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XFEM Crack Growth Across Bi-material Interface

Submitted by fraaztahir on
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Fracture Mechanics Forum
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xfem

 I am using XFEM in ABAQUS to simulate crack growth from one material to another. Although the crack passes through the interface, the simulation stops after crack growth of few more elements with this error:

"THE FRACTURE CRITERION f=1.5400 AT ELEMENT 2469, THE DAMAGE INITIATION TOLERANCE HAS BEEN EXCEEDED AND CUTBACK IS REQUIRED."

 This element is the one right next to the crack front.

 I have tried to increase the damage initiation tolerance > 0.5 and the crack grows one more element and then same error.

the relationship between the elastic constant of the metal and the the number of the fatigue cycles?

Submitted by Lang Zhou on
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Fatigue

Is there a relationship between the elastic constant of the metal and the the number of the fatigue cycles?If we can find the relationship of the stand test spesimen,can we use that  relationship to predict the fatigue life of other structures? 

Abaqus Modeling polymer/nanoclay (short fiber) composite model for crack propagation using XFEM

Submitted by cooljoon78 on
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Hi all,

I am working on modeling crack propagation in 2D polymer/nanoclay composite material using XFEM.

The polymer matrix would be rectangular shape and nanoclays be 2D wire.

Thus, the composite model looks like 2D rectangular and short fibers embeded in it.

The nanoclays (fibers) can be delaminated during the simulation, therefore I want to apply cohesive zone model at the interface between polymer and nanoclays.

Doctoral Studentship in high strain rate properties of Nickel Alloys

Submitted by CliveSiviour on
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impact
phd
metals
Doctoral Studentship
High Rate

The Department of Engineering Science at Oxford University has recently obtained an iCASE studentship funded by EPSRC and Rolls-Royce plc to perform research into the mechanical behaviour of metals at high temperatures and high strain rates. The studentship provides full funding (fees and stipend) at the home / EU level for 3.5 years.

Shell-to-Solid submodeling in ANSYS (APDL)

Submitted by Reza Afshar on
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Dear All

I have a question regarding Shell-to-Solid submodeling in ANSYS (APDL). I have followed the ANSYS help, but even for the same geometry used by ANYS, the stress values on the submodel are very high and at the wrong position.

I was wondering if any one has a tutorial on Shell-to-Solid submodeling in ANSYS (APDL) or any hints regading this type of submodeling?

Thank you in advance

Reza 

Weakness

Submitted by mohammedlamine on
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Tetrahedron volume weakness

Hi all,

There are several formulae allowing the computation of tetrahedral volume elements. The weakness of some of them is that they give negative volumes. This is due to the vector dot product and its direction. You must take care when using them.

You have to check your formula with some simple examples like the vertices of the following one: (1,0,0) , (0,1,0) , (0,0,1) , (0,0,0). 

 

Mohammed lamine Moussaoui 

Pull out in fabric

Submitted by jagan on
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kevlar
pull out

Dear all,

 I have been trying to model pull of single yarn in abaqus and model is responding. i got a problem now. I am applying velocity in one of the yarn and I am pulling it out.Boundary conditions are fixed on both the sides. to calculate the force that is being applied on to the fabric, pull out force, I summed up all the reaction quantites RF1,RF2,RF3 and i plotted it against displacement. but the force is touching zero sometimes. i dont know the reason. what could it be?

 P.S. : I have attached my pull out graph also.

 

regards

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