2005 2 A simple estimate of laminated composite materials’ strength characteristics ∗ Nguyen Duy SINH ∗ ( : ) 3 Key Words : composite materials, laminate, strength characteristics, layers debonding 1. FRP (CFRP) (GFRP) CFRP GFRP FRP FRP 2. ¯ C = C M {C M - (1 - f )(C M - C I ) S} −1 × [C M - (C M - C I )] {S - f (S - I )} f C I C M S Eshelby 3 1) 3. B1 B5 F1 F5 H1 H5 2) –1 H1 4. (1) –2 –3 x θ =0 ◦ 5% (2) – 4 ((G2) 4 ) θ =0 ◦ θ = 90 ◦ (3) –5 –6 y 10% (4) –7 (1)