ULTRASONIC C-SCAN INSPECTION OF RESIN TRANSFER MOLDED (RTM) COMPOSITE TUBES FOR VOID CONTENT DETERMINATION AND QUALITY CONTROL

摘要

Tubular structures fabricated from composite materials have found attractive uses in advanced fuselages, rocket motor cases, space truss structures, landing gear and launch tubes etc. The effective utilization of the structural properties of this materials is contingent on developing a non destructive method of evaluating their properties. The successful use of ultrasonic energy in non-destructive testing of composite materials, require an adequate knowledge of the principle of wave propagation and all the associated phenomena. These include the derivation and solutions of those equations that describe the propagation of sound waves in these materials. The composite tubes were fabricated using Resin Transfer Molding Technique (RTM) utilizing a single cylindrical mold and a Teflon rod mandrel. The void content of the composite tubes were determined using an ultrasonic C-scan equipped with a specially designed fixture. The fixture enabled the indexing of the X-axis stepper motor that inturn rotates the composite tube in unison to the scanning action of the ultrasonic C-scan transducer. The setup for the ultrasonic inspection is shown in Figure 1.rnThe result of the percentage of relative void content of the inspected composite tubes, range between 0.00 to 0.09 percent, which was within an acceptable range of good quality standard.