Baseball bat model identification and detection of system changes through in situ experimental modal models developed on the field

Certification testing of baseball bat equipment is performed to ensure that a bat is in compliance with governing body (e.g. NCAA) regulations which are put in place to maintain the integrity of the game. At times, players have used bats that are illegally "doctored" to gain advantage in play. An in situ test is being investigated to use measured experimental modal data for comparison to existing analytical models. Model updating methodologies are employed to identify changes to the qualified bat configuration. In preliminary studies with wooden bats, changes in the system mass can be quantified and location of change identified. The techniques will be extended to aluminum bats where significant "doctoring" of the bat is more easily achieved by a variety of means than in wood bats, where corking in the most common illegal change in the bat.