Semester

Summer

Date of Graduation

2007

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Ruifeng Liang

Committee Co-Chair

Hota V. S. GangaRao

Abstract

Most sandwich structures are defined using a three-layer type of construction, two thin layers and a thick core layer. Typically, the thickness ratio of core to face sheet is in the range of 10 to 15. For this study, end grain balsa was used as a core material (thickness ∼3 in.) and Fiber Reinforced Polymer Composite (FRP thickness ∼0.25 in.) was used as face sheet material.;The objective of this research was to develop a modeling approach to predict response of composite sandwich panels under static bending conditions. Different model including 2D and 3D solid with isotropic and orthotropic material properties were attempted in advanced Finite Element (FE) software MSC.NASTRAN. Comparison of FE model predictions with experimental data on sandwich panel mechanical properties helped in establishing appropriate modeling approach. FEA has been carried out both the bench and full scale panel levels. The effects of different material properties and panel profiles (with caps and w/o caps) were investigated. Finally, the FEA was further extended to predict response of jointed FRP sandwich panels. Proposed modeling has been proved to give reasonably accurate prediction for composite sandwich panels under the mentioned scenarios.;Another objective of this study was to evaluate mechanical and physical properties of Carbon FRP composites including both laminates and sandwich panels. CFRP sandwich panels of 0.25&inches; thick face sheets sandwiching balsa core were produced by BRP Inc., while additional laminates were manufactured either by compression molding (CFC-WVU lab) or Resin Infusion process (Fiber-Tech.) with varying resin system, fabric architecture and 3D stitched fabric. Mechanical property evaluation of composite material was carried out on both the coupon and panel levels under bending, tension etc. Effect of different process parameters, material structure and resin on composite properties was discussed. Microstructure study of composite specimens was carried out in order to analyze fiber-matrix adhesion and void content which in turn affect the strength of FRP composites.

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