Karakterizacija kompleksnega modula elastičnosti viskoelastičnega materiala na podlagi dinamskega odziva plošče

magistrsko delo magistrskega študijskega programa II. stopnje Strojništvo

Andraž Kladnik (Author), Miha Boltežar (Mentor), Martin Česnik (Co-mentor)

Abstract

Pogostost uporabe polimernih materialov v zahtevnih inženirskih aplikacijah se povečuje z boljšim razumevanjem njihovih temperaturno in časovno odvisnih materialnih lastnosti. Dinamske lastnosti polimerov popisuje kompleksni modul, ki se ga določi z metodo dinamske mehanske analize DMA (ang. Dynamic Mechanical Analysis). Glavna pomanjkljivost te analize je način vpetja vzorca, saj je togost vpetja odvisna od temperature, pri kateri se izvaja meritev. V sklopu magistrskega dela je bil zasnovan nov postopek določanja dinamskih lastnosti, pri katerem je vzorec prosto vpet. Vzorec predstavlja plošča, ki jo dinamsko vzbujamo brezkontaktno preko permanentnega magneta in tuljave, njen odziv pa merimo z laserskim vibrometrom. Na podlagi frekvenčnih prenosnih funkcij nato preko ekvivalentnega numeričnega modela s posodabljanjem določimo kompleksni modul. Meritve so bile opravljene pri več temperaturah. Rezultati nove metode so primerljivi z rezultati DMA analize.

Keywords

magistrske naloge;dinamske lastnosti polimerov;dinamika plošče;elektromagnetno vzbujanje;brezkontaktno merjenje;frekvenčna odvisnost;temperaturna odvisnost;

Data

Language:	Slovenian
Year of publishing:	2021
Typology:	2.09 - Master's Thesis
Organization:	UL FS - Faculty of Mechanical Engineering
Publisher:	[A. Kladnik]
UDC:	539.32:678.7:537.8(043.2)
COBISS:	78071811
Views:	425
Downloads:	47
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Characterization of complex elasticity modulus of viscoelastic material based on the dynamic response of the plate
Secondary abstract:	The usage of polymer materials for demanding engineering applications is increasing due to better understanding of their temperature- and time-dependant properties. Dynamic properties of polymers known as complex modulus is measured with Dynamic Mechanical Analysis (DMA). The main disadvantage of this method is fixation of the sample, since its stiffness strongly depends on temperature during the measurement. The aim of this master thesis is development of new method for measurements of dynamic properties based on free-free supported sample. The sample is polyamide plate, which is dynamically excited with contactless method using interaction of permanent magnet secured to the plate and a coil. The response of the plate is measured with laser vibrometer. Parameters of measured frequency response functions are used as input parameters of equivalent numerical model. The complex modulus is determined by updating its value untill permissible error between measurement and numerical model is reached. The measurements were carried out at the different temperatures and the results are comparable to the one of standard DMA.
Secondary keywords:	master thesis;dynamic properties of polymers;dynamic response of plate;electromagnetic excitation;non-contact;non-contact measurement;frequency dependent;temperature dependent;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. Ljubljana, Fak. za strojništvo
Pages:	XXVI, 80 str.
ID:	13285841