Bonded joints and non-destructive testing: Bonded honeycomb structures—2

Abstract This is the second of two parts of a paper giving a comprehensive survey of ndt methods for evaluating adhesive bonded honeycomb structures. In part I the utilization of sandwich structures on modern aircraft and important design factors such as impact, fatigue, and environment were discussed. Materials used in the fabrication of honeycomb structures were presented to show the complex nature of these assemblies. Non-destructive test methods presently used to evaluate honeycomb structures were also described. Those methods, described in part I, included Verifilm, Meseran, leak test, holographic interferometry, ultrasonic, tap test, eddysonic, and sonic resonance. Thermal or infrared, and x-ray readiography are discussed in the second part of the paper. Part II also discusses and describes reference standards and acceptance standards as related to honeycomb structures. The applications and limitations of each ndt method are summarized along with the merits of bond testing methods for honeycomb assemblies.