Abstract
Finite element (FE) method is usually used in the structure analysis problem. Towards the larger and complex structure of car body to establish FE model requires much time in analysis. Substructure techniques allow to reduce considerably time and work volume and to increase degree of accuracy of FE model. In this studies, we use SAP2000 to determine the stress of car body under the exiting force from random road roughness. The stress calculated by SAP2000 can be compared with that measured.