ce132p structural theory 2
--MOMENT AREA METHOD
1-4
Developed by Otto Mohr
Later stated formally by Charles E. Greene in 1873
Provide semi-graphical technique in determining
the slope of the elastic curve
deflection due to bending
Advantageous:
Beam subjected to series of concentrated load
Segments having different moment of inertia
The change in slope between any two
points on the elastic curve equals the
area of the M/EI diagram between
these two points.
B/A is referred to as the angle of the tangent at B is measured with
respect to the tangent at A.
Angle is measured counterclockwise from tangent A to tangent B if
the are of M/EI diagram is positive.
Negative clockwise
Measured as radians
The vertical deviation of the tangent at a point
(A) on the elastic curve with respect to the
tangent extended from another point (B)
equals the moment of the area under the
M/EI diagram between the two points (A and
B). This moment is computed about point A
(the point on the elastic curve), where the
deviation tA/B is to be determined.
A B
B/ A tB / A
Determine the slope at points B and C of the beam.
E = 200 GPa and I = 360 x 106 mm4.
Ans. B = -0.00521 rad and C = -0.00694 rad
Determine the slope at point C of the beam.
E = 200 GPa and I = 6 x 106 mm4.
Ans. C = 0.112 rad
Determine the deflection at point C of the beam.
E = 200 GPa and I = 250 x 106 mm4.
Ans. C = -0.143 m
Next topic: CONJUGATE BEAM METHOD