Determination of the minimum distance between vibration source and fibre under existing optical vibration signals: a study

The article analyses why colleges and universities should strengthen innovation and entrepreneurship education based on ‘mass entrepreneurship and innovation.’ First, we conduct a questionnaire survey on the status quo of college students’ innovation and entrepreneurship and use nonlinear methods to construct an evaluation model of innovation and entrepreneurship capabilities to evaluate students’ innovation and entrepreneurship capabilities quantitatively. Finally, we verify the effectiveness of the combined evaluation model through the data on the innovation and entrepreneurship of college students. The research results can provide a new idea for appraisal of college students’ innovation and entrepreneurship ability.

Performance of Optical Structural Vibration Monitoring Systems in Experimental Modal Analysis

Image-based optical vibration measurement is an attractive alternative to the conventional measurement of structural dynamics predominantly relying on accelerometry. Although various optical vibration monitoring systems are now readily available, their performance is currently not well defined, especially in the context of experimental modal analysis. To this end, this study provides some of the first evidence of the capability of optical vibration monitoring systems in modal identification using input–output measurements. A comparative study is conducted on a scaled model of a 3D building frame set in a laboratory environment. The dynamic response of the model to an impulse excitation from an instrumented hammer, and an initial displacement, is measured by means of five optical motion capture systems. These include commercial and open-source systems based on laser Doppler velocimetry, fiducial markers and marker-less pattern recognition. The performance of these systems is analysed against the data obtained with a set of high-precision accelerometers. It is shown that the modal parameters identified from each system are not always equivalent, and that each system has limitations inherent to its design. Informed by these findings, a guidance for the deployment of the considered optical motion capture systems is given, aiding in their choice and implementation for structural vibration monitoring.