Viscoelastic Evaluation of Composite Materials by Non-Contact Air Coupled Ultrasonic Transmission Method

The viscoelasticity of composite materials is one of the important mechanical properties to characterize the intrinsic damping mechanism, which is a crucial evaluation index for the safety performance of materials. In this paper, an approach to viscoelastic evaluation is proposed by the non-contact air-coupled ultrasonic transmission method (NACUTM). The theory of viscoelasticity evaluation is presented, and a batch of carbon fiber composite materials with different pores were evaluated. The porosity of the carbon fiber composite material can affect the ultrasonic attenuation coefficient and viscoelasticity of the material, and it was found and compared with the C-scan test result. The results were consistent with the expected value, which verified the feasibility and accuracy of NACUTM in material viscoelastic evaluation, and provided a new method for dynamic mechanical property evaluation and safety evaluation of the composite materials.