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Aerospace Engineering Commons

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Selected Works

Sunil Kishore Chakrapani

Fracture

Articles 1 - 2 of 2

Full-Text Articles in Aerospace Engineering

Inspection And Evaluation Of Dry Fibers In Thick Composites, Vinay Dayal, Sunil Chakrapani, Daniel Barnard Aug 2014

Inspection And Evaluation Of Dry Fibers In Thick Composites, Vinay Dayal, Sunil Chakrapani, Daniel Barnard

Sunil Kishore Chakrapani

This paper presents the investigation of dry fibers in thick composites. Dry fibers can be defined as lack of epoxy in localized regions. These local regions act as potential defects in thick composites under compressive loads and act as an initiation point for defects such as matrix cracking and delamination. Detection and characterization of dryness in glass/epoxy composites, with thickness greater than one inch, is presented in this paper. One inch samples with dry fibers were fabricated and tested. Detection is carried out with the help of air coupled ultrasonics in both through transmission and singled sided inspection. To characterize …


Investigation Of Waviness In Wind Turbine Blades: Structural Health Monitoring, Sunil Kishore Chakrapani, Vinay Dayal, Daniel J. Barnard Aug 2014

Investigation Of Waviness In Wind Turbine Blades: Structural Health Monitoring, Sunil Kishore Chakrapani, Vinay Dayal, Daniel J. Barnard

Sunil Kishore Chakrapani

Waviness in composite wind turbine blades was detected and characterized with the help of air coupled ultrasonics. Based on the aspect ratio, the detected marcels are either accepted or rejected. A passive structural health monitoring approach has been presented here to monitor the accepted marcels above a threshold. The fatigue life of specimen is most affected in the presence of a marcel. Hence this study focused on the damage evaluation after fatigue testing. Wavy laminate was subjected to fatigue load to investigate the fracture mechanisms near the marcel. Different types of defects were identified from this study and were used …