WORKSHOP 12 ASSEMBLY MESHING, TENSION FITTING · The fitting is made of Aluminum Alloy 7075-T7351 with an elastic ... PAT302, Workshop 12, December 2004 ... General Procedure

WS12-1PAT302, Workshop 12, December 2004Copyright2004 MSC.Software Corporation

WORKSHOP 12

ASSEMBLY MESHING, TENSION FITTING

2500 lb



ASSEMBLY MESHINGTENSION FITTING

Problem Description A bathtub tension fitting analysis is required A 2500 lb axial load is transferred from the large bolt into the

tension fitting. This load is reacted by three smaller bolts. Based on hand calculation it is expected that the stress gradient will

be higher in the end pad area where the load causes plate bending.A finer mesh is required in this area

The stress is expected to be lower away from the end pad area andtherefore, a coarser mesh will suffice

The fitting is made of Aluminum Alloy 7075-T7351 with an elasticmodulus E = 10e6 psi and a Poisson’s ratio = 0.33


General Procedure Create a new database and import the Parasolid XMT file

bathtub.xmt. Create an annular solid face for the applied surface load by

creating a primitive cylinder with a radius 0.4375 in. Imprint thecylinder onto the end pad area.

Create a plane to break the solid into two parts, so that mesheswith different densities can be created in each part of the model.Break the solid, then TetMesh the parts.

Equivalence and look for any element free edges. Apply the total load to the annular solid face. Constrain the cylindrical solid faces of the three small bolt holes. Create material and element properties. Run the Analysis and access the results. Display the Results.



Import and edit the geometry for the application of theapplied load Create a database Import the Parasolid file bathtub.xmt Create a primitive cylinder, with radius 0.4375, concentric to the

hole indicated Imprint the new solid onto the model then delete it

Shown here is thesolid after makingthe imprint


Create the cylinderconcentric to thehole.


Edit geometry for creating two parts for meshing As indicated earlier the end pad area is expected to have a higher stress

gradient than the remainder of the model, so a finer mesh needs to becreated there. A coarse mesh will be created elsewhere.

Create a plane using [0 0 0.625] and <0 0 1> , and break the solid with it. There are now two solids for which different size elements can be created.

Beforebreaking

Afterbreaking

End Pad



Mesh the two solids using different element sizes. Mesh the end pad solid with Tet10 elements. Use a GEL of 0.125 in. Mesh the remaining solid with Tet10 elements, this time using a GEL of

0.25 in. Make sure to set the toggle for Match Parasolid Faces to Yes

Equivalence the meshes under Finite Elements, and check for anyunconnected elements at the interface.

Illustrated here are themeshed solids. Note thatthe mesh is much finer inthe end pad area, whereasthe rest of the model has amuch courser mesh.



Create the load and constraints Apply the 2500 lb total load to the annular solid face of the tension

fitting Constrain the cylindrical solid faces of the bolt holes

Apply the totalload here

Constrain the surfaces here



Create the material and element properties for model As described in the general outline the model is made of

Aluminum 7075-T7351with the following properties: Elastic modulus E = 10e6 Poisson’s ratio = 0.33

Create the 3D solid element properties using Aluminum as the material

Run the analysis of the model Analysis: Analyze/Entire Model/Full Run



Results Note that the stress

gradient is higher inthe end pad area, aswas expected

Similarly, the stress inthe area of the boltholes is relatively smallcompared to that of theend pad

Close the file and quitPatran


WORKSHOP 12 ASSEMBLY MESHING, TENSION FITTING · The fitting is made of Aluminum Alloy 7075-T7351 with an elastic ... PAT302, Workshop 12, December 2004 ... General Procedure

Documents