Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

M.S. in Engineering Science

First Advisor

Prabhakar R. Mantena

Second Advisor

Prabhakar R. Mantena

Third Advisor

Arunachalam M. Rajendran


University of Mississippi

Relational Format



In this study, the effects of through-thickness stitching on the dynamic properties, low-velocity impact and shock responses of stitched and unstitched E- and S- Glass/Vinyl Ester composites have been investigated. The stiffness and loss factor (inherent damping) properties are obtained from impulse-frequency response experiments using the hammer excitation method. Drop weight impact testing machine was used to carry out low-velocity punch shear tests on the composite specimens following ASTM D3763 Standard, and shock tube apparatus was used to determine center point deflection under blast loading. The stitching increased the dynamic flexural modulus by 13% for E- and 8% for S- Glass/Vinyl Ester composites but had minimal change in the case of loss factor. The stitching also demonstrated approximately 20% increase in total energy absorption and approximately 40% increase in fracture energy for E- Glass/Vinyl Ester while showing approximately 12% increase in total energy absorption and approximately 30% increase in fracture energy for S- Glass/Vinyl Ester. Under shock loading, the stitched E- Glass/Vinyl Ester specimens exhibited lowest center point deflection of 3.7 mm center point displacement, indicating greater resistance while the rest had values within the range of 4 mm to 4.5 mm. The average energy absorption up to the point of maximum deflection was higher for the unstitched specimens compared to their stitched counterparts.


Mechanical Engineering



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