An improved iterative technique for nonlinear inelastic time history analysis of single degree of freedom (SDOF) elasto-plastic system

It is observed that only the primary local mechanism that will form in an earthquake can be differentiated by the pushover analysis and it may not disclose other shortcomings that will be produced when the dynamic attributes of the structure change after the development of the principal mode mechanism. Subsequently, the pushover analysis can be implemented with the limitation that it ought to be supplemented with other assessment systems if higher mode effects are decided to be significant. Hence an effort is made to understand the spread of the plasticity by tracing the control points which essentially represent the state of transition in the elasto plastic model. The Newmark-β strategy for linear system frameworks is extended to nonlinear frameworks by utilizing the Newton-Raphson procedure by addressing the nonlinear state of motions is suggested. In LabVIEW programming, the nonlinear inelastic time-history responses predicted by the proposed program contrast well with those given by the mathematical problem taken for study. Adding to this, the bilinear isotropic hardening model is used to get plastic deformation results in ANSYS 17.0 using finite element method with mesh size as 0.4mm and 0.6mm. These simulations can help to understand how a frame acts when immediate repetitive loads act on the specimen. Furthermore, a small-scale steel frame prototype model was prepared for testing purpose to evaluate the validation of the developed algorithm The results of the analysis show that the nonlinear iterative approach offers an accurate solution with the experimental work, reflecting both the need for real plastic deformation and the action of catenary stiffness in steel structures.A more practical analysis technique for seismic design can be developed in future by contrasting with the presented program for verification.