Why Effective stress is more at fixed support ends?

- December 26, 2018 at 11:09 am
  
  JL1234
  Subscriber
  
  Why effective stress is always more at fixed support?
  
  See the attached image please
- December 26, 2018 at 2:09 pm
  
  Sandeep Medikonda
  Ansys Employee
  
  Because the complete reaction force is accounted for at the fixed end and the moment acting is maximum here.
- December 26, 2018 at 2:12 pm
  
  peteroznewman
  Subscriber
  
  This looks like a cantilever beam of uniform cross-section with a load on the other end, a distance L from the fixed end. Let's call the load F, which is a downward force applied to a horizontal beam.
  
  A free body diagram of this would show at the fixed end an upward force of F and a moment of FL. You can think of the moment FL as two horizontal forces on the fixed end of the beam, the force on the top pointing to the left, and the force on the bottom pointing to the right. The horizontal force at the end face is supported by internal forces inside the beam along the full length of the beam. The internal horizontal forces are a maximum at the fixed end and linearly reduce to zero at the end where the load is applied. This is why the stress is always more at the fixed support.
  
  Regards,
  Peter