Contact Sets in SOLIDWORKS SIMULATION

Simulation Contact Set

SolidWorksSimulation of assemblies or multi bodies requires the application of contact sets to define the interface between two objects.  If the contact sets are not defined properly we will obtain incorrect results.

Consider a simple weldment framed structure with a steel plate sitting on top.  

This weldment is fixed at the end of each leg and has a load applied to the plate on top.

By default, SolidWorks Simulation treats weldments as beam elements and the plate on top as a solid element.  As such we have two different element types in this analysis; therefore we need to define a contact set.  As an option we can use the “automatically find contact set” function by selecting a beam element and the plate.  The software will find the connecting surface where you may apply a condition, in this case bonded.  This is repeated for all four faces.

Upon closer inspection, we find those contact sets to be a face to face contact

Following the creation of the contact sets we can mesh our model and run the analysis

However in doing so will result in an error message. 

This is because the contact set defined was incorrect.  When the contact sets were created they were treated as faces, however since this is a solid to a beam element, we need to select the beam element contact set under “Type”.  By redefining all four contact sets, remeshing and running the study, we now have the correct results.

How to use "Curve through XYZ Points"?

Curve through xyz points

Data can be provided to the designer in a variety of ways from contract drawings, field measurement, word of mouth etc.  In the case of field measurement or established geometries, the data can come in the form of a plotted coordinate system. 

Let us consider the profile of an airfoil.  The geometrical features of an airfoil effect the flow and thus performance of the airfoil in operation.  It is important to model the geometry as accurately as possible.  The geometry is given in the form of an x-y coordinate system.  

It is worth noting that an additional column was added with all zeros in order to represent the dimensions for the Z plane.  The three column as given in excel format is not as useful, therefore we can copy the data by selecting the columns and selecting copy and paste it in a text document.

Save the text document since you will need to select it soon.

 Next we can start a new part in SolidWorks.  In order to bring the airfoil into SolidWorks you can sketch individual points and draw a spline connecting all the points.  This manual method is repetitive, labor intensive and time consuming.  A more efficient method would be to use the “Curve through XYZ Points” tool from the feature tab.

After selecting “Curve through XYZ Points”, click on browse and select the text file with the coordinates that was created.

  Upon selection you should see the points and data values populating the X, Y and Z coordinates.  Select “OK”.

  Now you should have a full accurate curved geometry that was constrained by the X,Y and Z coordinates that were imported.  Creating this curve using this method is significantly quicker than manually plotting each point and connecting them with a spline.  “Curve through XYZ Points” is one of many features that makes solid modeling faster and more efficient in SolidWorks.

Surfacing Tool in SOLIDWORKS

Simple Surface

Basic geometric shapes such as cubes and cylinders are easily defined however; 3D CAD software can do much more.  When a designer takes advantage of the 3D software capabilities, more complex shapes may be created and defined. 

  Consider a complex feature such as a compound curve.  Compound curves may be defined in SolidWorks using the surfacing tool.  In order to define this curve it must be constrained using three sketches.  The image below contains a sketched curve on the Front, Right and Top Plane.  Please note that the curve is sketched in a solid line whereas parts that do not define the curve are kept as construction lines.

Each curve may be modified to suit your chosen geometry.  The numerical values in this example are arbitrary however note that each curve shares a termination point from start to finish.

Next, activate the surfaces tab and select the boundary surface tool.  This tool creates a surface within the bounded conditions.  In this case the bounded conditions will be the sketches.  Under Direction 1 tab, select the two sketches on the Right and Front Plane.

Please note that the curve as shown is incomplete since the surface is only bound by the two sketches as reflected in the preview.  The bottom edge of the surface needs to follow the contour as outlined on the Top plane sketch.  To do so, activate Direction 2 and select the top plane sketch.

Now the compound curve is properly bound by all three sketches.  We may now accept and apply this feature

A fully defined compound curve surface is now defined.  This surface may now be used to complete a part or work as a simplified model for an FEA analysis.  The tools to create 3D parts such as compound curves are all available in SolidWorks.