Methods for dynamic testing of polymer-based composite materials
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When advanced polymer-based composite materials are to be used in aeronautical structural components, a design development program is generally initiated during which the performance of the structure is assessed prior to its use. Typically, the process of design starts with the analysis of a large set of simple small specimens and, when sufficient knowledge is acquired at this level, it is changed over to a more complex structure but carrying out fewer tests. This methodology is quite mature and well stablished for static loads. However, for intermediate and high dynamic loading conditions, the test methods are still under development and often limited to academic research levels, without any type of standardization even for basic material characterization. Indeed, the literature is very scarce, and, in some cases, there is no clear consensus between authors for a given property. This experimental limitation occurs in any associated task, which are the adequate definition of: specimens, test setup (test machine to be used, the instrumentation, and the clamping system), and the data reduction methods. Therefore, the advance in well-designed dynamic test methods is of current interest. The European Clean Sky 2 project “BEDYN - Development of a methodology (test, measurement, analysis) to characterize the BEhaviour of composite structures under DYNamic loading (GA. 886519)” is focused, in part, on the definition and execution of well-suited experimental tests at coupon level for a whole characterization of polymer-based composite materials under dynamic loading. A definition is purposed for each of the large number of material properties that must be characterized to later simulate a composite structure accurately (e.g., dynamic characterization of Mode I interlaminar fracture toughness, see [1]). The project also includes the definition and execution of small-size demonstrators such as Filled Hole Tension (FHT) and Bearing tests under dynamic loading. In the present communication, an overview of the test methods considered for the dynamic characterization of composite materials and the demonstrators within the framework of the BEDYN project will be briefly described. This work has received funding from the Clean Sky 2 Joint Undertaking (JU) under grant agreement No. 886519. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and the Clean Sky 2 JU members other than the Union.