The bolt cylindrical surface should be the contact surface, and the bolt section should be assigned to the contact elements.

Coordinates of the axis data points (required for SECDATA) should be on the bolt axis and defined in the global coordinate system.

In order to achieve better accuracy, the mesh size in the thread region should be less than the pitch distance.

We recommend you use the projection-based contact detection method (KEYOPT(4) = 3).

This technique is valid only for standard, straight threads. It is not applicable for nonstandard threads such as tapered threads or buttress threads.

The maximum stress in the thread region may vary with mesh density. However, the overall stress distribution remains similar in pattern.