Bending stress in Beams annotated

Erbil Polytechnic University Strength of Materials-I (STM303)
Erbil Technical College Dr. Feras Khlef
Civil Engineering Techniques Dept. First Semester 2021
Lecture 17
Bending stress in Beams
Th e b e nding m o m e nt “M” c a uses th e
m a terial within th e b otto m p ortion of th e
b ar to stretc h a nd th e m a terial within th e
to p p ortion to c o m press. C onse qu e ntly,
b etw e e n th ese tw o re gions th ere must b e
a surfa c e, c alle d th e n e utral surfa c e.

Lecture 17
m ax = th e m aximum norm al stress in th e
m e m b er, whic h o c c urs a t a p oint on th e
cross-se ction al are a farth est a w a y fro m
th e n e utral axis.
M = th e result a nt intern al m o m e nt, d etermin e d
fro m th e m etho d of se ctions a nd th e
e qu a tions of e quilibrium, a nd c alc ula te d
a b out th e n e utral axis of th e cross se ction
c = p erp e ndic ular dist a n c e fro m th e n e utral
axis to a p oint farth est a w a y fro m th e
n e utral axis. This is wh ere m ax a cts.
I = m o m e nt of in ertia of th e cross-se ction al
are a a b out th e n e utral axis
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Bending stress in Beams annotated

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