1 / 14

Correlation Between Bat Performance and Hoop Frequency

Correlation Between Bat Performance and Hoop Frequency. Dan Russell. Kettering University, Flint, MI. drussell@kettering.edu. Bending Modes ( common to all bats ). 160 Hz. 600 Hz. Hoop Mode ( unique to hollow bats ). 1500 Hz. What is the Trampoline Effect?. Ball impacting solid bat.

Renfred
Download Presentation

Correlation Between Bat Performance and Hoop Frequency

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Correlation Between Bat Performance and Hoop Frequency Dan Russell Kettering University, Flint, MI drussell@kettering.edu Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 1

  2. Bending Modes(common to all bats) 160 Hz 600 Hz Hoop Mode(unique to hollow bats) 1500 Hz Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 2

  3. What is the Trampoline Effect? Ball impacting solid bat Ball impacting hollow bat Movie courtesy of CE-Composites, Ottawa, CA Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 3

  4. hysteresis force compression Simple Model  Trampoline Effect mass-spring model of ball & bat (racket, club) Ball modeled as a non-linear, damped mass-spring system with initial velocity Bat modeled as a linear, damped mass-spring system initially at rest and fixed to rigid foundation Set bat stiffness s2 s2 / m2 = w2bat Hoop frequency of barrel Solve the coupled equations of motion numerically Determine BBCOR = v1out / v1in for a given bat stiffness s2 Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 4

  5. Optimal Bat hoop frequency tuned for maximum trampoline effect Elastic Bat bat deforms, ball deforms less (energy lost)bat < (energy lost)ball Very Stiff Bat ball deforms more, energy lost Soft Bat ball does not rebound Simple Model  Trampoline Effect ball parameters  softball Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 5

  6. Hoop Frequency & Barrel Construction 34-inch slow-pitch softball bats bending and hoop frequencies extracted from modal analysis Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 6

  7. Hoop Frequency & Performance ASA era study Slow-pitch Softball BatsASTM F2219 Cannon fires ball at 110mph towards stationary (pivoted) bat Batted-Ball Speed calculated from vout/vin, MOI, impact location Wood Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 7

  8. Hoop Frequency & Performance Crisco & Greenwald Batting Cage Study 19 players (HS through minor league) pitched balls (66mph) 6 baseball bat models (several of each) BBCOR values extracted by Alan Nathan Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 8

  9. Hoop Frequency & Performance Could hoop frequency be used to detect illegally altered bats? Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 9

  10. Portable Pendulum Test Concept: Use a very heavy, very stiff “ball” to impact bat barrel. Measure contact time between “ball” and bat. Contact time determined by mass of “ball” stiffness of bat Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 10

  11. Portable Pendulum Test Direct correlation between contact time & hoop frequency Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 11

  12. Portable Pendulum Test ASA era study Slow-pitch Softball BatsASTM F2219 Cannon fires ball at 110mph towards stationary (pivoted) bat Batted-Ball Speed calculated from vout/vin, MOI, impact location Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 12

  13. Portable Pendulum Test Altered bats (barrel compression test) robot swings bat at 60mph towards stationary ball Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 13

  14. Future Work Portable Pendulum Tester Digital readout Swing bat against stationary “ball” include mass/MOI properties of bat Scan along barrel Further correlation of data with measured performance Need additional bats (with performance data) Need some funding ($3,000) Dan Russell “Hoop Frequency & Bat Performance” SGMA Baseball & Softball Council Fall Meeting 2004 Page 14

More Related