Part-to-part variability assessment of material properties for flat thin orthotropic rectangular panels using Chladni patterns

摘要

The material properties of orthotropic panels may be affected by the manufacturing variability because of the production processes used. This manufacturing variability can considerably modify the dynamic performance of these panels and consequently the one of the built-up structures. Therefore, it is important to quantify the material manufacturing variability across a batch of manufactured panels for quality control purposes and for the improvement of models of the built-up structure. Standard testing methods which are appropriate for testing a single component cannot be readily used for assessing material manufacturing variability. A simple yet effective inverse procedure based on the Chladni patterns is proposed to assess the material manufacturing variability of flat thin orthotropic rectangular panels. A detailed derivation of the equations needed for establishing the elastic constants of the panels is presented and used for the initial estimates of the materials properties. Moreover, an enhanced mathematical model is used to improve the initial estimate of the material properties using an iterative optimization procedure. A simple and relatively inexpensive setup is used. The repeatability and reproducibility of the results obtained with the Chladni setup are compared to the part-to-part variability results to assess the acceptability of the system to measure variability in the elastic constants of flat thin orthotropic rectangular panels. The Chladni setup is used to investigate three sets of nominal identical batches of thin panels: plywood, aluminium and FR4. It is shown that the Chladni setup is adequate to measure all four elastic constants for the three studied materials. Limitations, and quantification of the errors associated with the experiments and mathematical models are discussed. It is found that the accuracy of the results obtained can be improved by training the operator performing the experiment.