Applies To
	Product(s):	STAAD.Pro
	Version(s):	All
	Environment:	N/A
	Area:	Postprocessing workflow
	Subarea:	N/A
	Original Author:	Bentley Technical Support Group

In the Postprocessing workflow - Layouts menu - Plate Stress, there are two options called Max Top and Max Bottom. Are these direct stresses or flexural stresses?

These are the principal stresses SMAX and SMIN. Principal stresses are a blend of axial stresses (also known as membrane stresses SX and SY), bending stresses (caused by MX and MY) and inplane shear stresses (SXY). Since the bending stresses have distinct signs for the top and bottom surfaces of the element, the principal stresses too are distinct for top and bottom. The derivation for principal stresses is shown in example 18 of the STAAD Examples manual.