AN EVALUATION OF THE ARCAN SPECIMEN FOR DETERMINING THE SHEAR MODULI OF FIBER-REINFORCED COMPOSITES

Moire interferometry was used to examine the strain distributions in A rcan-type specimens under shear loading. The compact geometry allowed longitudinal and transverse shear behavior to be considered. The best results for longitudinal moduli were obtained with fibers running from notch to notch. As with the Iosipescu configuration, strain averaging or correction factors were required for modulus determination in all fiber orientations. None of the bending problems that have been encoun tered in the Iosipescu specimen were observed. Some twisting was notic ed, but its extent (less than 2 percent) was much less than has been n oted in shear testing with Iosipescu specimens.