Where Fn is the force in the nth member and An and Ln are its cross - sectional area and length.
Let W be the total load, the total load carried will be the sum of all loads for all the members.
Therefore, each member carries a portion of the total load W proportional of EA / L value. The above expression may be writen as
if the length of each individual member in same then, we may write Thus, the stress in member '1' may be determined as s1 = F1 / A1
hus, the stress in member '1' may be determined as s1 = F1 / A1 Determination of common extension of compound bars: In order to determine the common extension of a compound bar it is convenient to consider it as a single bar of an imaginary material with an equivalent or combined modulus Ec. Assumption: Here it is necessary to assume that both the extension and original lengths of the individual members of the compound bar are the same, the strains in all members will than be equal. Total load on compound bar = F1 + F2+ F3 +………+ Fn
where F1 , F 2 ,….,etc are the loads in members 1,2 etc
But force = stress . area,therefore
s (A 1 + A 2 + ……+ A n ) = s1 A1 + s2 A2 + ........+sn An Where s is the...