Model Updating Using Measurements from Sensors Installed in Arbitrary Positions and Directions

Abstract

The present study proposes a method for model updating using measurements from sensors installed in arbitrary positions and directions. Modal identification provides mode shapes for physical quantities (acceleration strain, etc.) measured in specific directions at the location of the sensors. Besides, model updating involves the use of the mode shapes related to the nodal degrees-of-freedom of the finite element analytic model. Consequently, the mode shapes obtained by modal identification and the mode shapes of the model updating process do not coincide even for the same mode. Therefore, a method for constructing transform matrices that distinguish the cases where measurement is done by acceleration, velocity, and displacement sensors and the case where measurement is done by strain sensors was proposed to remedy such disagreement among the mode shapes. The so-constructed transform matrices were then applied when the mode shape residual was used as the objective function or for mode pairing in the model updating process. The feasibility of the proposed approach was verified by means of a numerical example in which the strain or acceleration of a simple beam was measured and a numerical example in which the strain of a bridge was measured. Using the proposed approach, it was possible to model the structure regardless of the position of the sensors and to select the location of the sensors independently from the model.

Two-Step Calibration Method for Inverse Finite Element with Small Sample Features

“…The calibration results of the first and second elements are shown in Tables 4 and 5, respectively. In the The working conditions (9)(10)(11)(12)(13)(14)(15)(16) in Table 3 were used to verify the calibration accuracy of the trained SSFN. Inputting the measured strain into the trained SSFN, the kinematic variables after the second step calibration could be obtained.…”

“…In practical engineering, the installation position of the sensor greatly affects the reconstruction accuracy. In [ 13 ], a model update method was proposed based on the measured values of sensors installed at arbitrary positions and orientations. This method can establish the model independently, regardless of the position of the sensor, but it requires more model information.…”