Study on Interlaminar Shear Strength Test Method of Fiber Reinforced Organic Composite Materials

Abstract

Fiber reinforced organic composites materials such as GFRP, which consist of glass fiber and epoxy resin, are intended for use as insulating and structural materials for superconducting magnets. In order to maintain the reliability and long-term durability of these insulating materials, the adhesive strength between laminates, or between laminates and the inserted films are important. In the composites, the adhesive strength is defined as the interlaminar shear strength and is one of the most important index of the composites materials. In this experiment, the test was conducted to establish a method to evaluate the interlaminar shear strength of thin-FRP. The shear test method specified by JIS and ASTM does not produce pure shear failure in fiber reinforced plastics, especially thin composites, and it is difficult to obtain accurate interlaminar shear strength. We developed the shear test method where the interlaminar shear strength can be accurately measured using NAL method and notched specimen from different surface. The experiments were performed both at room and nitrogen temperature. Obtained data were compared with those in ASTM method. It was confirmed that the developed method showed satisfactory performance to obtain the interlaminar shear strength.