Abstract Sheet molding compounds (SMCs) are becoming key materials for the current and future transportation industry due to their outstanding mechanical properties, low density and easy processability. To meet the high standards required by the mentioned industry, robust mechanical characterizations of the materials must be carried out. In the case of SMCs, the use of testing geometries which can capture their heterogeneous microstructure and the effects of their 25 mm long fiber bundle reinforcements, turns out to be necessary. Driven by this demand, in this work, a novel coupon geometry for tensile characterization of a SMC material has been designed and validated. The new design concept has been developed based on three main features: (a) a central area of 30x49 mm2 for assuring a suitable representative volume element (RVE) of the material’s microstructure, (b) reduced cross section in the central area for localizing stresses and promoting the coupon failure within the RVE and (c) a reduced total length of 115 mm for material saving during characterization campaigns. Besides, the tensile tests demonstrate the validity of the novel coupon geometry through the obtention of results in accordance with those captured with standard coupons used in material datasheets.

中文翻译：

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用于片状模塑料拉伸性能测定的新型试样几何形状

摘要 片状模塑料 (SMC) 由于其出色的机械性能、低密度和易加工性，正成为当前和未来交通运输行业的关键材料。为了满足上述行业要求的高标准，必须对材料进行可靠的机械表征。在 SMC 的情况下，使用测试几何形状可以捕获其异质微观结构及其 25 毫米长纤维束增强的影响，结果证明是必要的。在这一需求的推动下，在这项工作中，设计并验证了一种用于 SMC 材料拉伸表征的新型试样几何形状。新的设计理念基于三个主要特点：(a) 30x49 mm2 的中心区域，用于确保材料微观结构具有合适的代表性体积元素 (RVE)，(b) 减小中心区域的横截面，用于局部应力并促进 RVE 内的试样失效，以及 (c) a减少了 115 毫米的总长度，以在表征活动期间节省材料。此外，拉伸测试通过获得与材料数据表中使用的标准试样捕获的结果一致的结果，证明了新型试样几何形状的有效性。