INFLUENCE OF IMPERFECTION IN LENGTH AND LOADING ON DYNAMIC RESPONSE OF TRUSSES UNDER HARMONIC LOAD

Abstract

In structural engineering, trusses are important for covering large-span structures. However, imperfections are often present in the manufacture and assembly of truss structures, particularly in terms of the length and loading. This article presents the influence of imperfection, both in length and loading, on the dynamic response of trusses under harmonic loads considering geometrical nonlinearity. To analyze trusses, the hybrid matrix of elements of the truss is established to solve dynamic equations by applying the Newmark integration and Newton–Raphson iteration methods. The authors continue to develop the previous study by investigation of the influence of two imperfect parameters of structures in terms of element length and loading. An incremental-iterative algorithm was developed, and a calculation programming routine in MATLAB software was written to illustrate the dynamic responses of trusses with imperfections under harmonic loading. The results obtained in this study verified the accuracy and effectiveness of the proposed approach in the analysis of trusses under harmonic loading. The numerical results show that when considering both length and load imperfection, the dynamic response of the trusses is significantly different in comparison to the case of consideration of length imperfection separately. With consideration of both imperfect parameters in length and loading, the critical load is significantly decreased. From there, it can be concluded that, in the dynamic analysis of trusses, all possible imperfect parameters, especially in element length and loading, must be considered.