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The availability of materials data for impact-mitigating materials has lagged behind applications-based data. For example, data describing on-field helmeted impacts are available, whereas material behaviors for the constituent impact-mitigating materials used in helmet designs lack open datasets. Here, we describe a new FAIR (findable, accessible, interoperable, reusable) data framework with structural and mechanical response data for one example elastic impact protection foam. The continuum-scale behavior of foams emerges from the interplay of polymer properties, internal gas, and geometric structure. This behavior is rate and temperature sensitive, therefore, describing structure-property characteristics requires data collected across several types of instruments. Data included are from structure imaging via micro-computed tomography, finite deformation mechanical measurements from universal test systems with full-field displacement and strain, and visco-thermo-elastic properties from dynamic mechanical analysis. These data facilitate modeling and design efforts in foam mechanics, e.g., homogenization, direct numerical simulation, or phenomenological fitting. The data framework is implemented using data services and software from the Materials Data Facility of the Center for Hierarchical Materials Design. [ABSTRACT FROM AUTHOR]

Double-Sided Incremental Forming (DSIF) uses two small, independently moving, hemispherical tools on either side of the sheet to form a desired shape by following a predefined tool path. This study was motivated by the observation that the relative tool position of the tools, specified in the tool path generation algorithm, affects the formed geometric accuracy. A methodology for defining the relative tool positioning in the tool path generation algorithm based on local part geometry is proposed using simplified Finite Element Analysis (FEA) and sample physical experiments combined with Gaussian Process modeling techniques. This approach can take into account the mechanics of deformation in DSIF explicitly and physical compliance of the DSIF machine implicitly. Physical experiments were performed to demonstrate the effectiveness of the proposed framework. [ABSTRACT FROM AUTHOR]

The temperature above which neither stress nor plastic strain can cause austenite to transform to martensite is determined for 304 austenitic stainless steel by X-ray diffraction measurements on specimens that were previously subjected to isothermal tension tests. The specimens were tested at 273 K, 298 K, 308 K, 333 K, and 373 K (0 °C, 25 °C, 35 °C, 60 °C, and 100 °C). A new isothermal testing technique was used not only for controlling the testing temperature but also for averting deformation-induced heating. Hence, the effect of temperature on the strain-induced martensite is decoupled from that of strain. The diffraction measurements reveal that the martensite volume fraction decreases linearly with the testing temperature up to a critical temperature, which is found by linearly extrapolating to zero martensite volume fraction. [ABSTRACT FROM AUTHOR]