1
Download Design Sensitivity and Optimization User`s Guide
Transcript
Chapter Example Problems Chapter 7: 7: Example Problems Equation 7-14. We will assume thin-walled tubular members with a diameter-to-thickness ratio of approximately 100. Under this condition, the cross-sectional area A is nearly equal to Equation 7-15. and the area moment of inertia can be approximated by Equation 7-16. Since cross-sectional areas are chosen as design variables, we seek to express the member buckling stresses as functions of member areas as follows: Equation 7-17. For the buckling stress constraints to be satisfied, the member stresses must not be more compressive than σb , that is, Equation 7-18. where σb is a negative quantity, representing a compressive stress. Since the constraint in the form of Eq. 7-18 can't be used directly on a DCONSTR entry (the bound is a function of the design variables), we can first normalize the expression as Equation 7-19. 7-46 Design Sensitivity and Optimization User's Guide
