Date of Award

6-2009

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Mechanical Engineering

First Advisor

Rebecca Cortez

Second Advisor

Michael Hagerman

Language

English

Keywords

bat, carbon, aluminum, bats, test

Abstract

Softball bats have evolved over the past thirty years through improvements in materials. Bats have evolved from aluminum, to carbon fiber, to carbon fiber reinforced with carbon nanotubes. Many bat manufacturers claim to have the best performing bats on the market, which makes the consumer wonder which bat will actually give them that “edge” over the competition. To determine this, an aluminum alloy bat was compared to a composite bat containing carbon fibers dispersed with carbon nanotubes, in a series of three tests. The first test was a compression test that experimentally tested the bats’ mechanical properties under compression loading. It was found that the stiffness of the aluminum and carbon nanotube bat was 2918 lb/in and 1130 lb/in respectively. The second test analyzed a video of a live batter hitting a ball to calculate the ball’s exit velocity using each bat. The CNT bat significantly outperformed the aluminum bat with an average exit ball velocity of 85.5 mph compared to 72.5 mph. The third test was to compare the “sweet spot” of each bat using an experimental modal analysis, in which an input force was applied and the vibration response was measured. In addition to these tests, the composite bat was dissected and imaged using microscopy techniques to determine how the nanomorphology influences its physical properties and performance. The attempts at sweet spot testing and imaging yielded inconclusive findings

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