Engineers Corner: Calculate the Location of the Plastic Neutral Axis for an Asymmetrical Steel Section

Assumption: Top flange is in compression and bottom flange is in tension.

Definitions:

PNA:    The plastic neutral axis is defined as the axis that divides the cross section such that the compression force from the compression area is equal to the tension force from the tension area. Its’ location is denoted by, y_p.

b:         Width of the flange

t_f1:            Thickness of top flange

t_f2:            Thickness of bottom flange

t_w:        Thickness of web

d:         Total depth of section

T_c:        Compression force

T_f:        Tension force

Yield Strength of steel = 350 MPa

Solution: