Low velocity impact

[vikram manoj]

i am performing a low velocity impact on a 32 layer [0/90] orientation of fiber . As we know the fiber tension failure starts form the bottom layers, but in my case the fiber tension damage starts at the top layers. what may be the reason. Please help me in this regard.

 

[FEA way]

Are you talking about a simulation or a phyiscal test ? Can you share some screenshots showing your results and possibly the analysis/test setup ?

 

[SWComposites]

and what are you using for material properties?
one possible reason may be the local contact stresses at the impact surface are very high due to model assumptions.
are you using a rigid impactor?
how is the composite plate supported?

 

[vikram manoj]

i am using carbon epoxy (T300/YH69) properties. I am attaching the material properties image, and yes i am using rigid impactor. I am considering a half plate which is subjected to multiple impact at some distances form the center of the plate, and on one side i am applying a Y-symmetry boundary condition and two sides fixed boundary conditions. i am performing simulation in Abaqus. I am using general contact explicit algorithm between layers and impactor.

 

[vikram manoj]

Simulation file

 

[Compositepro]

It is common to get delamiation in the middle of the thickness of the panel followed by compression failure of the top surface under the impactor. The delamination significantly reduces the bending stiffness of the panel.

 

[SWComposites]

i suspect the issue may be the rigid impactor.
please show deflection plots of the panel at various time steps after contact starts
and what failure criteria are you using to predict ply failure? and to predict onset and growth of delaminations?

 

[GregLocock]

In a shear (punching) failure you'd expect he top fibres to break first, whereas with a bending failure the bottom layers will fail in tension.

Cheers

Greg Locock


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