The Development of a Low Velocity Impact Methodology for Hybrid Material Systems
Final rept. Apr 80-Apr 81
VOUGHT CORP ADVANCED TECHNOLOGY CENTER DALLAS TX
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The development of a design methodology for hybrid structures which describes the extent of damage and associated failure modes due to low velocity impact has been undertaken. Hybrids can provide a synergistic improvement in damage resistance caused by foreign body low velocity impact over graphiteepoxy material and when properly designed, enhance the visual and NDI damage detection threshold of the baseline material. Improvements in the visible and NDI damage detectability threshold of graphiteepoxy material, subject to low velocity impact, via proper placement and use of Kevlar plies and metallic coatings within this baseline material were exhibited. Correlation between the math model and the extent of both visible and invisible damage test panels experienced when subjected to low velocity impact were used to validate the model. Residual strength tests of damaged panels were run to quantify the static strength reduction experienced in the panel due to varying levels of visible and invisible damage. Development of the math model was based upon physical parameters identified through experimental testing. These included transverse impact of hybrid and graphiteepoxy panels and tensile tests of the target materials at elevated strain rates. High speed photography of the impact event on the composite panels was used to provide the dynamic modes of failure for use in model.
- Laminates and Composite Materials
- Numerical Mathematics
- Test Facilities, Equipment and Methods