A hybrid Approach for Static Progressive Damage Assessment of a Countersunk Bolted Composite Component

摘要

This paper illustrates a hybrid modeling approach based on the combined discrete crack network (DCN) and continuum damage model (CDM) for static failure prediction of a countersunk bolted composite component. In order to characterize the hole elongation and hydrostatic stress induced residual stiffness and strength, an advanced CDM approach is developed to simulate the progressive failure of a single shear bearing specimen and a bearing and bypass specimen. This approach was applied successfully for the blind prediction of various tests conducted under the Composite Airframe Life Extension (CALE) Call 2 program. Given the complex geometry associated with a countersunk bolt, capability extension of our existing DCN approach was accomplished by updating the kinematic description of a slanted matrix crack along with its cohesive injection on the inclined crack surface. A hybrid approach was developed by integrating the advanced CDM method with the updated DCN method for the progressive damage prediction of a bolted composite joint. Using the hybrid modeling approach, the complex bearing failure mode is captured by CDM description in the vicinity of the bolt hole while the discrete damage initiation and propagation is simulated using the DCN outside the bearing zone. The results of single shear bearing (SSB) tests show the validity of the hybrid approach in failure prediction of composite bolted joints.