Pin Connectors - Internal Representation

SOLIDWORKS Simulation represents internally a pin connector as a beam with a specified axial or rotational stiffness. Each end node of the beam is located at the centroid of the connected cylindrical face (or shell edge).

For a rigid connection type, rigid bar elements connect the beam end nodes to the cylindrical face nodes. All faces connected to the pin remain coaxial under loading, and maintain their original shape. These cylindrical faces can move as rigid bodies relative to each other depending on the axial and rotational stiffness characteristics of the pin connector. Because of the introduction of rigid regions, you may observe stress hot spot areas near the pin connector. Stress hot spots decrease gradually with distance, until they disappear in regions about one diameter away from the cylindrical faces.

For linear static studies only, you can select a distributed coupling formulation for pin connectors. Distributing coupling constrains the motion of the nodes of the attached cylindrical faces (coupling nodes) to the translation and rotation of the beam end node (reference node) in an average sense. A distributed connection allows the coupling nodes of a cylindrical face to move relative to each other. The distributed connection type produces more realistic stress and displacement fields at the vicinity of pin connectors.

A pin's axial stiffness defines the relative axial movement between the cylindrical faces (or circular edges) connected to a pin. A pin's rotational stiffness defines the relative rotational movement between the cylindrical faces (or circular edges). For a pin connecting more than two cylindrical faces or edges, the software redistributes the axial and rotational stiffnesses based on each pin segment's geometric characteristics (such as sectional area, polar moment of inertia, and length). A pin segment connects two consecutive cylindrical faces and has two end joints. Each pin joint is located at the centroid of the connected cylindrical face or circular edge.

For example, for a single pin definition connecting four cylinders of a hinged plate, as shown below, the solver calculates and lists the pin forces at four pin joints. Each pin joint is located at the centroid of each cylindrical face connected to a pin.

The software lists four forces per connector joint with respect to the pin's local coordinate system. An image of a pin's cross section with the forces calculated at a joint is shown.

• F_A = axial force across the pin's cross section

  A positive axial force indicates that the pin segment is under tension; a negative axial force indicates compression. The software reports the loads acting on a pin segment as pin connector loads at the pin joints. No balance of loads for the pin segment is considered for the listing of connector loads at the joints.

• F_V = shear force across the pin's cross section
• M_b = bending moment
• T = Torque

For pin joints that are common to consecutive pin segments, for example joint 2 in the figure below, the solver calculates two sets of pin connector forces for the left and right side of the common joint. The image illustrates a cross section of a pin connector with two pin segments (blue color) attached to three cylindrical faces..

The radius of a pin connector, R, is the radius of the cylindrical face or circular edge attached to the pin. Pin segments of a single pin connector definition can have different radiuses.

The solver calculates the von Mises stresses for the left and right side of the common joint. The software compares the von Mises stresses, and lists the set of pin forces (from the left or side side) that yield the highest von Mises stress.

The von Mises stress for a general plane stress case is given by:

, , ,

For the pass/no pass safety check of a pin connector, the software selects the pin joint with the maximum combined loads based on the von misses stress criterion to evaluate the factor of safety of the pin. See topicSOLIDWORKS Simulation Help: Pin Connector - Safety Check