Using spectral finite elements for parametric analysis of the vibration reduction index of heavy junctions oriented to flanking transmissions and EN-12354 prediction method

Abstract

The vibration reduction index of heavy junctions is predicted by means of a model based on spectral finite elements. This is equivalent to a finite element method but faster and with smaller computational costs. This advantage is used in order to perform a parametric analysis of the vibration reduction index for several junction types: T-shaped, L-shaped and +-shaped. The influence of several parameters such as: damping, junction dimensions or the mass ratio on the vibration reduction index is observed. The study is focussed to provide data and guidelines oriented to the EN-12354 design method for flanking transmission in buildings.

Catalogue of Vibration Reduction Index Formulas for Heavy Junctions Based on Numerical Simulations

“…The option here is to leave this aspect free and allow in-plane (longitudinal and transverse shear) waves to play their role if this is the case. The SFEM numerical model details as well as validations were presented in [13]. The numerical model, based on shell Spectral Finite Elements (SFEM [16][17][18]), is an efficient alternative to solve the elastodynamic problem in structures composed of extrusion symmetry shells in the frequency domain.…”

“…A more general and large comparison was done in the framework of [14] where it was compared with wavebased models and K ij computations done with other FEM software. The model was also compared with K ij measurements on real junctions made in the laboratory [13].…”

“…As shown in [9][10][11] it is not easy to define an error-free environment to compute or measure the vibration reduction index. In any case, there are evidences that if the prediction formulas in the Annex E [1] are compared with models of the isolated junction based on Finite Elements (FEM [12]), semi-analytical wave approach [8] or spectral elements (SFEM [13]) some differences are found. These differences 2 are important in the following aspects:…”

“…For these reasons, recent researches [8,[12][13][14] are trying to develop updated formulas that can be used to predict K ij with more details. Three different frequency ranges are defined: (i)low, from 50 Hz to 200 Hz; (ii)mid, from 250 Hz to 1000 Hz and (iii)high, from 1250 Hz to 5000 Hz.…”

“…The main goal of the current research is to extend the work presented in [13] to other junction types that are important for building industry but are not considered in the Annex E: H-shaped junctions, L or T junctions not forming a right angle, asymmetrical T-junctions , asymmetrical X-junctions. The data corresponding to the SFEM simulations in [14] are used in order to have reference values and regression curves for the standard L, T and X-junctions.…”