moustachiio's blog
https://imechanica.org/blog/26528
enenergy balance of surface-based cohesive of composite under impact in Absqus 6-10
https://imechanica.org/node/10508
<div class="field field-name-taxonomy-vocabulary-6 field-type-taxonomy-term-reference field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/128">education</a></div></div></div><div class="field field-name-taxonomy-vocabulary-8 field-type-taxonomy-term-reference field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/taxonomy/term/289">ABAQUS</a></div><div class="field-item odd"><a href="/taxonomy/term/569">composite materials</a></div><div class="field-item even"><a href="/taxonomy/term/610">damage in composites</a></div><div class="field-item odd"><a href="/taxonomy/term/1213">Interface debonding; Size effect; Homogenization; Particulate composites; Constitutive equation</a></div><div class="field-item even"><a href="/taxonomy/term/4877">composite delamination</a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>
Hi there! I am really new to Abaqus and I need to model a composite<br />
laminated crash cone under impact to a flat solid wall (analytical<br />
surface is used). I modelled a cone with a layers of conventional shell<br />
elements with hashin failure criteria and surface-based cohesive<br />
behaviour as interaction between layers representing the interface of<br />
composite laminates. The model runs successfully but once I checked the<br />
energy balance, the damage dissipation energy from the cohesive, it<br />
turned out to be NEGATIVE (I think this is wrong).<br />
I tried to model a simple geometry model with cohesive elements and the<br />
damage energy from cohesive element is POSITIVE (which seems to be<br />
correct).
</p>
<p>
As far as I know the energy balance: internal energy =<br />
strain energy + artificial energy + damage dissipation energy + penalty<br />
contact energy +contraint penalty energy + plastic energy
</p>
<p>
where Total energy = internal energy + viscous energy + kinetic energy + frictional energy + external work = constant<br />
I set up another history field output request to capture the energy of<br />
hashin damage to compare with the all damage energy of model and the<br />
result is that damage from surface-based cohesive is NEGATIVE. This<br />
means the more damage to the cohesive, the less internal energy in the<br />
cone which means that less energy absorbed from the impact. <--<br />
totally wrong...
</p>
<p>
Due to the complex geometry of the model, cohesive element does not seem to the one I can apply to my model.<br />
Could anyone explain or give me a solution why the damage energy from surface-based cohesive is NEGATIVE? Is it wrong?
</p>
<p>
Here is the interaction property of the surface-based cohesive
</p>
<p>
** INTERACTION PROPERTIES<br />
** <br />
*Surface Interaction, name="interface prop"<br />
*Cohesive Behavior, eligibility=ORIGINAL CONTACTS<br />
20000.,15000.,15000.<br />
*Damage Initiation, criterion=QUADS<br />
60.,90.,90.<br />
*Damage Evolution, type=ENERGY, softening=EXPONENTIAL, mixed mode behavior=POWER LAW, power=2.<br />
0.6,2.,2.<br />
*Contact Damping, definition=CRITICAL DAMPING FRACTION<br />
0.1,
</p>
<p></p>
</div></div></div>Sun, 03 Jul 2011 21:58:49 +0000moustachiio10508 at https://imechanica.orghttps://imechanica.org/node/10508#commentshttps://imechanica.org/crss/node/10508Error | iMechanica