I am a new member, I am learning MS at Korea. In my work, I have tested carbon sheet (plain weave) 1mm thickness following ASTM D790 standards, dimension of the specimen was 50.8x12.7x1 mm and test on 25.4mm support span. The carbon sheet was T300 TORAYCA and flexural modulus they mention is 125 GPa. But in my result, I calculated the result always about 50~55 GPa, I don't know the reason why the result unequal too much with data sheet from the manufacturer. The forcing at breaks was 33~38 Kgf.