1、 Copyright by International OCSCO World Press.All rights reserved.2007VOLUME 20ISSUES 1-2January-February2007Short paper203of Achievements in Materialsand Manufacturing Engineeringof Achievements in Materialsand Manufacturing EngineeringUltrasonic methods in diagnostics of glass-polyester composites
2、G.Wrbel,.Wierzbicki*Department for Processing of Metals and Polymers of the Institute of Engineering Materials and Biomaterials,Faculty of Mechanical Engineering,Silesian University of Technology,ul.Konarskiego 18a,44-100 Gliwice,Poland*Corresponding author:E-mail address:lukasz.wierzbickipolsl.plRe
3、ceived 30.10.2006;accepted in revised form 15.11.2006MaterialsAbstrActPurpose:The aim of the work was to find relationship between the ultrasonic wave velocity and the strenght and Youngs module in a glass-polyester composite.Design/methodology/approach:The experiments have been performed in three d
4、istinct phases.During the first phase,typical glass-polyester composite was ageing to get different mechanical properties.In the second phase,strength and ultrasonic properties of composite was testing.In the last of phases we compare changes of properties.Findings:The experimental results showed re
5、lationship between velocity of ultrasonic wave and strength and Youngs module.Research limitations/implications:In those applications,in which polymer structural composites were subjected to a heat and mechanical load,it is essential to test the strength characteristics of the composites in the use
6、of non-destructive methods.That enables contemporaneous status check of the structure and makes it possible to replace the bivalent evaluation scale(good bad)with an incessantly gradable strength degradation scale for a material.Practical implications:The results of the investigation have shown poss
7、ibility of using ultrasonic method to diagnosis of strength changes in composites.This method allowed to test working parts of machines or buildings,without destruction.Originality/value:The results of the investigations allow to confirm,that ultrasonics can be used to non-destructive testing of the
8、 strength and Youngs modulus changes.Keywords:Composites;Engineering polymers;Properties;Non-destructive testing1.Introduction Fiber-reinforced composites are being increasingly used as alternatives for conventional materials primarily because of their high specific strength,specific stiffness and t
9、ailorable properties.In addition the viscoelastic character of composites render them suitable for high performance structural applications like aerospace,marine,automobile,etc.However,these materials are quite distinct from metals because the former exhibit several peculiar modes of failure(matrix
10、crazing,delamination,fiber failure and interfacial bond failure due to debonding)and interaction at micromechanical 1,2.Nondestructive testing methods are one of the most dynamically developing branches of diagnosis and science in general.In those applications,in which polymer structural composites
11、are subject to a heat and mechanical load,it is essential to test the strength characteristics of the composites in use with non-destructive methods.That enables contemporaneous status check of the structure and makes it possible to replace the bivalent evaluation scale(good bad)with an incessantly
12、gradable strength degradation scale for a material 3.Based on the measurement of velocity and absorption coefficient of ultrasonic waves propagated in the sample volume,volumetric wave acoustics methods allow to acquire a variety of 1.IntroductionShort paper204Journal of Achievements in Materials an
13、d Manufacturing EngineeringG.Wrbel,.WierzbickiVolume 20 Issues 1-2 January-February 2007data concerning the structure of the substance.Velocity and absorption coefficient of ultrasonic waves in a solid body depend on mutual interactions of atoms,molecules or groups of molecules.Virtually every chang
14、e in the structure of matter causes a change in the interaction amongst vibrating oscillators,which is followed by a change in ultrasonic wave propagation parameters.Apart from microstructural changes,the acoustic characteristics of a material can also be influenced by degradation being a result of
15、accumulated microdamages caused by working conditions put on the structure 3.Description of the issue of microdamages accumulation process in composite materials creates a basis for efficiency of ultrasonic diagnostics in the load capacity wear evaluation process of a composite material.This paper i
16、s an attempt to determine dependencies between the degree of load capacity degradation and the changes in characteristic of an ultrasonic wave passing through an glass-polyester composite.1.1 Ultrasonic tests on composites The procedure of ultrasonic tests on objects comprises passing waves into objects,scanning objects by moving a head over their surface and detecting signals(impulses)caused by waves passed through objects.The basic rule in such tests is to know dependencies between the value o
