Abstract Conventional model updating methods are based on frequency response function (FRF) and/or modal parameter estimates obtained from freely suspended, or sometimes rigidly constrained, sub-structures. These idealised boundary conditions are however often difficult to realise in a practical scenario. Furthermore, they are in conflict with the requirement that the sub-structure should also be measured whilst under a representative mounting condition. This paper addresses the question whether model updating can be achieved in the presence of an arbitrary or unknown boundary condition using in-situ measurements, i.e. without removing the sub-structure from its assembly. It is shown that some measurable properties, dynamic transfer stiffness and generalised transmissibility, are invariant to sub-structural boundary conditions and can therefore be obtained in-situ. It is further shown that, with minor adaption, existing transmissibility-based updating methods can be applied more widely than previously thought; to sub-structures whose boundary conditions are non-ideal. The theory is verified by a numerical beam example. Application to a resilient isolator is then demonstrated where a finite element model is successfully updated without removing the isolator from its assembly.

中文翻译：

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使用原位实验数据更新有限元模型

摘要 传统的模型更新方法基于频率响应函数 (FRF) 和/或从自由悬挂或有时严格约束的子结构中获得的模态参数估计。然而，这些理想化的边界条件在实际场景中通常难以实现。此外，它们与在代表性安装条件下也应测量子结构的要求相冲突。本文解决了在存在任意或未知边界条件的情况下是否可以使用原位测量实现模型更新的问题，即无需从其组件中移除子结构。结果表明，一些可测量的特性、动态传递刚度和广义传递性，对子结构边界条件是不变的，因此可以原位获得。进一步表明，通过较小的调整，现有的基于传递性的更新方法可以比以前认为的更广泛地应用；到边界条件不理想的子结构。该理论通过数值梁示例得到验证。然后演示了对弹性隔振器的应用，其中成功更新了有限元模型，而无需从其组件中移除隔振器。