Full Strain Field Determination with Rigorously Derived Quality Assessment
Date Issued
2014
Date
2014
Author(s)
Guo, Jenny
Abstract
Structural health monitoring is an ongoing issue. Knowing the state of strain can help to evaluate a structure’s health status by employing strain failure criteria. In this study, a full strain field determination based on the non-iterative solution for linear transformations (NISLT) technique is developed with a main emphasis of identifying rigid-body motion and natural deformation coupled in the displacement fields. Furthermore, an analytical expression of the covariance matrix of the linear transformation parameters determined from the NISLT approach is rigorously derived. By attaining the quality of the displacement field, one can assess the quality of the determined strain parameters. The derivation was verified in numerical simulations and in various types and scales of laboratory experiments which demonstrated that the estimated strain fields differ from the originally assumed principal strain (real strain) or the strain gauge reading within the range of 1.96 times the standard deviation. The derived quality assessment of the NISLT approach provides a fair estimation of how accurate the strain would be under certain observation noise while the corresponding rigid body motion could be explicitly identified. Thereby, the quality of a structural health monitoring system under strain failure criteria could be properly regulated, which is important for the planning of structural monitoring tasks.
Subjects
應變場估計
剛體運動
自然變形
非迭代線性轉換
誤差傳播
品質評估
Type
thesis
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