Ultrasonic characterization of polymer infiltration into foam materials

The development of advanced multi-material systems has become increasingly complex with regard to performance requirements, tailorable material options, and recent innovations in manufacturing technologies. The increased development and use of engineering foam material systems, for example, has recently led to significant improvements in the weight, cost, and performance of materials used in insulating, thermal protection, sound deadening, and lightweight structural materials. An important aspect of such complex multi-material systems includes the ability to effectively join two or more materials and characterize the processing results. In the present effort, the use of ultrasound for characterizing the infiltration of a polymer material into a foam is investigated using computational models and experimental validation studies. Characteristic pulse-echo signal responses utilizing time-of-flight reflection and attenuation were used to provide an effective means for estimating the fill-factor of the polymer into a foam material, where optimization of the thermal and structural performance of the material system is desired.