Low velocity impact behavior of composite sandwich panels

Composite sandwich structures are susceptible to low velocity impact damage and thorough characterization of the loading and damage process during impact is important. The objective of this work is to study experimentally the low velocity impact behavior of sandwich panels consisting of woven carbon/epoxy facesheets and a PVC foam core. Instrumented panels were impacted with a drop mass setup and the load, strain, and deflection histories were recorded. Damage was characterized and quantified after the test. Results were compared with those of an equivalent static loading and showed that low velocity impact was generally quasi-static in nature except for localized damage. A straightforward peak impact load estimation method gave good agreement with experimental results. A contact force-indentation relationship was also investigated for the static loading case. Experimental results were compared with analytical and finite element model analysis to determine their effectiveness in predicting the indentation behavior of the sandwich panel.