Non-destructive testing of aircraft engine parts made of composite materials. Identifying the limits of acceptable defects

An important engineering challenge of providing the reliability of products made of composite materials (CM) is the identification of dangerous types of defects, their permissible values and developing techniques for their detection. A set of techniques of non-destructive testing (NDT) is presented as applied to the problem of monitoring and identification of the acceptable limits of technological defects of aircraft engine parts made of composite materials. The paper also includes experimental tests aimed at determining the effect of a fiber defect on the mechanical characteristics of a polymer composite material. Joint use of different NDT techniques is necessary for the detection of multiple types of technological defects typical for CMs. Defect detection is an integral part of the processing of composite materials into products. Test samples with artificially damaged fibers show their significant influence on tensile strength characteristics and shear modulus in the plane of the layer. The effect of possible defects on the mechanical characteristics of fiber should be considered when designing CM products.