Effect of Adhesive Material Properties on Induced Stresses in Bonded Sensors (Preprint)
Abstract
An analysis of the stresses induced in adhesively bonded sensors from a biaxial stress field in the underlying substrate is presented. Recent Structural Health Monitoring work has looked at using surface bonded sensors to detect and characterize damage in aircraft structures. In addition to the proper design of these systems, it is important that they be able to survive in a sometimes hostile operating environment in terms of weather, vibration, temperature, and mechanical loading of the structural members of the airframe. The analysis first considers the load transfer mechanism from the substrate through the adhesive layer into the sensor. The partitioning of the load between the substrate and sensor is found to depend on the substrate stiffness, the sensor thickness, and the shear modulus and thickness of the adhesive. The analysis then shows that for an elliptically shaped sensor whose maximal dimension is small compared to the substrate in-plane dimensions the stress induced by a biaxial state of stress can be determined using inclusion theory. It is further shown that the stresses in a circular sensor on a substrate subjected to a hydrostatic state of stress can be calculated using equations derived from those used to determine the interfacial pressure for an interference fit between annular cylinders. Finally, the analysis considers induced bending stresses caused by the asymmetric change in thickness in the region where the bonded sensor resides.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2006
- Accession Number
- ADA463772
Entities
People
- James L. Blackshire
- Steven A. Martin