A Damage Model for Sandwich Plate with Viscoelastic Core in three-Points Bending Fatigue Experiments

摘要

In three-points bending fatigue experiments of sandwich plate with visoelastic core and steel facplates, recovering effects of fatigue life are found for its viscoelastic properties of the core. If the fatigue experiment is interrupted and rest for some time before reloading, there will appear a phenomenon that the deflection doesn't reach the former value immediately but after a specific time or cycles. From defining the damage variable D as the ratio between the differences of maximum allowable bending deflection and processing deflection in experiments, the fatigue damage equation are established. To considering the recovering effects, a formula which is similar with deflection of isotropic viscoelatic beam under concentrated load in midspan is introduced in damage equation. The experiments result shows that this damage model considering recovering effects can demonstrate the damage very well for sandwich plate with viscoelastic core. And the existing of viscoelastic core can increase the fatigue life of sandwich beam specimen.