Utjecaj smjera opterećivanja na mehanička svojstva plastomernih kompozita jednoosno ojačanih ugljičnim vlaknima

master's thesis

• Title (english): Effect of load direction on the mechanical properties of uniaxially reinforced thermoplastic based composites
• Author: Vanja Perić
• Mentor: Tatjana Haramina (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2019-12-05, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Zbog mogućnosti krojenja svojstava, ubrzavanja proizvodnje i male gustoće, kompoziti s plastomernom matricom su sve zastupljeniji na tržištu. Neki plastomeri imaju sposobnost samoobnavljanja. Samoobnavljanje lakih kompozitnih konstrukcija posebno je atraktivno u zrakoplovnoj tehnici. Numerički modeli koji opisuju ponašanje materijala ponekad su dobra alternativa eksperimentu, a kvaliteta modela provjerava se uz pomoć eksperimentalnih ispitivanja realnih sustava. Za potrebe modela, napravljeni su kompoziti od samoobnovljive plastomerne matrice Surlyna 8940 ojačane jednousmjerenim ugljičnim vlaknima te su istražena savojna i rastezna svojstva epruveta izrezanih pod 0°, 45° i 90° u odnosu na smjer vlakana. Rezultati ispitivanja pokazuju da ugljična vlakna značajno poboljšavaju mehanička svojstva matrice u svim smjerovima opterećivanja, pri čemu je najbolji učinak vidljiv pri rasteznom opterećenju u smjeru vlakana, gdje je modul porastao 16,5 puta, a rastezna čvrstoća 6 puta. Osim savojnog i rasteznog ispitivanja, provedeno je i jednoosno cikličko opterećenje na kidalici s ciljem provjere primjenjivosti u literaturi dostupnih modela za samoobnovljive materijale na Surlyn 8940. Dobivena histereza potvrđuje primjenjivost modela.

Abstract (english)

The ability to tailor properties, faster production cycles and low density, make composites with thermoplastic matrix increasingly present on the market. Some thermoplastic materials have the capability of self-healing. Self-healing of lightweight composite designs is particularly attractive in aeronautical engineering. Numerical models describing the behavior of materials are sometimes a good alternative to experiment. The quality of a numerical model must be verified by means of experimental testing of real systems. In order to develope a numerical model for composites based on a self-healing thermoplastic matrix that is reinforced with unidirectional carbon fibers bending and tensile properties of samples cut at 0°, 45° and 90°, with respect to the fiber direction, were investigated. The test results show that carbon fibres significantly improve the mechanical properties of the matrix in all stress directions. The best effect is observed under tension in the fiber direction (0°), where the modulus increased 16,5 times, and the tensile strength 6 times. In addition to flexural and tensile testing, a uniaxial cyclic experiment was carried out in order to test the applicability of the models for self-healing materials avaliable in the literature to the matrix material. The hysteresis obtained confirms the applicability of the model.

• Keywords: plastomerni kompoziti; E/MAA; ugljična vlakna; jednosmjerno ojačanje; rastezna svojstva; savojna svojstva; cikličko opterećenje
• Keywords (english): thermoplastic composites; E/MAA; carbon fibers; unidirectional reinforcement; tensile properties; bending properties; cyclic load
• Language: croatian
• URN:NBN: urn:nbn:hr:235:818507
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-11-28 08:43:31