Damage Propagation Analysis in the Single Lap Shear and Single Lap Shear-Riveted CFRP Joints by Acoustic Emission and Pattern Recognition Approach.

Claudia Barile,Caterina Casavola,Paramsamy Kannan Vimalathithan,Giovanni Pappalettera

doi:10.3390/ma13183963

Abstract

An innovative way of using the Acoustic Emission (AE) technique is introduced in this research work. The ratio of recorded acoustic energy and the counts recorded for each acoustic event were used for characterizing Carbon Fiber Reinforced Plastic (CFRP) laminates adhesively bonded with and without mechanical fasteners. The cumulative counts and cumulative energy of the recorded acoustic events were used for identifying the critical points of failure under loading of these hybrid joint specimens. The peak amplitude distribution was used for identifying the different damage modes such as delamination, matrix cracking and fiber breakage, albeit, ineffectively. The new parameter energy per count was introduced in this work, which can successfully identify the different damage modes under loading. To differentiate the damage modes using the energy per count, they were clustered using k-means++ pattern recognition technique. The method introduced in this work can estimate the damage modes of the CFRP specimens.

Highlights

The feasibility of using composite materials in larger structures is one of the major reasons for its tremendous growth over the last few decades
Under static loading, the absolute number counts recorded depends the failure phenomenon and on how the sensors are placed on the specimen
The counts recorded for all the specimens, both Single Lap Shear (SLS) and Single Lap Shear with Rivets (SLS-R), they are normalized for comparison

Summary

Introduction

The feasibility of using composite materials in larger structures is one of the major reasons for its tremendous growth over the last few decades. The need to join structural composites in a larger structure is inevitable. Joints are considered potentially the weakest link of a structure. It becomes essential to study the strength and predict the failure of the joints [1,2]. Composite structures can be joined mechanically by using mechanical fasteners or bonded adhesively. The combination of these two methods, typically known as ‘hybrid’ can be used for joining structural composites

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Conclusion