Predictor-corrector procedures for pseudo-dynamic tests
Purpose - To propose novel predictor-corrector time-integration algorithms for pseudo-dynamic testing. Design/methodology/approach - The novel predictor-corrector time-integration algorithms are based on both the implicit and the explicit version of the generalized-a method. In the non-linear unforced case second-order accuracy, stability in energy, energy decay in the high-frequency range as well as asymptotic annihilation are distinctive properties of the generalized-a scheme; while in the non-linear forced case they are the limited error near the resonance in terms of frequency location and intensity of the resonant peak. The implicit generalized-a algorithm has been implemented in a predictor-one corrector form giving rise to the implicit IPC-p(infinity) method, able to avoid iterative corrections which are expensive from an experimental standpoint and load oscillations of numerical origin. Moreover, the scheme embodies a secant stiffness formula able to approximate closely the actual stiffness of a structure. Also an explicit algorithm has been implemented, the EPC-p(b) method, endowed with user-controlled dissipation properties. The resulting schemes have been tested experimentally both on a two- and on a six-degrees-of-freedom system, exploiting substructuring techniques. Findings - The analytical findings and the tests have indicated that the proposed numerical strategies enhance the performance of the pseudo-dynamic test (PDT) method even in an environment characterized by considerable experimental errors. Moreover, the schemes have been tested numerically on strongly non-linear multiple-degrees-of-freedom systems reproduced with the Bouc-Wen hysteretic model, showing that the proposed algorithms reap the benefits of the parent generalized-a methods. Research limitations/implications - Further developments envisaged for this study are the application of the IPC-p(infinity) method and of EPC-pb scheme to partitioned procedures for high-speed pseudo-dynamic testing with substructuring. Practical implications - The implicit IPC-p(infinity) and the explicit EPC-P(b) methods allow a user to have defined dissipation which reduces the effects of experimental error in the PDT without needing onerous iterations. Originality/value - The paper proposes novel time-integration algorithms for pseudo-dynamic testing. Thanks to a predictor-corrector form of the generalized-a method, the proposed schemes maintain a high computational efficiency and accuracy.
structures tests and testing programming and algorithm theory numerical analysis