Dear All,
I am modelling a 3 point bend specimen with Cohesive elements tied to the upper and lower halves of the specimen in 2d.
The problem is that the CZ elements perform properly only for a combination of element sizes, i.e. a combination of element size of structure and CZ elements, for instance in my case the structure/specimen element size is 0.2mm and CZ is 0.001 or 0.002. For any other combination the adjacent elements bend as shown in the attached image.
I will be glad if someone could explain this behaviour and the solution.
I also attach the input file.
I am not sure about the node numbering issue of Cohesive elements. I meshed the elements assigning sweep path along normal to the crack propagation direction.
With regards,
Abhishek
| Attachment | Size |
|---|---|
 CZbend.jpg | 391.23 KB |
 ML4CZ1.pdf | 15.07 MB |
Hello, All
***Problem ***
Failure pressure for Steam generator tube having 2 axial cracks. I am following one paper in that paper they found failure pressure by finding J and K values for line spring elements for different pressure. The pressure at which it approach material JIC(92N/mm) and KIC(65Mpa*sqrt(m)) value is considered as failure pressure or coalescence pressus
**Modelling**
I modeled steam generator tube having diameter of 22mm and thickness of 1.27 mm. It has 2 axial cracks of 6.35mm and lengths between cracks is 0.254mm. Length of the tube is 220mm, so I can assume it as a infinite cylinder.I modeled quarter symmetry of tube. I modified input file to create crack as a line spring elements, 31 line spring elements are created on crack. The tube has S8R shell elements.
**Material Property**
Material is Alloy 600.
Material property (Entered in ABAQUS): Elastic Modulus : 200 Gpa, Poission ratio : 0.3
Plastic property : Stress(MPa)Strain(mm/mm)
300 0
512 0.09274
687 0.178865
840 0.2582
946 0.33177
1125 0.5
1700 1.05
**Questions**
When I ran the analysis for 33Mpa my J reached value of 95 N/mm.And it shows 2 warnings.
1>The line spring elasticity predicts closing of the flaw at 2 points
2>The line spring plasticity theory is intended for tensile and opening moment loading of a flaw. 2 points have elastic stress states which violate this condition
Thank you for comment and advice on my post (crack using line spring elements)
I have one node that is showing stress singularity and it did't show up in warning when I monitor result. However when I went into job diagnostic it shows that one node has stress singularity I found that node and the node has boundary condition of Y symmetry. I am attaching image where node is located at. When i fixed that node it don't show any warnings in Job diagnostic but fixing the node is not realistic I think as I am using quarter symmetry.
if you have any another advice why this is happening or what else I can do to remove this warning I would really appreciate your help.
Thank you again.
Can anybody help me in using smeared crack and cohesive zone modeling in concrete for different grades. I was actually facing problem in using the same to identify fracture parameters of concrete using ABAQUS. I will also be helpful if anyone let me know about an alternate method to find fracture parameters of concrete using ABAQUS apart from using models. Thanks in advance.......
Hello,
I am currently working on fracture toughness of aluminium 2014. At the first stage an experiment of fracture toughness was carried out in order to identify the experimental results. The I model the specimen in Abaqus in order to compare experimental and FEA results. My question is how can i know what load i will use for the model? From experimental results I have that the maximum load was used for the specimen was 2kN. Am I going to use this value for load? Also the specimen is aluminium alloy 2014. I entered some material properties such as young modulus and poisson`s ratio. Are they enough or need to enter more material properties in order to get accurate results?
Kind Regards