SOLIDWORKS Simulation 2021 Improved Bonded Formulation

SOLIDWORKS Simulation 2021 has made changes to algorithms related to bonded interactions to improve the accuracy and stability of static, frequency and buckling studies.  There may be small gaps between the physical geometry that were not noticed.  In some cases the geometry may have no clearance, but an independent coarse mesh causes small gaps or interferences.

Here’s an example of two parts.  There is a complex spline cutting them in two, but all locations are physically coincident (no gaps or interference).  The black part is fixed on its flat sides.  The grey part has an angled force load attempting to pull it away.

SOLIDWORKS Simulation Study with Bonded Components

For exaggeration, the mesh was set to Draft quality and a coarse size.  While the geometry is properly coincident, using an independent mesh (incompatible) now have slight gaps and interferences between nodes.

SOLIDWORKS Simulation Mesh Gaps

Simulation 2020 global bonded interactions does not account for gaps by default.  When we attempt to solve the study, there is instability and the parts let go.

SOLIDWORKS Simulation 2020 Bond Not Held

Simulation 2021 automatically includes a 0.01% gap range for bonding, which is similar to the non-touching faces option in previous releases.  This accounts for variations in the coarse mesh and keeps a proper bond.  However improvements in the Simulation 2021 bonded formulation give better results than previous releases.  Here I matched the clearance/gap size.  Note how Simulation 2021 provides more realistic results even with a poor quality mesh.

SOLIDWORKS Simulation 2021 Displacement Results

In the end, the mesh itself was too coarse with draft quality.  If a refined high quality mesh was used, the bond would hold.  However this gives an visible representation of the improvements in Simulation 2021.