Week 5 Sphere pressing on a plate

SPHERE PRESSING OVER A PLATE ANALYSIS

OBJECTIVE

To perform a sphere pressing over a flat plate simulation using Ansys where the flat plate is modeled as a non-linear structural steel material and the sphere is displaced against the plate ot a max of 4mm normal to the plate. The equivalent stress and strain data along with the directional deformation observed in the plate are extracted and plotted.

PROCEDURE

• Create a new static structural simulation
• Import the structural steel NL onto the engineering data since plasticity will be expected for the following simulation. The srtess strain plot in the plastic region fot the following material is shown below

• Import the geometry file onto the Spaceclaim GUI. Since this is a symmetrical component, the model is split to 1/4 of the entire part to reduce computational intensity.

• Then the model module of static structural is again updated.
• Open the model in ansys mechanical module.

Material assignment

• Structural steel NL is added to the plate and structural steel for the sphere

Contact region

• A single contact set is defined between the two comp with a frictional contact of 0.75 (since steel and steel contact) coeff of friction

Mesh

• The default mesh is used however to refine the mesh we can either increase the mesh density using sizing option or alternatively we can create a well structured ortho tria mesh on the speciment using face meshing feature

Symmetry

• Two symmetrical definition is created for both the sides of the sphere, with the symmetrical normals being Z and X for each respective face

Loading condition

• The plate is fixed and the sphere is loaded or displaced onto the plate to a max distance of 4mm along negative y axis and retracted back.

Analysis settings

• Since the sphere must be retracted back to visualize the plasticity in the plate, a total of 5 steps are created where in mid way the max displacement of sphere is about 4mm

RESULTS

Equivalent stress

Equivalent strain

Directional deformation in plate

Von mises stress in plate

Equivalent strain in plate

CONCLUSION

Hence the sphere pressing over a plate modeled with a non linear material was analysed and the required stress, strain variables were extracted as results.