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Impact and CSAI Analysis and Validation Using High Fidelity Test and Inspection Data

MARK PANKOW, BRIAN JUSTUSSON, JOSEPH SCHAEFER

Abstract


Currently, Progressive Damage and Failure Analysis (PDFA) methods are being developed to simulate the damage state as a result of impact and predict the residual strength of composite laminates. To date, these methods have shown success in predicting either the damage state or residual strength, but generally not both. The refinement of the PDFA methods to achieve success in both is limited due to availability of relevant test data with the resolution required to characterize damage state as a result of impact. In order to fill this gap the High Fidelity Database and Validation Protocols for Structural Failure Mode Characterization project sponsored by ONR (N00014-14-C-0128) is developing an extensive set of data to benchmark Compression Strength After Impact (CSAI) predictions using PDFA methods. The database provides high fidelity experimental and post-test inspection for a family of common laminates used in structural applications. The following laminates (10/80/10, 25/50/25, and 50/40/10) of IM7/5320-1 were impacted in accordance with the ASTM D7136 standard at 175 and 350 in-lb. During impact, high speed 3D Digital Image Correlation (DIC) was recorded of the back face deformation to determine the time-displacement history, deflection profile, and the onset of first ply cracking for two impact energies. At the completion of the test, the permanent deformation and damage state were measured by advanced Computed Tomography (CT) providing a ply-by-ply view of damage from the impact event. In this paper, the application of high fidelity experimental and posttest inspection data is demonstrated with a PDFA method.

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