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The measurement accuracy of instrumented ship structures under local loads using strain gauges
Citation Link: https://doi.org/10.15480/882.3182
Publikationstyp
Master Thesis
Date Issued
2019
Sprache
English
Author(s)
Advisor
Title Granting Institution
Technische Universität Hamburg
Place of Title Granting Institution
Hamburg
Examination Date
2019-04-04
TORE-DOI
TORE-URI
The State of the Art measurement set up for ice loads measurements is as follows. On four to five frames there are strain gauges attached on each end for measurements of shearstrain differences. With the help of a finite element analysis (FEA) the load strain relation of the instrumented section can be determined. This load strain relation is displayed in the so-called influence coefficient matrix which is obtained by the unit load principle. Nevertheless after the many past measurements the following questions arise. How accurate is the mapping of the influence coefficient matrix? Which structures are suitable for measurements of shear-strain differences? How can the existing method be improved and what measurement uncertainties are inherent in the overall system? In order to achieve the goal of this work, the theory of shear-strain measurement was presented. In addition to shear-strain measurement, the theory of shear-strain measurement on ships for the determination of ice loads was explained. Besides a grillage model which consists of five frames and one plate was modeled and point loads and pressures were investigated by finite element analysis. Under the given conditions symmetrical structures with a good load alignment are suitable for measurements of shear-strain differences. Besides, the author shows how the influence coefficient matrix maps the response of the structure. The best mapping of the influence coefficient matrix could be achieved with a double instrumentation of the frames. The location of the load, the load length and the pressure distribution within the contact area were one of the biggest uncertainties. The author shows how the already existing measurement system can determine loads in the middle of the frames. In
addition an approach to estimate the load length is presented as well. At the end there is a recommendation for further investigations of this kind.
addition an approach to estimate the load length is presented as well. At the end there is a recommendation for further investigations of this kind.
Subjects
Ice loads
Influence coefficient matrix
Accuracy
Load location
Load length
DDC Class
600: Technik
620: Ingenieurwissenschaften
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21266467_Angelo Boehm - Master Thesis.pdf
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