Volume 10, Issue 3 (May 1982)
A Microcomputer-Based System for Instrumented Impact Testing
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.