Fiber reinforced laminated composite materials are widely used for various structures especially for aviation and aerospace structures because of their high strength and stiffness-to-density ratios and superior mechanical properties.However they are easily damaged due to impact load because of their low toughness.Especially in low velocity impact, impact damage is initiated in the structure or opposite side of impact surface.It is hard to be detected in its appearance and can significantly reduce residual strength of the composite structures especially for compressive strength.Therefore, impact damages and residual strength should be considered in design of composite structures and reliable analysis method is required.