骨組構造の最小重量設計に関する研究 (I)

抄録

A new approach to minimum weight design of multi-story plane portal frames is proposed by basing on “Mechanism Method”.
The principle of this method is indicated as follows ;
(A) FORMULATION OF ALL THE POSSIBLE COLLAPSE MODES OF A GIVEN FRAME
All the possible collapse modes and the corresponding evaluation of virtual work of a given frame can be automatically formulated through simple combination of basic data for mechanisms of two elementary structural aggregates. Therefore the ultimate load can be easily determined by computing the smallest limit load under given Mp values.
(B) SCREENING OF THE RESTRAINING INEQUALITIES OBTAINED IN (A)
The number of restraining inequalities obtained in (A) which may increase so fast with the structural complexity can be effectively reduced by computing the limit load of each mechanism. for appropriately assumed Mp values and selecting a number of important inequalities which may be operative in the final solution of minimum weight design through comparison and arrangement of these collapse loads in the order.
(C) DETERMINATION OF LOWER BOUND SOLUTION BY LINEAR PROGRAMMING UNDER THE RESTRICTED NUMBER OF INEQUALITIES OBTAINED IN (B)
A lower bound solution of a given problem can be determined by the well established “Dual Simplex Method” in Linear Programming under the restricted number of inequalities obtained in (B).
These three steps of calculation can be combined, connected and looped into as unified process of automatic computation of which modern electronic digital computers are capable.
It is emphasied scale of the problems to be solved will not be practically influenced by the size of a digital computer to be used.