Effect of ply types and micro-Nano sio2 particles on interlaminar fracture toughness of epoxy reinforced by glass fiber composites

Other Title(s)

تأثير أنواع الطبقات و الجسيمات المايكروية-النانوية على متانة التكسر الطبقية لمتراكبات الايبوكسي المدعم بالألياف الزجاجية

Dissertant

al-Sabbagh, Zaynab Rahim Muslim

Thesis advisor

al-Shammari, Harith Ibrahim Jafar

University

University of Baghdad

Faculty

College of Science

Department

Department of Physics

University Country

Iraq

Degree

Ph.D.

Degree Date

2013

English Abstract

The effect of mid- plane layer, lay –up stacking sequence and the addition of micro and nano SiO2 particles on the interlaminar fracture toughness ,Young modulus and flexural strength for epoxy resin composites reinforced with glass fiber type woven roving mat or mat [M] and chopped strand mat or random [R] have been studied.

Specimens were prepared using hand-lay up technique arranged with respect to fibers orientation and with 16 plies .

Seven sets of specimens were prepared such as [M]16 , [R]16 [R7//M1/M1//R7] ،[M7//R1/R1//M7],[//M/R//]s,[M/R//M1/M1//R/M]S and [R/M//R1/R1//M/R]S.

Interlaminar fracture toughness GIC were measured using double cantilever beam (DCB) test for mode- I using area method, compliance method, compliance calibration method and modified beam theories.

The results showed that epoxy reinforced with random glass fiber has higher GIC (2834 J/m2) than that of epoxy reinforced with woven roving glass fiber (548 J/m2).

The results of different types of mid plane layers show that the Interlaminar fracture toughness GIC for [R7//M1/M1//R7]is (3018 J/m2) which is higher than that of [M7//R1/R1//M7] is(354 J/m2) .

It was shown also that lay – up stacking sequences have an effect on the Interlaminar fracture toughness GIC .

It was observed that GIC for [R/M//R1/R1//M/R]S is (1355 J/m2)which is higher than that [//M/R//]s is (260 J/m2) .

6 Traveling microscope was used to study the behavior of crack propagation.

Fiber bridging phenomena was seen in random composites and the composites with random glass fiber mid layer.

Fast and unstable crack propagation was seen in woven roving composites in comparison with random composites, which mean that random composites have high resistance for crack propagation.

Nano and micro SiO2 particles were used as a third phase filler for woven roving glass fiber composites with (2,4,6,8,10) wt % .

It was found that higher GIC was observed for nanocomposites as compared with microcomposites ,because nano SiO2 behave as a barrier for crack propagation and the large surface density of these nanoparticles take a position in the polymeric chain restricting the movement for these chains leading to higher values of GIC in comparison with micro SiO2 .The lower value of GIC found in 6 and 8 wt% because of the agglomeration of nano particles , this reflects the behavior of laminated nanocomposites into the same as microcomposites.

Young modulus and flexural strength were measured using transverse loading.

The specimens were cut along the y-direction to study the effect of mid –plane layer on crack propagation and behavior using 3- point bending test .

Higher flexural strength was found for [M]16 .

The results shows that Young modulus for nanocomposites was higher than microcomposites , but flexural strength for microcomposites was higher.

Main Subjects

Physics

No. of Pages

155

Table of Contents

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Language

English

Data Type

Arab Theses

Record ID

BIM-608152