January 27, 2016

Contact Connections - Part 2

Last blog we examined connectors in SolidWorks Simulation. Let’s review a few more commonly used contact sets; the bolts, pin and springs.

A Bolted connection is very common in connector design. Bolt connections are simulated in the software by a beam and rigid bar.  The beam resists only tension and allows pre-loading and the rigid bar connects the beam with the flange faces. Only a few parameters need to be defined for a bolt including the type (counterbore, counter sink, etc.), shank diameter, head diameter, pre-load conditions and bolt strength data.  The software does the calculations to determine the resultant axial force shear force and bending moments. The image below illustrates a typical Solidworks assembly that requires bolted connections:

bolted connections

Below is a detailed view of a piping bolted connection:

piping bolted connection contact sets

Pin connectors are also common connectors. In order to simulate pins, SolidWorks creates a beam element and allows rotation as well as translation between the bodies. In order to apply a pin connection you simply select the cylindrical face of the hole and enter the pin characteristics such as strength and resistance to rotation. The image below illustrates the pin connection of a pair of pliers:

pin connectors - contact sets

Spring connectors can be difficult to model in traditional FEA. The spring’s stiffness has to be divided by the number of nodes on each face and uneven mesh distribution can affect the spring stiffness. SolidWorks makes spring connectors easy by allowing designers to apply the connector either to parallel faces, concentric cylinders or even between vertices. Springs appear only in common projected areas between faces to avoid unintended moments. Designers may define tension-only, compression-only or tension-compression springs. Examples for each respective definition would be a rope, bumper and a typical spring. For each case the user may define a stiffness value as well as a pre-load parameter. Below is an example of a spring connector between two parallel faces:

spring connectors

Applying the correct connection ensures the part reacts properly under loading conditions. Defining connections between parts is made easy using SolidWorks Simulation.  

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