Background

For the static loading test in the aerospace field, conventional strain field reconstruction methods relying on finite element analysis (FEA) or test data are difficult to meet the accuracy requirements of test monitoring.

Objective

This study aims to construct a high-accuracy strain field for real-time test monitoring.

Methods

An improved strain field reconstruction method based on digital twin (DT) named as DT-SFRM is proposed. The DT is built by data fusion of FEA results and test data, which combines the benefits of these data. The FEA conducted before formal test provides approximate strain field distribution, and the strain gauges data with high accuracy are used to modify FEA strain fields in real time. After that, the real-time DT is used to determine the possible risk regions of test articles. Finally, a large opening cylindrical shell (LOCS) buckling test is conducted to validate the advantages of DT-SFRM.

Results

Results show that the accuracy of DT-SFRM is much higher and less affected by the nonlinearity of test data than that of conventional methods. Compared with the time cost by conventional real-time FEA (about 50 min), the DT method only takes 9s to reconstruct strain field, and the possible risk regions predicted by DT-SFRM are more consistent with test buckling regions of LOCS than conventional methods.

Conclusions

The DT-SFRM is validated to have a higher accuracy and better monitoring effect, and it is more suitable for test monitoring of complex structures.

中文翻译：

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一种改进的基于数字孪生的测试监控应变场重建方法

背景

对于航空航天领域的静载试验，传统的依靠有限元分析（FEA）或试验数据的应变场重建方法难以满足试验监测的精度要求。

客观的

本研究旨在构建用于实时测试监测的高精度应变场。

方法

提出了一种基于数字孪生（DT）的改进应变场重建方法DT-SFRM。DT是通过FEA结果和测试数据的数据融合构建的，它结合了这些数据的优点。正式试验前进行的有限元分析提供了近似的应变场分布，并利用高精度的应变片数据实时修正有限元分析应变场。之后，利用实时DT来确定测试品可能存在的风险区域。最后，进行了大开口圆柱壳（LOCS）屈曲试验，验证了DT-SFRM的优势。

结果

结果表明，与传统方法相比，DT-SFRM的精度要高得多，并且受测试数据非线性的影响更小。与传统实时有限元分析的时间成本（约50分钟）相比，DT方法仅需9秒即可重建应变场，并且DT-SFRM预测的可能风险区域与LOCS的测试屈曲区域比传统方法更加一致。

结论

经验证，DT-SFRM具有更高的精度和更好的监测效果，更适合复杂结构的试验监测。