The validation of numerical models requires the comparison between numerical and experimental results, which has led to the development of benchmark tests in order to achieve a wider participation. In the sheet metal-forming research field, the benchmarks proposed by the Numisheet conference series are a reference, because they always represented a challenge for the numerical codes within the state of the art in the modeling of sheet metal forming. From the challenges proposed along the series of Numisheet benchmarks, the springback prediction has been frequently incorporated, and is still a motivation for the development and testing of accurate modeling strategies. In fact, springback prediction poses many challenges, because it is strongly influenced by numerical parameters such as the type, order, and integration scheme of the finite elements adopted, as well as the shape and size of the finite element mesh, in addition to the constitutive model. Moreover, its measurement also requires the definition of a fixture that should not influence the actual springback and the proper definition of the measurement locations and directions. This is the subject of this contribution, which analyzes the benchmark focused on springback prediction, proposed by the Numisheet 2016 committee. Numerical results are obtained with two different codes and comparisons are performed between both numerical and experimental data. The differences between numerical results are mainly dictated by the ambiguous definition of boundary conditions. The analysis of numerical and experimental springback results should rely on the use of global planes to ensure the objectivity and simplicity in the comparison. Therefore, the analysis gives an insight into issues related to the comparison of results in complex geometries involving springback, which in turn suggests some recommendations for similar future benchmarks.

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钣金成形基准试验与数值结果之间的相关性问题

数值模型的验证要求将数值结果与实验结果进行比较，这导致了基准测试的发展，以实现更广泛的参与。在钣金成形研究领域，Numisheet会议系列提出的基准是参考，因为它们始终代表着对钣金成形建模领域中现有技术中的数字代码的挑战。从Numisheet基准系列提出的挑战中，回弹预测已被频繁合并，并且仍然是开发和测试精确建模策略的动力。实际上，回弹预测会受到很多挑战，因为它会受到数值参数（例如类型，顺序，除本构模型外，还采用有限元的集成方案，以及有限元网格的形状和大小。此外，其测量还需要定义夹具，该夹具不应影响实际的回弹力以及对测量位置和方向的正确定义。这是此贡献的主题，它分析了由Numisheet 2016委员会提出的，针对回弹预测的基准。用两个不同的代码获得数值结果，并在数值和实验数据之间进行比较。数值结果之间的差异主要由边界条件的模糊定义所决定。数值和实验回弹结果的分析应依赖于全局平面的使用，以确保比较的客观性和简便性。因此，分析可以深入了解与涉及回弹的复杂几何形状中的结果比较相关的问题，从而为类似的未来基准提出了一些建议。