Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

292 CHAPTER 8 Columns

Fig. P.8.14

Fig. P.8.15

P.8.16 Apin-endedcolumnoflength1.0mhasthecrosssectionshowninFig.P.8.16.Iftheendsofthecolumn
arefreetowarp,determinethelowestvalueofaxialloadwhichwillcausethecolumntobuckle,andspecifythe
mode.TakeE=70000N/mm^2 andG=25000N/mm^2.

Ans. 5527N.Columnbucklesinbendingaboutanaxisintheplaneofitsweb.

Fig. P.8.16

P.8.17 Apin-endedcolumnofheight3.0mhasacircularcrosssectionofdiameter80mm,wallthickness2.0mm,
andisconvertedtoanopensectionbyanarrowlongitudinalslit;theendsofthecolumnarefreetowarp.Determine
thevaluesofaxialloadwhichwouldcausethecolumntobucklein(a)purebendingand(b)puretorsion.Hence,
determinethevalueoftheflexural–torsionalbucklingload.TakeE=70000N/mm^2 andG=22000N/mm^2.
Note: The position of the shear center of the column section may be found using the method described in
Chapter16.

Ans. (a) 3.09× 104 N, (b) 1.78× 104 N,1.19× 104 N.