Application Of The Smeared-embedded Softening Hinge Model In Non-linear Analysis Of Structure

Plastic hinges form at the end of the column and beam of the structure at failure. The behaviour of plastic hinges have great influence of non-linear analysis of structure. This work present non-linear analysis of structure with a new smeared-embedded plastic hinges model. It is applicable when the softening effects of plastic hings is taken into account. This new smeared-embedded softening hinges, on one hand, similarly to the embedded hinge model, the softening hinge is described by a cohesive model between the stress resultants and the displacement jumps. On the other hand, the stress field in the element is evaluated from a constitutive relation at the cross-section level as in the classical smeared hinge model. Particularly, the displacement jumps are regarded as internal variables and can be determined at the material point level of the softening hinge. Therefore, it is not necessary to introduce the ad hoc penalty elastic stiffness, the extra degrees of freedom or the static condensation at the element level as in the embedded hinge model. Several representative numerical examples are presented, verifying that the proposed model is mesh-size objective. And we can get correct solution efficiently.Then this new softening hinge model is developed by taking into account elastoplasticity with both strain-hardening and strain-softening. We present the theoretical aspect and numerical implementation. Firstly, we derivate the constitutive relations of the softening hinges with hardening as well as softening effects.Then the new beam finite element enriched by smeared-embedded softening hinges is established. Besides the above characteristics, the proposed method also defines a very convenient framework for its numerical implementation. Standard finite elements of beams and well-developed algorithms for inelastic material models can be straightforwardly employed with minor modifications. Several representative numerical examples are presented to compare with the result of the softening hinge, the results are correct and correspond with reality.