ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 6

A Microcomputer-Based System for Instrumented Impact Testing

Crawford, RJ
Lecturer and research fellow, Queen's University, Belfast,

McFerran, NV
Lecturer, Queen's University, Medical Biology Center, Belfast,

Ali, A
Lecturer and research fellow, Queen's University, Belfast,

Abstract

As part of a program of research to study the influence of processing conditions on the impact strength of injection moldings, a relatively inexpensive modification has been made to an Izod type impact test machine so that fully instrumented tension impact tests may be carried out. The principle of operation of the system is described in detail. Basically a quartz load cell in the base of the test machine sends the impact signal through a charge amplifier to a transient recorder. Having thus stored the signal, the data is passed to a microcomputer where it is transformed from force-time to force-deformation. The trace is integrated to provide the impact strength of the test sample. This value is then printed out along with characteristic details of the sample, including a graph showing the shape of the force-deformation relationship.

The main improvement this type of system offers over conventional single value impact testing lies in the convenience of use and increased amount of information available on the type of fracture that has occurred. This is supported by typical system printouts and photographs of fractured samples.

Keywords:
impact tests, impact strength, injection molding, instrumented impact tests, tension impact tests, plastic impact strength, high strain-rate tests, microcomputers, interfacing, materials testing, fracture

Paper ID: JTE10246J
DOI: 10.1520/JTE10246J
ASTM International is a member of CrossRef.