definition of hogging momen

huangyhg

definition of hogging moment
i've run across the term "hogging moment" a few times before.  i do not know what the "hogging" indicates.  anyone?
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the opposite of sagging moment.  different sign conventions are used by engineers, so the terms positive and negative moments can be confusing.  for a beam with fixed ends, sagging moment occurs at midspan and hogging moment occurs at the ends.  
consider a really big ship riding at the waves. if the ship is supported by two waves at bow and stern, it sags in the middle. if the ship is suppoerted on a wave in the middle, it is called a hog, with both ends bending downward.
merriam-webster defines it. used as a verb it means: to cause to arch. so for a continuous 3 bay/span beam, the arching at interior supports is "hogging".
as a previous poster says, hogging is the opposite of sagging.  a sagging moment is possibly more apparent to visual ... a sagging moment causes the middel of the beam to sag, tension in the lower surface and compression in the upper surface.  a hogging moment does the opposite, tension in the upper surface and compression in the lower surface.