Study of methods for measuring torque and strains on shafts made of composite materials

Μαυροζούμης, Θεόδωρος; Mavrozoumis, Theodoros

dc.contributor.author	Μαυροζούμης, Θεόδωρος
dc.contributor.author	Mavrozoumis, Theodoros	en
dc.date.accessioned	2023-03-27T07:56:18Z
dc.date.available	2023-03-27T07:56:18Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/57318
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.25016
dc.rights	Default License
dc.subject	Σύνθετα Υλικά	el
dc.subject	Άξονες	el
dc.subject	Ροπή	el
dc.subject	Παραμορφώσεις	el
dc.subject	Composite Materials	en
dc.subject	Shafts	el
dc.subject	Torque	el
dc.subject	Strains	el
dc.subject	Μετρήσεις	el
dc.subject	Measurements	el
dc.title	Study of methods for measuring torque and strains on shafts made of composite materials	en
dc.title	Μελέτη μεθόδων μέτρησης ροπής και παραμορφώσεων σε άξονες από σύνθετα υλικά	el
heal.type	bachelorThesis
heal.classification	Measurements	en
heal.classification	Composite Materials	en
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2023-02-20
heal.abstract	Nowadays, composite materials are widely used in a variety of applications in marine and automotive industries, aerospace, aircrafts, buildings, and sport equipment. Low weight and high strength are the most predominant features of such materials which makes them a favorable option for even wider use is many structures. Composite shafts, mainly carbon fiber reinforced polymer, are a characteristic case where such materials have started to be used and research for their development is steadily increasing. Especially in the marine sector, composite driveshafts can also offer corrosion resistance, low bearing loads, reduced magnetic signature and higher fatigue resistance among other advantages. For driveshafts torque monitoring during operation is an essential need for measuring the power transmitted to the propeller or for performance evaluation and process monitoring and control of combustion engines or electric motors. Another aspect is the strain measurement of shafts, or in general of other composite cylindrical structures (e.g. pipes, tubes), for stress analysis which is related to Structural Health Monitoring. The main aim of this thesis, therefore, is an overview of the methods that are used for torque and strain measurements on such structures. In the context of this thesis methods that are commonly used in commercial applications or other that are still in a more preliminary - laboratory level are presented. Based on the technique and/or the sensors that are used, a first categorization was made. Strain Gauges (SG) are the most widely used system for strain measurement and many commercially available torque transducers are based on this technique. For the connection between the rotating shaft and the stationary part of the measurement system contact connection with slip rings or non-contact connection with either inductive power supply and/or signal transmission or with wireless RF telemetry can be made. On composite shafts due to their orthotropic behavior, SG are more difficult to be used and more aspects are needed to be taken into account. Fiber Optic Sensors (FOS) are also under development for both SHM and torque measurement but still in a laboratory level. Fiber Optic Rotary Joints (FORJ) and other systems which use special lenses (Graded-Index or C-lenses) can be used for non-contact signal transmission although the problem ingress/egress point of such systems on rotating driveshaft is still unsolved. Twist angle measurement is also widely used in commercial off-the-selves systems as it offers simultaneously speed measurement and can be mounted on already existing shafting systems without disassembly. Lastly, other systems which utilize Surface Acoustic Waves (SAW), Digital Image Correlation (DIC) or other techniques that are under development were also found. A static torsional test on a CFRP shaft was conducted in the Laboratory of Testing and Materials (LTM) of the School of Applied Mathematics and Physical Science of NTUA in Athens in order to check the validity of the TorqueTrak 10k torque meter from Binsfeld which is based on the wireless RF telemetry signal transmission technique. For that reason, analytical estimation of equivalent mechanical properties of the shaft was made and a split-disk test in ring-shaped specimens for the experimental calculation of the Young’s modulus in the hoop direction. Although many problems were encountered in both experimental procedures, some useful conclusions about the applicability of this torque meter on composite shafts could be drawn after processing the results. Finally, FEM analysis in ANSYS simulation program was conducted. Deviation between the numerical and experimental torsional stiffness was observed. This is probably attributed to the overestimation of material mechanical properties considered for the modelling of the shaft (mainly E1) and some deviations in the geometry (thickness, exact orientation of layers). Lastly, since the maximum torque achieved during the torsional test was much lower than the critical buckling torque of the shaft obtained from FEM and analytical solutions, no safe estimation of the torsional buckling modeshape could be made.	el
heal.advisorName	Τσούβαλης, Νικόλαος	el
heal.committeeMemberName	Παπαδάκης, Γεώργιος	el
heal.committeeMemberName	Σαμουηλίδης, Μανόλης	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Θαλάσσιων Κατασκευών. Εργαστήριο Ναυπηγικής Τεχνολογίας	el
heal.academicPublisherID	ntua
heal.numberOfPages	179 σ.	el
heal.fullTextAvailability	false