Effect of delamination on the dynamic characteristics of thin‐walled carbon fiber‐reinforced polymer tube

Abstract Thin‐walled carbon fiber‐reinforced‐polymer (CFRP) tubes are susceptible to damage, which impacts their dynamic characteristics. This paper investigates the influence of delamination damage on the dynamic properties of thin‐walled CFRP tubes through finite element simulation and experimental methods. A transversely isotropic principal model is employed to establish the geometric model. Delamination damage is induced using the cohesive zone model and the secondary stress criterion. Both circumferential and elliptical delamination cases are studied. The modal test is conducted using the hammer excitation method. It is observed that the finite element model aligns with the experimental results. It is discovered that the larger the delamination size, the lower the natural frequency for a given damage location. The location of the delamination within a single layer has minimal effect on the natural frequency. The natural frequency exhibits a symmetrical pattern of decreasing and then increasing as the delamination shifts from the sides toward the center layer. Positional information is discernible in the modal shape, which can be utilized for delamination detection and localization. Highlights The damage model is built by transversal isotropic equation and cohesive unit. Finite element model is built with various delamination sizes and locations for two cases. Modal tests are performed on CFRP tubes and obtained good accuracy. Effect of delamination size and location on dynamic parameters is discussed.