The author proposes to obtain the dynamic stiffness for the multiply-supported structures condensed to the supports in the frequency domain using the modal approach. Thus, previously proposed approach, requiring the d...The author proposes to obtain the dynamic stiffness for the multiply-supported structures condensed to the supports in the frequency domain using the modal approach. Thus, previously proposed approach, requiring the dynamic inertia matrix for the single-base system, is extended for the multiply-supported systems. Modal analysis is performed twice： once for the structural model with one base fixed, then for the same model with all bases fixed. The applicability of the proposed approach is checked for a sample two-base system enabling analytical solutions both in precise and modal approaches. The format of the condensed dynamic stiffness in the frequency domain enables to combine finite-element-method （FEM） codes like ABAQUS and Soil-Structure Interaction （SSI） codes like SASSI or CLASSI in a complex to perform effective soil-structure interaction analysis.展开更多
Through classifying modal verbs from the semantic aspect and the pragmatic aspect, this paper discusses difficulties that students may encounter in modal verb learning. It indicates that modal verbs have complicacy, a...Through classifying modal verbs from the semantic aspect and the pragmatic aspect, this paper discusses difficulties that students may encounter in modal verb learning. It indicates that modal verbs have complicacy, and a deductive approach and inductive approach should intermingle as an appropriate method to improve students' accuracy in use of modal verbs.展开更多
文摘The author proposes to obtain the dynamic stiffness for the multiply-supported structures condensed to the supports in the frequency domain using the modal approach. Thus, previously proposed approach, requiring the dynamic inertia matrix for the single-base system, is extended for the multiply-supported systems. Modal analysis is performed twice： once for the structural model with one base fixed, then for the same model with all bases fixed. The applicability of the proposed approach is checked for a sample two-base system enabling analytical solutions both in precise and modal approaches. The format of the condensed dynamic stiffness in the frequency domain enables to combine finite-element-method （FEM） codes like ABAQUS and Soil-Structure Interaction （SSI） codes like SASSI or CLASSI in a complex to perform effective soil-structure interaction analysis.
文摘Through classifying modal verbs from the semantic aspect and the pragmatic aspect, this paper discusses difficulties that students may encounter in modal verb learning. It indicates that modal verbs have complicacy, and a deductive approach and inductive approach should intermingle as an appropriate method to improve students' accuracy in use of modal verbs.
