Date of Graduation
Statler College of Engineering and Mineral Resources
Civil and Environmental Engineering
Mechanical Response of VARTM based FRP composites
The United States Department of Transportation (USDOT) recently created two new design specification for rail tank cars. These new types of classification, DOT-117 and DOT-117R, are designed with additional safety precautions to prevent hazardous chemicals from leaking out in case of a derailment. Features such as a thicker outer steel wall, head shield, and top and bottom valve protections provide additional protection compared to the current DOT-113 tank cars at the cost of additional weight. The WVU-CFC proposes a multifunctional, composite jacket that could be used in place of current tank car retrofitting methods. The composite jacket will provide the same or greater benefits in terms of puncture, fire, and impact resistance at a significantly lower unit weight and a faster retrofitting time when compared to current methods. This research covers the development of the initial sample production and testing of the proposed composite jacket samples in tension, bending, and impact.
The process of creating the composite jacket begins with designing a consistent method of producing test samples. Vacuum assisted resin transfer molding (VARTM) was chosen due to its low setup cost and high sample fiber volume fraction when compared to other infusion methods. Multiple sample infusions were performed with several different manufacturing parameters to find the best overall configuration. The final procedure was found to produce high quality, low void content samples to evaluate the different composite variables.
Next, the effect of several different variables was tested through a series of ASTM tension, bending, and impact tests. These variables included fabric type, resin, core material, the effect of fabric stitching, and the layer orientation in the samples. Through the tension testing and bending tests, base mechanical properties such as the elastic modulus, maximum tensile and bending strength, and total energy absorption were established and measured. These properties were found for each composite variable then compared to find the overall highest strength configuration. The most successful combination of variables were then tested using a drop weight impact machine to confirm these results and to compare to the DOT crash data. Through these series of tests, it was determined that an 18-layer hybrid glass/aramid fabric layup, stitched full thickness with aramid thread, infused with epoxy resin produced the highest amount of energy absorption per sample. The final optimized composite achieved nearly half of the DOT-113 energy absorption per sample volume (206 ft-lb/in2 vs 91 ft-lb/in2) with a higher fracture stress (5,694 lbf/in2 vs 7,902 lbf/in2) while having only a fifth of the density (493 lb/ft3 vs 106 lb/ft3).
Kenney, Andrew, "Mechanical Response of VARTM infused FRP composites" (2022). Graduate Theses, Dissertations, and Problem Reports. 11473.