2014, Teoria e Pesquisa
The index U* was introduced in the previous paper by the authors to show the load paths in a structure. The complementary index U** to U* has also been studied to ascertain the conditions of distributed loading. The main problem encountered in calculating U* and U** is the high computation time required-especially for the actual application of large scale FEM models. In this study, we propose two methods for reducing the time taken by FEM calculations to obtain the U** distributions. In the first method, the essential term is extracted from the global form of the flexibility matrix for the calculation of an internal flexibility matrix in each node. Since the first method cannot be utilized for large-scale commercial FEM codes, a second method is introduced. In the second method, three independent inspection loadings are applied to each node of a structure. In this operation, the multi-displacement condition is converted into the multi-loading condition. After calculating the cab structure for a heavy-duty truck cab using the second method, we obtained the result that the reduction in time required for calculations was better than 90 percent.