STRUCTURAL MECHANICS MODELING OF THE IMPACT OF A DOUBLE CANTILEVER BEAM

A Global/Local model is developed for the calculation of dynamic stres s intensity history resulting from the impact of a double cantilever b eam. The model separates the Global structural dynamics from the Local crack tip zone dominated by singular stresses. The Global model, cons isting of connected waveguides, describes the structural dynamics usin g spectral elements. The Local model, describing the crack tip behavio r, is based on an application of the J-integral that converts the dyna mic structural resultants directly into strain energy release rate. Pr evious work used this approach successfully for pure mode II deformati on; the present paper extends the modeling to mode I and mixed mode de formation. Of special concern is the local modeling of the elasticity and mass in the vicinity of the crack tip; structural mechanics modeli ng is combined with Hamilton's principle to properly address this ques tion. The accuracy of this approach is assessed by comparing it to a t wo dimensional finite element analysis.