Finite Element Motion Analysis of Furniture under Seismic Excitation
Abstract
In big earthquakes, improperly secured furniture could move violently and
may give high risks of human injuries, even when the building itself has small
damages. Many tumbled furniture such as chairs and desks in schools could
become fatal obstacles that obstruct children from evacuating. Therefore, it is
important to know the overturning behaviors of furniture under seismic
excitations, as well as the behaviors and damages of the building itself. The
objective of this research is to develop a finite element code to analyze
motion behaviors of furniture under seismic excitations. To realize various contact phenomena during seismic excitations, the ASI
(Adaptively Shifted Integration)-Gauss code including frictional contact
algorithm based on the sophisticated penalty method was adopted. This code
was originally developed to analyze collapse behaviors of buildings with
phenomena such as fracture and contact. First, some shake-table tests of a chair and a desk used in schools were
performed. After validating numerical results with the experimental results,
we carried out an analysis of a model with chairs and desks arranged in
a classroom. Earthquake countermeasures depending on a difference in the
coefficients of dynamic friction are then discussed according to the numerical
results. Secondly, we simulated the motions of furniture arranged in an upper
floor of a medium-rise reinforced concrete building. Two types of furniture
on the upper floors of the building with different constraint conditions
were assumed. We simulated the differences in the behaviors of the furniture
with and without earthquake countermeasures.