such foldable DE actuators.

Post-Doc position within the International Research Training Group "Integrated Engineering of continuous-discontinuous long fiber reinforced polymer structures” (DFG GRK 2078)

The international research training group "Integrated Engineering of continuous-discontinuous long fiber reinforced polymer structures” offers one post-doc position at Karlsruhe Institute of Technology (KIT). Discontinuous long fiber reinforced polymer structures with local continuous fiber reinforcements represent an important class of lightweight materials. This class of materials has a significant potential for energy savings due to the high specific stiffness and strength as well as the variety of design options in diverse technical applications, e.g., in vehicle construction.

Payam Soltani's picture

Tuning of a piezoelectric vibration absorber attached to a damped structure

Tuning of a piezoelectric vibration absorber attached to a damped structure

By : Payam Soltani, Gaetan Kerschen, Gilles Tondreau, Arnaud Deraemaeker

Abstract:

tarkes's picture

Defining perioidc BC for 1 element elastic model for Biaxial pull in ABAQUS

For simplicity in understanding Perioidic BC in ABAQUS, I am trying to implement in a single element elastic model.

Material is elastic. There are two reference points defined Refpoint 1 for x-direction pull and Refpoint 2 for y-direction pull. Please find the attached picture for clarity in the model.

 

I have defined the equations for PBC in ABAQUS as below:

 

x1-x2+Refpoint1=0

y1-y2+Refpoint1=0

 

x3-x4+Refpoint1=0

y3-y4+Refpoint1=0

 

x2-x3+Refpoint2=0

y2-y3+Refpoint2=0

 

Congrui Jin's picture

Elastic Microplane Formulation for Transversely Isotropic Materials

Our recent work investigates the extension of the microplane formulation to the description of transversely isotropic materials such as shale rock, foams, unidirectional composites, and ceramics. Two possible approaches are considered: 1) the spectral decomposition of the stiffness tensor to define the microplane constitutive laws in terms of energetically orthogonal eigenstrains and eigenstresses; and 2) the definition of orientation-dependent microplane elastic moduli.

Microstructure modeling of random composites with cylindrical inclusions having high volume fraction and broad aspect ratio distribution

We proposed a computational methodology for generating microstructure models of random composites with cylindrical or sphero-cylindrical inclusions having high volume fraction and broad aspect ratio distribution. The proposed methodology couples the random sequential adsorption (RSA) algorithm and dynamic finite element (FE) simulations. It uses RSA to generate sparse inclusion assemblies of low volume fraction and subsequently utilizes dynamic FE simulation for inclusion packing to achieve high volume fractions.

shreeram111's picture

Crack tip mesh size - Interface cracks ?

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Hello everybody,

                   I am working on FE Simulation of interface cracks. To this end, I use modified VCCT, CSDEM and other such methods to determine mesh independent strain energy release rate (G) and Mode mixity (ψ). Now I have a fundamental doubt.

Kmomeni's picture

Special issue on "Low-Dimensional Phase Transforming Materials"

A special issue of Journal of Nanomaterials is devoted to "Low-Dimensional Phase Transforming Materials" which obtained significant interests in the recent years. This topic covers a broad range of research such as 

Implicit vs explicit result in damage-mechanics+plasticity model

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Hello experts, I am trying to model the response (damage+plasticity) and compare with commercial FE codes. I chose to follow explicit scheme and compare with available implicit solution. Attached image shows the comparison between implicit (commerical FE software) and explicit (my Python program).

 As it can be observed, near the failure, i.e. applied strain > 0.05, there is a noise in the explicit solution. When I decrease the time step, the noise infact decreases.

(a) Is this noise is a result of explicit procedure ? or some thing wrong with my algorithm ?

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