Anderson Bat Company’s Response to the NCAA Moratorium Composite Bats

July 23, 2009

We are responding to NCAA’s request for a reply to the memo in which the NCAA proposed an immediate and indefinite moratorium on composite bats for NCAA play. Our answer is complete concurrence. In addition we offer our congratulations for the courage to make such a bold and much needed move. In the interest of safety for the student/athlete, it is important that every participant in an at-risk activity have full disclosure of the danger they subject themselves to and that those risks are not unduly increased without their prior knowledge. In terms of the integrity of the game, it should be held that all of the rules be upheld equally for everyone and intentional disregard for the rules is not acceptable. Based on those grounds the NCAA action is well founded in their proposed moratorium.

We’ve taken the liberty below to explain the underlying technical issues as we see them and then to voice our opinions about the feasibility of the construction method being satisfactorily improved and the validity of the testing that is currently in place.

The composite dilemma is based on a flawed design concept wherein there is no viable solution without a major advancement in materials technology. Now, whether or not the designers purposefully allowed for the product performance improvement is not the issue. The question at hand is simply this; does the performance improve with ongoing play? Does the ABI protocol prevent the improvement? Can this problem be comprehensively addressed without a major engineering redesign? Our experience tells us that the problem can eventually be solved but it is not economically plausible with the materials available today and the ABI test is inadequate.

We spent hundreds of thousands of dollars while contracting several of the composite industries most noted experts to produce a fiber reinforced composite product. We found no reasonably equitable solution to the delamination problem that offered both suitable initial and stable performance and predictable durability. We abandoned the effort to pursue alternative development projects.

The word “composite” is not specific to any certain materials or methods so for the purpose of this document the use of the term “composite” will be used specifically to denote the fiber reinforced (resin-over-fiber) construction used in building a “composite” bat. Fiber reinforced composites have a main body made of epoxy and the naturally brittle epoxy is reinforced with long fibers of fiberglass and graphite in order to increase the strength of the final product.

The gravest concern for a composite structures engineer after finishing the primary shape design is the development and growth of a delamination-intralayer/interlayer crack system under axial compressive cyclic (fatigue) loading. This predicament is not only present in Baseball and Softball bat design; it is exacerbated by the added stress of violent impact as opposed to simple load cycling. The mechanical behavior and the life expectancy of a composite component is dependent upon the absence of interlayer and intralayer delamination.

An interlayer delamination is a crack that grows in the interface of two layers without breaking the layers. That means that the crack remains in the same direction between layers. If delaminations are of the interlayer type, it is probable that they will become intralayer with additional impact.

An intralayer delamination is a crack that, while it grows in the interface, occasionally "jumps" to a neighboring interface. Then it breaks one, or more, of the layers and it also changes orientation. Intralayer delaminations are more likely to grow catastrophically and lead to destruction of the component.

It is this intralayer self-destruction process that causes the unstable performance and failure issues for fiber reinforced composite bats. This is a common concern for all fiber reinforced composite structures under compressive cyclic loading and it is the reason that this method of construction is inherently unsuitable for impact applications.

The explanation for the bat barrel becoming more reactive is that while the inner layers break up and become more pliable the remaining undamaged layers remain stiff and the flexural response increases. The addition of flexural response increases the impulse time of the kinetic event and transfers energy to the flight of the ball much more efficiently. There is no single or simple measurement of flexural response and/or impulse time. The measurement would have to include stiffness, response time and outward force measurements.

The ABI protocol does not prevent any of this from happening. In fact the ABI protocol actually proves it can and does happen. In the ABI protocol the initial damage is done and the additional performance is measured. If the additional performance is below the specified limit in spite of the improvement it passes! Essentially what they are testing is the beginning of an unpredictable and unstoppable performance increase and eventual catastrophic failure. For this test to be worthy it should measure that there is no additional performance beyond legal limits up to either the beginning of a performance decline or product failure.

In conclusion, we are of the opinion that the NCAA ban is not only justified but necessary. Moreover, we believe that the ABI protocol is incomplete and ineffective and should not be the standard by which the new products should be approved. The technical portion of the document is a light overview and in no way a complete description. If you have any questions or want more information, we are at your service.