Stress analysis on Bracket

Hi,

 

I have a concern regarding the stress analysis on the bracket I have designed.

 

The bracket is carrying Horn Antenna Assy which is then fixed to the Master Block . Then the entire Assy is purely under Gravity due to its own Mass.

 

The weight of the Assy is 3.5Kg including Bracket.

 

I have done some analysis on this assy applying gravity as loading condition and providing the Fasteners from the Connector facility in solidworks.

 

I have used AISI 304 Steel Alloy for the Fastener Material.

 

I am veryfing whether the Bolt assy is within the defined Factor of safety or not.

 

In case1: I have applied preload strength data in solidworks for bolts as 2.5Nm torque with deifned FOS of 2. In this case I got a factor of safety of ~5. Which is a good sign of strength.

 

In case2: I have applied preload strength data in solidworks for bolts as 4.2Nm torque with deifned FOS of 2. In this case I got a factor of safety of < 2. Which is not acceptable within this very small increase of torque value.

 

Can some give me some explanation whether I am performing the correct method for the analysis or not.

 

Appreciate the feedback.

 

Thanks

Vijay

SolidworksSimulation