Semester

Spring

Date of Graduation

2004

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Jacky Prucz.

Abstract

This research assesses the effects of stitching a four-layer E-glass/Epoxy cross-ply laminate with translaminar reinforcement consisting of E-glass yarns. Both experimental characterization and finite element analysis have been employed to accurately predict and analyze the properties of the stitched material.;Tensile and Double Cantilever Beam testing indicated that translaminar stitching degrades the effective extensional modulus of the laminate by about 15.9 percent, while it enhances the opening Mode I interlaminar fracture toughness. This degradation in the effective in-plane stiffness is attributed to the localized damage inflicted on the fiber plies by the needle penetration of the sewing machine used to insert the transversely reinforcing stitch.;The finite element model predicted a more rigid effective extensional modulus of 2.44 MSI, which is approximately 2.9 percent higher than the corresponding experimental value of 2.37 MSI. This difference can be attributed to slippage effects along the fiber-matrix interfaces being prevented in the model.

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