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Protocols for tensile testing flexible unidirectional composite laminates



Amy E. Engelbrecht-Wiggans, Ajay Krishnamurthy, Faraz A. Burni, William A. Osborn, Amanda L. Forster


Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin layers of high performance yarns where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin polymer films. The armor is constructed by stacking the unidirectional layers in different orientations. To date, only very preliminary work has been performed to characterize the ageing of the binder resins used in unidirectional laminates and the effects on their performance. For example, during the development of the conditioning protocol used in NIJ Standard-0101.06 UD laminates showed visual signs of delamination and reductions in V50 after ageing. A better understanding of material property changes in UD laminates is necessary to comprehend the long-term performance of armors constructed for these materials. There are no current standards recommended for mechanically interrogating unidirectional (UD) laminate materials. This study explores methods and best practices for accurately testing the mechanical properties of these materials, and proposes a new test methodology for these materials. Best practices for ageing these materials are also described.
Journal of Visualized Experiments


Composite laminate, strip tensile testing, body armor, aramid, ultra high molar mass polyethylene.


Engelbrecht-Wiggans, A. , Krishnamurthy, A. , Burni, F. , Osborn, W. and Forster, A. (2019), Protocols for tensile testing flexible unidirectional composite laminates, Journal of Visualized Experiments, [online], (Accessed July 14, 2024)


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Created April 27, 2019, Updated May 20, 2020