The crack suppression effect of the modified crack arrester was evaluated by the FE analysis considering the thermal expansion coefficient and the fracture toughness test under the mode I type loading. In the fracture toughness test, interfacial crack propagated in the foam core just below the resin impregnated layer and completely stopped in front of the leading edge of the arrester. Strain distribution was directly measured with the DIC (Digital Image Correlation) method.