Semester

Summer

Date of Graduation

2023

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Hota V.S. GangaRao

Committee Member

Ray Liang

Committee Member

Chao Zhang

Abstract

Evaluations of FRP Composite Coupons Under Impact and Puncture

Lekhnath Bhandari

Railroad tank cars are the main mode of transportation for carrying flammable liquids and other hazardous materials, in any mode of ground transportation system. These tank cars, if punctured during derailments may explode releasing large amounts of hazardous materials and posing serious threats to human life and leading to economic losses. To minimize such catastrophes, in 2015, United States Department of Transportation (USDOT) proposed to improve the thermal and puncture performances of these tank cars and introduced two new design specifications: DOT-117 and DOT-117R. Tank cars with 9/16 inches AAR TC 128 steel inner tank body, a ½-inch thermal protection system and an 11-gauge A1011 outer steel jacket along with other safety enhancements such as protected top fittings, fully protected head shield and bottom outlet valve are new non-pressurized DOT-117 tank cars. Tank cars that have been retrofitted to satisfy the DOT-117 specifications, to include a jacket and head shield are of the DOT-117R class. Using the best quality thicker steel can improve the impact and puncture resistance of tank cars but reduces the car’s payload because of significant self-weight increase. Moreover, it increases fuel consumption and transportation costs, which are not desirable for the stakeholders.

West Virginia University Constructed Facilities Center (WVU-CFC) proposed the multifunctional composite jacket containing sacrificial layers and intumescent coating to be wrapped over existing steel tank cars, providing a cost-effective retrofit solution. WVU-CFC came up with a combination of materials and manufacturing technique for the polymer composite jacket. Making use of these materials and manufacturing techniques, composite coupon specimens were manufactured and tested under static and dynamic loads as per the ASTM standards to determine their impact and puncture behaviors.

Different parameters associated with the puncture and impact behavior were evaluated. These parameters are fabric combinations and stacking sequences, thru-thickness stitching of fabric layers, resin types, core materials, and increase in number of fabric layers in composite jacket. These parameters were studied and modified based on the results obtained from static and dynamic tests on coupon specimens to obtain the most efficient composite jacket. The best performing composite coupons were then tested in the presence of foam and steel substrate under static puncture and dynamic impact loads to determine their puncture and impact behaviors in a real tank car scenario. These test results were then compared with DOT-117 tank cars test results to confirm the superior puncture and impact performances of the composite jacket manufactured by CFC-WVU. It was observed that the composite jacket manufactured by CFC-WVU, being 4.3 times lighter than DOT-117 outer steel shell, is about 1.9 times better (1463 ft. lb./lb. vs 786 ft. lb./lb.) in terms of specific energy absorption under dynamic impact loading. Moreover, the combination of composite jacket, foam, and steel, at composite failure, is about 2.1 times better than DOT 117 outer steel shell (1608 ft. lb./lb. vs 786 ft. lb./lb.) in terms of specific energy absorption under dynamic loading. If the combination of steel, foam and composite jacket could be tested up to steel failure, the ratio would be much higher than 2.1.

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