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Bat Presentation

Bat Presentation. Lauren Barker. Target MOIs Initial Shell – 2400 Final Bat – 4500 Measured MOIs Initial Shell – 2794 Final Bat – 4533.418 Initial Shell error - 16% Final Bat error - 0.733%.

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Bat Presentation

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  1. Bat Presentation Lauren Barker

  2. Target MOIs • Initial Shell – 2400 • Final Bat – 4500 Measured MOIs • Initial Shell – 2794 • Final Bat – 4533.418 Initial Shell error - 16% Final Bat error - 0.733%

  3. I was under the assumption that I would be able to add the half inch long endcap so that my final bat length would be 28.5. Since there were none left, I had to have the bat suspended in the knob resin about 0.25 inches off the ground. I measured the bat to the adjusted 28.5 inches and taped it to the wall very well. Andrew emailed me saying that the final length was 28.25 inches. Even if the length was actually 28.5 inches, the percent error would have still been under 3%.

  4. Since I was told that all the 6-layer bats fabricated in groups this year came up with unreliable MOIs, I focused on data from last year. 6-layer bats (2008) Length SW-oz S-MOI TW-oz F-MOI 28.5 14.30 2025 20.37 3913 29.1 14.46 2435 18.84 3560 30.316.43 3022 20.44 4567

  5. My plan was to start with a 30 inch bat and expect to cut off half inch • 29.5 inch final bat • handle angle 35 less  dense than larger angle • barrel angle 65 less  dense than smaller angle • 2 oz knob  heavier bat means greater MOI • taking an inch or two off knob keeps final MOI high and makes for a high CM value

  6. Group B Length 30.88 in. Mass 10.60 oz. Initial Shell MOI 1950.45 CM 16.25 in. • The length is 0.38 inch greater than max. specification and MOI is still 450 too low.

  7. Group F had very suspicious data this year (Shell MOI 1700), but all the six layer bats supposedly had suspicious data. I figured it was possible that the 4 layer bats were too high. • There was a huge discrepancy between the two 8 layer bats and their lengths were only 0.5 from each other (4095 and 3144)

  8. None of this year's data seemed consistent or necessarily accurate • The lengths this year were generally longer than last year, but the weights were significantly less.

  9. Group E's Shell MOI was deemed suspicious data. Even if the real MOI should had been 2800, I would have been able cut off another 1.6 inches to lower the MOI to my target of 2400. Cutting an inch off the barrel end of a 6 layer bat lowers the MOI by at least 300. Another 0.6 inches taken off the barrel would certainly put the shell MOI below 2400.

  10. My individual bat layers did not always end up with the braid angles I had requested, especially at the barrel where it counts the most (46° and 50°). I chose braid angles that yielded the lowest density based on previous data. It was fairly important that I got somewhat accurate braid angles because I needed to fabricate a low density 6-layer bat. • Group C had an average braid angle at the barrel of 49°, and their bat came out with the highest linear density by far.

  11. Group Length Weight Final MOI CM E 30.10 16.10 2206.80 17.60 D 30.9 10.7 2555.09 20.3 • It sounds unlikely that Group D's bat would be over 6 oz less than that of Group E, especially since Group D's bat was 0.8 inches longer. • Even if Group D's shell MOI was actually 3000, cutting up to 2.4 inches off the barrel end could have made the MOI less than 2400.

  12. Complete Bat # layers 6 Length 31.00 in. Weight 21.95 oz. Final MOI 5253.84 CM 19.00 in. • The length of this bat is a couple inches longer than the max. our individual bats are allowed. Cutting a couple inches off the barrel end when it was a shell would certainly have yielded a lower final MOI. • I could have made my knob only 0.5 oz. Adding mass always increases the MOI. • I could have used less resin for my endcap if the MOI was still too high. • Group E ended up with the second highest final MOI for the 6 layer bats, and the data was not labelled suspicious. • Group F came up with a final MOI of 6009, but I do not believe that a six layer bat could have a higher MOI than an 8 layer bat of the same length, so I ignored that data.

  13. Project 5 • The assignment was to develop a theoretical analysis of the MOI-6 measurement error. • In the MOI-6 equation, the mass, length, center of mass, and period of the bat are all variables that cause error. Hypothesis: • The period of the bat will have the most standard deviation because in the formula, it is squared. Therefore, any error in the period measurement is squared.

  14. Project 5 Let standard deviation = d Assume: • M = 13 oz dM = 0.1 oz • L = 29 in dL = 0.25 in • MC = 12 in dMC = 0.33 in • T = 1.35 sec dT = 0.8 sec

  15. Project 5 • dI6 = [386(L–MC-6)(T2)/4Л2 ]* dM + [386(M)(T2) / 4Л2] * dL + [386(M)(T2) / 4Л2] * dMC + [386(M)(L–MC-6)(T2)/4Л2 ] * dT • dI6 = [386(29 – 12 – 6)(1.4)2 /4Л2] (0.1) + [386(13)(1.4)2/4Л2](0.25) + [386(13)(1.4)2/4Л2](0.33) + [386(13)(29 - 12 - 6)(1.4)2/4Л2](0.08) • dI6 = 21.080 + 62.283 + 82.213 + 219.235 • Evidently, the period caused the largest error by multiple factors for each of the other variables. Errors in T would have been larger if not measured at 6 inches from the handle.

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