514 Mechanics of Materials 2 §12.1 Table 12.1.Values of dA for curved bars. Cross-section (a】Rectangle bloge d (N.B.The two following cross-sections are simply produced R。 by the addition of terms of this form for each rectangular portion) axis of curvature R (b)T-section R。 oilo.(点）+loe(年a) d11 R (c】I-beom b3+ d3 R。 (t)+e,(+)+与（） (d)Tropezoid -b1+b2 d (e）Triangle As above (d)with b2 =0 As above (d)with b=0 d:2R R 2π{(R+R)-[(R+R)2-R2]/2)5 14 Mechanics of Materials 2 Table 12.1. Values of s - for curved bars. $12.1 Cross-section (a Rectangle bb I axis of curvoture -fRi (b T-section J? N.B. The two following cross-sections are simply produced iy the addition of terms of this form for each rectangular lortion) As above (d) with b2 = 0 As above (d) with bl = 0