A method for estimating specimen tangent stiffness for hybrid simulation

Chung Chan Hung, Sherif El-Tawil

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Researchers have long recognized the importance and potential benefits of utilizing the tangent stiffness matrix of a test specimen in hybrid simulations employing implicit and mixed-integration schemes. However, the computation of the tangent stiffness matrix during testing has proved to be challenging, particularly for test specimens with more than one degree of freedom (dof). This paper presents a new methodology that is more straightforward and simpler than existing techniques for computing the tangent stiffness matrix of a multi-dof test specimen. The proposed method is combined with the operator-splitting method (OSM), and the capabilities, advantages and limitations of the new formulation are demonstrated through several examples. The accuracy, stability, and error propagation characteristics of the modified OSM are also studied theoretically as well as numerically. The research results show that the proposed algorithm provides results that are better than those produced via the regular OSM alone, especially for damped structures undergoing highly inelastic behavior during testing.

Original languageEnglish
Pages (from-to)115-134
Number of pages20
JournalEarthquake Engineering and Structural Dynamics
Issue number1
Publication statusPublished - 2009

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Earth and Planetary Sciences (miscellaneous)
  • Civil and Structural Engineering


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