Abstract
The bending testing methods for advanced composite materials have not yet been authorized internationally. The 3-point and 4-point bending methods are not adequate because of local fracture due to stress concentration just beneath the loading points. In the present paper, the three kinds of zig were developed for trial, which could apply the uniform pure bending moment without shear force through the span. Three are, (1) Sliding Frame (SF) type, (2) Rack & Pinion (RP1) type and (3) Rack & Pinion (RP2) type. Both SF and RPl types have the disadvantages to need corrections for the flexural strength and deflection due to the changes of reaction direction or span length, respectively. However, specimens used in experiments using RP2 broke into pieces under axial stress in the fiber direction between both tabs without stress concentration. Flexural strength values under pure bending were more than 30%-50% higher than those under 3-point and 4-point bending methods.
