Strange Spike Element

[sbasude]

Hello,

I am having trouble figuring out why one of my elements is acting strangely. I am working with a heterogeneous bone model simulating a compression test. After about a third of the step, one of the elements begins spiking out. The element is located far from the analytical rigid I am using to push on the bone (see the drawn red arch) or the constrained end. Any insight is greatly appreciated.

 

[FEA way]

Check mesh quality in the Mesh module (Verify Mesh tool). This element may have poor quality parameters. Try refining mesh in this area. Also examine warnings and sets generated automatically by Abaqus. Some include severily distorted elements.

If this mesh was generated outside of Abaqus and then imported as orphan mesh, there might be an error in the import procedure. Or maybe it was generated with error already since the geometry is probably from scan.

 

[sbasude]

Hi FEA way,

Yes I definitely have many distorted elements... no matter how clean I try to mesh this that has never changed. But I have never seen a spike like this. Could it be something different or because this is a bit coarser?

 

[FEA way]

Indeed there are always some distorted elements but thanks to quality parameters (such as aspect ratio) you can find the worst element/elements. Such single element distortion may also happen when you apply some sort of wrong constraint. For example tie constraint with too high adjustment tolerance may result in excessive distortion of an element when it tries to merge it with neighboring node.

Check all your sets used for definitions of BCs, loads, sections etc. Maybe this element was mistakenly selected (or deselected) in some set.