Question

N7. At a critical location of a composite structure, strains are measured with three strain gages glued to the surface of the composite. The orientations of the strain gages are 0 , 120 and 240 . Each strain gage measures only the strain in the direction of the gage. The strains from the strain gages are 0 = 1.0 % 120 = 0.2 % 240 = - 0.6 % The layup at this location is (+45 ,-45 )2s. The strains are assumed to be uniform through the thickness of the structure. What is the Factor of Safety against fiber fracture at this location of the structure? The composite is assumed to fail when the tensile strain in the fiber direction reaches 1.5% or the compressive strain in the fiber direction reaches 1.0%. No other failure modes need to be considered. Hint: first calculate all strains in a global coordinate system.

Answer 1

ヘ·ヒ EE-0. 006 2一

0.0 0.0019 FOs