Why, when calculating a bolt in tensile load, is it calculated as if it were a simple bar (Sigma=F/A) and the stress concentrator due to the thread is not taken into account? -
![Axial force measurement of the bolt/nut assemblies based on the bending mode shape frequency of the protruding thread part using ultrasonic modal analysis - ScienceDirect Axial force measurement of the bolt/nut assemblies based on the bending mode shape frequency of the protruding thread part using ultrasonic modal analysis - ScienceDirect](https://ars.els-cdn.com/content/image/1-s2.0-S0263224120304528-ga1.jpg)
Axial force measurement of the bolt/nut assemblies based on the bending mode shape frequency of the protruding thread part using ultrasonic modal analysis - ScienceDirect
![structural engineering - How to find the diameter of bolts in a flanged joint? - Engineering Stack Exchange structural engineering - How to find the diameter of bolts in a flanged joint? - Engineering Stack Exchange](https://i.stack.imgur.com/lIh8H.png)