Biaxial testing of high strength carbon fiber composite cylinders for pulsed magnet reinforcement

A methodology is introduced to test carbon-fiber-reinforced, hoop-wound com posite cylinders for their biaxial mechanical properties under axial compre ssion and hoop tension. The understanding of the behavior of these composit es under biaxial loads is extremely important in the design of pulsed magne ts. These composites are used as reinforcements for both the inner conducti ng layers and as an overall exterior reinforcement. Testing of actual pulse d magnets to ascertain design change effects of composite reinforcement sch emes on the maximum attainable field can be expensive; hence, a standard bi axial testing method is desirable which is relevant to the design of pulsed magnets. In this investigation, an attempt was made to produce a standard testing procedure aimed at measuring the biaxial mechanical properties (ela stic, plastic, and failure envelope) of composite materials. This methodolo gy was applied to two different carbon/epoxy based composites. The results of these tests (elastic properties and failure points) are compared with th eoretical predictions, specifically those due to Tsai-Wu. (C) 1998 Publishe d by Elsevier Science Ltd. All rights reserved.