Composite ball bat with constrained layer dampening
A composite ball bat includes one or more dampening elements located primarily at or near one or more vibration anti-nodes of the ball bat to provide vibration dampening and improved bat “feel.” The dampening elements may be made of viscoelastic and/or elastomeric materials, and/or other vibration-attenuating materials, and may be located in the barrel, the handle, and/or the tapered or transition region of the ball bat.
1 . A composite ball bat, including a barrel, a handle, and a transition section joining the barrel to the handle, comprising:
at least one dampener in at least one of the barrel, the handle, and the transition section, with substantially each of the at least one dampeners located substantially at an anti-node of a vibration mode of the ball bat.
2 . The ball bat of claim 1 wherein the at least one dampener is bonded to surrounding composite material in the ball bat.
3 . The ball bat of claim 1 wherein the at least one dampener is 0.008 to 0.020 inches thick.
4 . The ball bat of claim 1 wherein the at least one dampener comprises at least one of a viscoelastic and an elastomeric material.
5 . The ball bat of claim 1 wherein the at least one dampener comprises a plurality of discrete dampeners, with substantially each of the discrete dampeners located substantially at a single anti-node of a vibration mode of the ball bat.
6 . The ball bat of claim 1 wherein the at least one dampener comprises a plurality of dampeners arranged in parallel at a plurality of radial locations substantially at an anti-node of a vibration mode of the ball bat.
7 . The ball bat of claim 1 wherein the at least one dampener comprises a plurality of dampeners arranged longitudinally in series at approximately the same radial location in the ball bat.
8 . The ball bat of claim 1 wherein the at least one dampener comprises a plurality of dampeners located substantially at a plurality of anti-nodes of at least one vibration mode of the ball bat.
9 . The ball bat of claim 1 wherein at least one dampener is located substantially at the anti-node of the first bending mode of the ball bat.
10 . The ball bat of claim 1 wherein at least one dampener is located substantially at the anti-node of the first hoop mode of the ball bat.
11 . The ball bat of claim 1 wherein the barrel comprises at least two walls, and wherein at least one dampener is located in each of the barrel walls.
12 . The ball bat of claim 11 wherein the at least two walls of the barrel are separated by at least one ISCZ, and wherein at least one dampener is positioned against the at least one ISCZ.
13 . The ball bat of claim 1 wherein composite material in the ball bat is fused at at least one end to form a continuous load path between the at least one dampener and the composite material.
14 . The ball bat of claim 1 wherein the at least one dampener comprises a material having an axial elastic modulus that is 0.01 to 50% of an axial elastic modulus of neighboring composite material in the ball bat.
15 . The ball bat of claim 1 wherein the at least one dampener comprises a material having an axial elastic modulus that is 0.05 to 10% of an axial elastic modulus of neighboring composite material in the ball bat.
16 . The ball bat of claim 1 wherein the at least one dampener comprises a material having an axial elastic modulus that is 0.10 to 5.0% of an axial elastic modulus of neighboring composite material in the ball bat.
17 . A composite ball bat, comprising:
a discrete first vibration attenuation element located substantially at the anti-node of the first bending mode of the ball bat; and
a discrete second vibration attenuation element located substantially at the anti-node of the first hoop mode of the ball bat.
18 . The ball bat of claim 17 further comprising at least one discrete additional vibration attenuation element, with each of the at least one discrete additional vibration attenuation elements located substantially at one of the anti-nodes of the second bending mode of the ball bat.
19 . The ball bat of claim 17 wherein at least one of the first and second vibration attenuation elements is bonded to surrounding composite material in the ball bat.
20 . The ball bat of claim 17 wherein at least one of the first and second vibration attenuation elements comprises at least one of a viscoelastic and an elastomeric material.
21 . The ball bat of claim 17 wherein the first and second vibration attenuation elements each comprise at least one material having a lower axial elastic modulus than an axial elastic modulus of neighboring composite material in the ball bat.
22 . A composite ball bat, comprising:
at least one discrete primary dampening element located substantially at the anti-node of the first bending mode of the ball bat; and
at least one discrete secondary dampening element located substantially at one of the anti-nodes of the second bending mode of the ball bat.
23 . The ball bat of claim 22 wherein the at least one discrete secondary dampening element comprises at least a first dampener positioned primarily at the anti-node of the second bending mode located in a barrel of the ball bat, and a second dampener positioned primarily at the anti-node of the second bending mode located in a handle of the ball bat.
24 . A composite ball bat, comprising:
a plurality of discrete means for dampening vibration, with substantially each of the discrete dampening means located substantially at a vibration anti-node in the ball bat and having a lower axial elastic modulus than that of neighboring material in the ball bat.