Figure 10 — Coordinate System for Idealized 

 Prismatic Structure 



TENSION AND BENDING 



As in Appendix A.l, it is assumed that tlie distribution of tensile strain over the cross 

 section is linear in both y and z. Thus the axial stress in the tension-carrying material at 

 node i, which is located at y = y. , z = z . , is 



(a ). = B + Cy. + Dz. [1] 



^ XX 'l '' 1 1 



where the positive values denote tensile stress. 



By summing over all the nodes of the section, we get the following expressions for 

 tension and bending moments V^ , M , and M^ : 



V, = + SKJiA. = B2A. +CSy^A, + DSzA. 



My = + SKx)i^A^ = BSz.A^ + C2y.z.A^ + D2z.2A^ 



Mz = - ^ Kx). y^. = -B^iA; - C ly^^A^ _ d ly.z^A. 



[2]^ 



*AU summations given in section Tension and Bending are with respect to subscript i. 



61 



