What types of stresses are present on the bolted plate in this project?

[Stefan]

My partner and I are arguing over what types of stresses are present on a point of our project. We must calculate the stress by hand using Von Mises eq uations. The picture shows a diagram of what's going on. We are calculating the stress on the mounting plate from the quarter of the motors weight distributed over the motor footprint as well as the torque loading transferred from the bolt. Note that the shim is used for bolt alignment and the scrap metal is meant to protect the mounting plate from damage by the tightening of the bolt. Both are held in place by the same bolt. I am arguing that only normal stresses are present because all loading is applied normal to a surface. My partner is arguing that the loading produces shear stress because the downward force of the loading opposes the upward force from the stiffness of the plate.

Update: forgot to mention that we are solving for the stress at the point where the bolt meets the mounting plate.

 

[JBA]

I don't really understand the torque arrows on your drawing. Other than during tightening of the bolt, the mounting plate only experiences a compressive bearing stress in the scrap metal contact area and some minor surface shearing around the perimeter of the scrap metal, both due to the bolt installation tension alone.

 

[Tom.G]

I wonder where the force from the "Distributed Load" is counteracted; for instance is the Mounting Plate a cantilever beam, simply supported beam, a diaphragm or...?
Definitely not my area, so please ignore if irrelevant.

 

[JBA]

It depends upon what type of supports and where the supports for the mounting plate are located that determines the type of analysis for the distributed loading on the plate.

Since your drawing indicates a downward distributed loading and the bolt loading,apart for its installed tension, would only be a factor for upward loading on the mounting plate.

 

[JBA]

Addendum:
At this point you show an isolated area of the plate that basically floating in air. What you need to do is create a drawing of the entire supporting plate will all of the motor bolting locations and all of the supports for the mounting plate. With regard to the loading, while the total weight of the motor is one load vertical downward load, the torque of the operating motor will also be a load factor for both the bolts, mounting plate and its support connections. The result of the shaft torque loading on the motor is going to be a vertical downward load on the mounting bolts, mounting plate and plate supports on one side of the motor and a vertical upward force on those items on the opposite side of the motor to resist that torque.