Monitoring bondline integrity via embedded piezoelectric sensors
Abstract/Contents
- Abstract
- Monitoring the bondline integrity of adhesively bonded joints consists one of the most critical concerns in the design of aircraft structures up to date. Due to the lack of confidence on the integrity of the bondline both during fabrication and service, the industry standards and regulations require assembling the composites or even metallic structure using the inefficient "black-aluminum" approach, i.e. drill holes and use fasteners. Furthermore, state-of-the-art non-destructive evaluation (NDE) and structural health monitoring (SHM) approaches are not yet able to provide mature solutions on the issue of bondline integrity monitoring. Therefore, the objective of this work is the introduction and feasibility investigation of a novel bondline integrity monitoring method that is based on the use of piezoelectric sensors embedded inside adhesively bonded joints in order to provide an early detection of bondline degradation. The proposed approach incorporates: (i) micro-sensors embedded inside the adhesive layer leaving a minimal footprint on the material, (ii) numerical and analytical modeling of the electromechanical impedance (EMI) of the adhesive bondline, and (iii) EMI-based diagnostic algorithms for monitoring and assessing the bondline integrity. The literature review indicates that the key parameter to identify the kissing bond is the stiffness of the boundary layer of the bondline, a thin arbitrary layer between the adhesive and adherends. A simple theoretical model and a more comprehensive finite element model was developed to assess the impedance based method. The experimental validation and assessment of the proposed approach is achieved via the design and fabrication of prototype adhesively bonded lap-joints with embedded piezoelectric sensors and a series of mechanical tests under various static and dynamic (fatigue) loading conditions. The obtained results demonstrate the potential of the proposed approach in providing increased confidence on the use of adhesively bonded joints for aerospace structures. Based on the experimental validation, the detection algorithms is developed with the validation test to demonstrate the feasibility to predict the mechanical performance of the bonded joints using the impedance information from the embedded sensor. The optimal design for sensor is also studied with a preliminary exploration on monitoring the fabrication process of the bonded joints.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2018 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Zhuang, Yitao |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering. |
| Primary advisor | Chang, Fu-Kuo |
| Thesis advisor | Chang, Fu-Kuo |
| Thesis advisor | Cutkosky, Mark R |
| Thesis advisor | Senesky, Debbie |
| Advisor | Cutkosky, Mark R |
| Advisor | Senesky, Debbie |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Yitao Zhuang. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2018. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2018 by Yitao Zhuang
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