Abaqus Plastic Deformation

Tutorial 5: Simple plastic deformation with unloading Laurence Marks

Strategic Simulation & Analysis Ltd Southill Barn, Southill Business Park, Cornbury Park, Charlbury, Charlbury, Oxfordshire, OX7 3EW T. 01608 811777 F. 016088117 01608811770 70 [email protected] W. www www.ssanalysis.co.uk .ssanalysis.co.uk

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Geometry Import

Import the geometry in the form of a step file – Tutorial 5.stp

Strategic Simulation & Analysis Ltd Southill Barn, Southill Business Park, Cornbury Park, Charlbury, Oxfordshire, OX7 3EW T. 01608 811777 F. 01608811770 [email protected] W. www.ssanalysis.co.uk

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2.

Material and section properties

Start to define the material properties – go into the properties module Define a linear steel property – this is used for the supports and load application part. No point in allowing that to yield. Name this material ‘Steel_Linear’.


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Now define a new steel material with plastic properties – define the elastic properties as before but now include a second plastic behaviour and include yield and strain properties. Name this ‘Steel_NonLinear’

Now create two sections – one called Steel_linear and one called Steel_NonLinear


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Assign the section to the relevant parts – the bar should be non-linear and the other parts linear.

Go into the assembly module to instance the parts.


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3.

Define the first analysis step

Create a static general step and include Nlgeom and automatic stabilisation.

Set an initial time increment of 0.01 and a maximum of 0.05


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4.

We now define the contacts

Create an interaction property with a friction coefficient of 0.1. Next create a surface to surface interaction.

Contacts are defined by individually selecting faces for the master and slave surfaces as shown below.

Repeat the process for the lower face of the bar.


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5.

Define Loads and Restraints

In the boundary conditions option we create a Displacement/Rotation on the faces highlighted below. Now apply a displacement of 0mm in the axis perpendicular to the faces selected. This will restrain t he model allow only sliding movement and therefore will act as a symmetry plane.

Repeat this process to create a symmetry restraint on the other surface.


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Now fully fix the support in all 3 directions.

Since we know the distance which we want to load application part to travel we shall apply a displacement to its top face. This becomes particularly useful when trying to determine the force required to assemble two latching parts or the force required to cause a certain amount of deflection or travel on a component. Apply a 35mm displacement to the top face of the central part in the vertical direction. This will be applied as a linear increment as the analysis progresses.


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6.

Meshing

The assembly was instanced as dependant and therefore the model needs to be meshed by part. Seed the beam with 2mm hex elements and the remaining parts 3mm hex. Mesh each part. The model should now look like this...

It is assumed that anyone working through this tutorial will already be famili ar with the meshing approached adopted by Abaqus CAE. If this isn’t the case then work through tutorials 1 and 2. In this model there is no need to change the meshing approach from the default hex option. Mesh seeding button Meshing button


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7.

Create and Submit a Job

Remember to name the job something relevant to the model.

Whilst the solution is running monitor its progress


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8.

View the Results

Plot the displacement and check whether the central component has displaced by 35mm as specified.


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9.

Add the unloading step and re-submit

We can add another analysis step and use the same settings as in the first step. We can use this to define the unloading phase of the simulation. Create a new step after Step-1. Remember to include Nlgeom and automatic stabilisation and define the time increments - Initial: 0.01, Max: 0.05. All the other loads/restraints/interactions etc. are propagated from the previous step. To unload the component we need to modify the displacement that loaded the model in Step-1. Open the boundary condition and modify the 35mm displacement to 0mm.

Re-run the solution by re-submitting the job.


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Once the analysis has completed we can animate the model to see the unloading step take place.

The plot here shows the model reflected in two symmetry planes. This is done by selecting mirror planes in the odb display options dialog box.

Define mirror planes here


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Abaqus Plastic Deformation

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