Viscoelastic behavior of filled elastomeric materials under cyclic loading

مقدم أطروحة جامعية

al-Abbadi, Asya Abd al-Sattar R.

مشرف أطروحة جامعية

Hamzah, Muhsin Nuri

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم الهندسة الميكانيكية

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2012

الملخص الإنجليزي

The mechanical behavior of filled elastomeric materials is known to be incompressible, or nearly-incompressible, hyperelastic and time-dependent, or viscoelastic.

This complex behavior of rubbery materials needs more understanding,and a good knowledge is required for such behavior in order toattain a constitutive modeling for better designof a rubber component for a specific application.

To do this, different tests were performed on filled rubber in the present thesis.

The experimental work consists of tensile tests, hardness tests, compression set tests, specific density tests, relaxation tests, and cyclic loading.

All tests were performed on filled rubber materialwith three different kinds of carbon black (N326, N375, and N660)at room temperature.

The work concentrated on studying the effect of different kinds of carbon black on the materialcharacterizationlike stiffness, strength, density, viscoelastic and Mullin effect (softening).

Tensile tests and cyclic loading testes were done with differentspeed test, relaxation tests were done with different mean strain.

Tensile stress-stretch curves were generated from the test data at speed tests ranging from 10 to 500 mm/min, andseveral transitions associated with the strain-induced crystallization were observed in all materials.

The filled rubber became stiffer when the speed test increased from 10-200 mm/min, and it became more compliant when the speed test increased from 200 to 500 mm/min.

Hardness and specific density tests showed that the rubber filled with carbon black N375is harder and has a specific density more than other two types of filled rubber.

The mechanical compression set tests,were performed on rubber with three kinds of carbon black and it was found thatthe compression set for rubber filled with carbon black (N375) ismore than the other two kinds of filled rubber.

Relaxation stress-timecurveswere generated from the test data at varying mean strainrange (50% to 200%) from the effective length of the specimen, at constant speed test (200 mm/min).

Generally,it was observed that the stress decreased with time when the specimen was held at specific strain.This reduction is faster at strain between 50% and 100% than thestrain between 150 to 200%till it reaches steady state.

Series of cyclic tension tests were carried out at room temperature on a rubber compound under speed tests ranging from 10 to 500 mm/min.Allthese cyclic strain-controlled experiments showed that the filled rubber materials, used in the present work,are time-dependentwithhysteresis.It was found out that the hysteresis for rubber with carbon black (N375) is more than the rubber with other two kinds of carbon black.

Theoretical work is considered for modeling the hyperelastic and viscoelastic behaviors of rubber.

The hyperelastic behavior is modeled using Mooney–Rivlin constitutive model.

While the time-dependent behavior (viscoelasticity) was modeled by using Prony series.

Modeling and parameters identification, for both hyperelastic and viscoelastic behaviors, were performed and compared with ANSYS 14.0.

التخصصات الرئيسية

الهندسة الميكانيكية

الموضوعات

• البوليمرات المرنة

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-419847