Hi,
I am trying to understand Abaqus Benchmark example 1.19.2 - Crack proagation in a plate with a hole simulated using XFEM.
I ran the python script provided "crackprop_hole_lefm_xfem_cpe4.py" from the site: http://dsk.ippt.pan.pl/docs/abaqus/v6.13/books/bmk/default.htm?startat=…
I want to try and output figure 1.19.2 - 4.
Hi
I need to build a model to predict the fatigue life of notched metal. No pre-existing fatigue crack, as the specimens is not based on the ASTM standards.
The crack initiation from a notch, and then propagation till failure needed to be accounted for.
The plasticity at the notch due to the cyclic loading & the crack closure effect needed to be considered.
I wonder if anyone in Imechanica follows or deals with Damage Tolerance of Aircraft Structures. Not having to deal with everyday certification nor having direct experience, I know only what is reported in academic books, but I am confused about what is the standard in industry and certification, assuming there is one!
SUMMARIES OF AIRCRAFT LIFING CONCEPTS
Safe-Life design
G'day all
Having a metal element with a notch like crack (assume sharp one, exhibits plasticity), what are the actual fracture mechanism (the phases the crack goes through) in the total fatigue-life.
please comment on these scenarios:
1- crack initiation life calculated from the (S-N, e-N), then using LEFM/EPFM to determine the cycles for the crack propagation to failure...
Q/ how to find the crack length between the two phases, I mean from which stresses and at which crack length we start the crack propagation life estimation.
Hi All
The fracture mechanics of multiaxial fatigue loading In steel plates have been studied comprehensively since the late 70s.
simplified the case with an inclined crack in uniaxial load has been investigated in metal by many researchers, as well.
in this forum, few researchers present their work that focuses on crack initiation from notched in metals.
So what I am studying is a combination of the all component above together, Yes the notch exhibits plasticity, under the load applied.
Hi
I want to check the stress biaxiality at critical location in FE model. the load applied is proportional cyclic but the at stress concentrator lacation and due to the complex load states (multi-axial) I am not sure if the stresses proportional or not as that will effect the critrerion suits this case.
Is the check to be for the principle stress ratio (S2/S1) only.
should the check be conducted on one line of nodes (along the maximum stress location), or all node/or element in the area surround the stress concentrator.
I have written vumat codes of a cohesive model of Needleman (whose paper entilted "Numerical simulations of fast crack growth in brittle solids"), and I have implemented it into ABAQUS/Explicit, but the predicted result is wrong. I don't know why. The corresponding fortran file is as follows:
subroutine vumat(
C Read only (unmodifiable)variables -
1 nblock, ndir, nshr, nstatev, nfieldv, nprops, lanneal,
2 stepTime, totalTime, dt, cmname, coordMp, charLength,
Hi All
the stress intensity factor SIF of crack in the fIG. A attached has two components: for tension and shear
the SIF formula of this specimens derived in the literature and tabulated for different angles and crack length.
Is there a way to define the SIF of this specimen in term that one of crack perpendicular on the load (straight horizontal crack) in Fig. B
your comments will be helpful
I did evaluation of J-integral distribution along a 3D semi-elliptical internal surface crack in a thick-walled pressure vessel using ANSYS APDL. The results I got included positive and negative values. Sometimes the values were all positive or negative and in other cases, negative and positive values were combined. What could be the interpretation of negative and positive values in ANSYS. I seriously seek assistance from someone.
Hello everybody,
I am doing such a kind of FE simulation using ABAQUS Explicit for composite delamination analysis. In this case, I have used once Cohesive Zone Element (CZM) and then with Cohesive Surface for deboning analysis
The simulation is itself quite dynamic process, somehow the deformation time is only around 3[ms] and the deformation speed is around 5[m/s].
I used the same characteristics for both CZM and Cohesive Surface description. Enhanced Hourglass was also used for Element Control.
The problem is as below:
