MechEng275
Mechanical
- Aug 2, 2024
- 1
looking for help on how to conduct an analysis with the following scenario:
A 0.25in thick vertical aluminum baseplate (plate a) has 4x tapped thru all #6 holes of spaced out in a rectangle pattern with dimensions of 4.5in width 3.5in height.
Each one of these tapped holes has a hex standoff inserted into the #6 tapped holes at a depth of about .2in.
The standoffs are 6-32 thread 1in long 0.25in hex width stainless steel male / female standoffs from McMaster Carr.
At the female end of these standoffs, there is a second plate (plate b) which is bolted into all four standoffs.
This plate weighs 5lb.
Plate b is secured to the standoffs using 6-32 pan head screws which insert about 0.25 into the standoff threads.
I am trying to figure out how to calculate the max weight plate b can be before the standoffs rip out of the tapped holes.
To me, it seems to be a two part analysis of the bending stress a point load at distance 1in causes and then the thread failure due to this point load.
I tried looking up beams and bending stress but most examples consider beams as a fixed end to the wall.
This lead me to trying to use max bending stress of M*c/I but it did not account for thread rip out.
I also tried looking into tensile strength and shear strength but all these consider the shear force acting on a bolt with a nut on the other end.
Tensile was only in the axial direction. Shear was only shown when two plates were clamped together by the bolt.
Thanks in advance
A 0.25in thick vertical aluminum baseplate (plate a) has 4x tapped thru all #6 holes of spaced out in a rectangle pattern with dimensions of 4.5in width 3.5in height.
Each one of these tapped holes has a hex standoff inserted into the #6 tapped holes at a depth of about .2in.
The standoffs are 6-32 thread 1in long 0.25in hex width stainless steel male / female standoffs from McMaster Carr.
At the female end of these standoffs, there is a second plate (plate b) which is bolted into all four standoffs.
This plate weighs 5lb.
Plate b is secured to the standoffs using 6-32 pan head screws which insert about 0.25 into the standoff threads.
I am trying to figure out how to calculate the max weight plate b can be before the standoffs rip out of the tapped holes.
To me, it seems to be a two part analysis of the bending stress a point load at distance 1in causes and then the thread failure due to this point load.
I tried looking up beams and bending stress but most examples consider beams as a fixed end to the wall.
This lead me to trying to use max bending stress of M*c/I but it did not account for thread rip out.
I also tried looking into tensile strength and shear strength but all these consider the shear force acting on a bolt with a nut on the other end.
Tensile was only in the axial direction. Shear was only shown when two plates were clamped together by the bolt.
Thanks in advance