1The Evolution of Materials and Technology Used to Manufacture Baseball/Softball BatsbyRyan D. DeLandSchool of EngineeringGrand Valley State UniversityResearch PaperEGR 250 – Materials Science & EngineeringSection 03Instructor: Dr. P. N. AnyalebechiApril 7, 20062AbstractBaseball/softball bats have been evolving since the sport’s beginning as hitters try to gain a competitive advantage on the field of play. Wood bats have evolved from heavylog-like objects to skinny handles and thick barrels. They have a small ‘sweet spot’ and are prone to breaking. Aluminum bats are more durable than wood bats and perform at a higher level. Aluminum bats produce higher batted ball speeds than wood bats due to thetrampoline effect. Composites are the new trend for bat manufacturers. Composite bats can be more easily tuned than any other material currently used to make bats, but it is new technology and manufacturing processes are still evolving. Wood-composite bats are being made to perform like wood bats in order to reduce cost to major league baseballteams. They perform just like a wood bat performs except for the bats are much more durable. Titanium bats were only briefly allowed on the field of play. The high strength-to-weight ratio of titanium produces a high trampoline effect resulting in batted ball speeds too dangerous for defensive players. Baseball/softball bat technology has evolvedfor over 150 years and will continue to evolve well into the future as hitters strive to improve their success at the plate. 1. Introduction People began playing baseball informally in the early 1800s. By 1846 the first official baseball game had been played between the New York Knickerbockers and the New York Baseball Club. In 1876 the first major league was formed known as the National League. [1]Since the early 1800s baseball has evolved and continues to evolve. Players are continually looking for that competitive edge over their opponents. Ted Williams one of the greatest hitters ever to play baseball described hitting as one of the most difficult tasksin sports. A hitter has to accelerate the bat while bringing it into alignment with a movingobject that is flying an unpredictable path at varying speeds so that the ball is driven into fair territory. [2]In order to make hitters more successful engineers and designers have developed and continue to develop new ideas and materials that can be used to design a baseball/softball bat. Natural wood bats have faced many changes since their arrival in3the 1800s from their stick like features to bats with skinny handles and fat barrels. The properties of early aluminum bats arriving in the 1970s did not even come close to those of modern aluminum bats. Composite materials arriving in the late 1990s have made a fair amount of headway and now compete with aluminum bats. Composite bats can be tuned and engineered to behave to almost any requirement. Hybrid bats are becoming ever more popular as they combine the best properties of composites and metals. Titanium was briefly used to make bats because of its high strength-to-weight ratio. The baseball bat has evolved for hundreds of years and will continue to evolve well into the future. 2. Description of Product2.1 Functional RequirementsBaseball bats experience extreme forces during use. Pitchers can throw a baseballup to around 45 m/s (100 mph) and many hitters can generate bat speeds greater than 45 m/s (100 mph). Hitters only have split seconds to first decide if the pitch is a strike, and second to be able to make contact with the ball putting it in play. The impact between bat and ball is extremely violent. A ball traveling at high speeds faces impact and then almost instantly changes direction traveling at an even greater velocity. For instance a baseball weighing 0.145 kg traveling at a speed of 40 m/s(90 mph) will collide with a bat and have contact for roughly 0.7ms generating an average force of about 18,000 N. [3] 2.2 Required PropertiesBaseball bats experience extreme forces when contact occurs, therefore they must allow repeated elastic deformations to occur without product failure. Failure for a bat would be denting or shattering when contact is made. Therefore, hitters require baseball bats that are light and strong. Bat designers are always trying to use materials that have high strength-to-weight ratios. Less mass makes for a lower inertia allowing a hitter to produce higher bat speeds. But, when mass is decreased the collision becomes less4effective. If swing speed is kept constant, a heavier bat will always send the ball further and faster. Actual bat weight is important but there is also bat swing weight, which is important to consider when designing something which functions by swinging. Swing speed involves the location of the center of mass on the bat. The closer the center of mass is to the handle the easier it is going to swing. Figure 1 shows three wooden bats ofvarying weight and one aluminum bat. The red line indicates the center of mass. The wood bats all have their center of mass in roughly the same location. The aluminum bat has a center of mass closer to the handle of the bat. The aluminum bat is the heavies bat shown, but regardless of weight it can be swung at the highest speed because of the location of the center of mass. The center of mass greatly affects a bat’s moment of inertia. The lower the moment of inertia, the faster a hitter can swing the bat. Engineers and designers keep this in mind when designing a new bat that is made out of composites or metal. It is difficult for wood bat makers to move the center of mass without compromising the bats functional requirements. [3] Figure 1 – The red line indicates the center of mass of the bats which affects swing speed.The aluminum bat has a center of mass closer to the hands than the wood bats. [3]The ‘sweet spot’ of a bat is also important to designers. The ‘sweet spot’ of a bat is the place on the barrel where the highest 10% of batted ball speeds are obtained. The only way the ‘sweet spot’ of a wood bat is altered is by the quality of wood used. Low quality wood will result in a small to almost non-existent ‘sweet spot’. High quality wood bats contain a ‘sweet spot’, but it is much smaller compared to bats made of metal5and composite materials. Metal and composite bats can be designed to place the ‘sweet spot’ in almost any location.