Structural Event - Concrete Baseball Bat

There have been questions regarding this event. Please refer to the FAQ HERE for answers to the questions.

 

Introduction:

Teams will design and construct a baseball bat made of concrete.  Given the requirements below, teams will have a chance to produce the most cost and strength efficient bat and apply the bat to a practical application.  Teams will compete to hit balls the farthest.  The best overall score will win the competition.

Construction Rules:

  • This competition is for undergraduate students only.  General guidance from other sources is encouraged but all the work is completed by undergraduate students.
  • Bat length must be between 28” and 34”. No portion of the bat can be larger than 6” in width. This will be tested with a box (similar to steel bridge competition) where the inside dimension of the box will be 6”x6”x34” (WxHxL).  The bat must look like a bat, meaning the handle of the bat must be at most ½ the diameter of the barrel of the bat and there must be a taper between the barrel of the bat and the handle.
  • Reinforcement fibers and meshes are allowed and encouraged for safety.
  • Each bat must have at least one reinforcement bar (1/2” max.) spanning the length of the bat with a minimum of ½” cover on all sides.
  • Molds will not be provided to schools to allow creativity of design.
  • No paint, tape, or external coatings of any kind are permitted; the bat must look like it is made from concrete. Magic marker is allowed, only for identification.  Please mark the bat with school identification on the barrel of the bat.  Figure 1 shows terminology and an example of identification.
  • Each school can enter only one bat for the competition.
  • A separate exact duplicate section must be made of the barrel of the bat (the part where the bat will hit the ball).  This section must be 24” long and will be tested for flexural strength and compared to flexural strength estimates. The span length will be approximately 18” and testing will be similar to ASTM C78/C78M. Violations of not exact duplication will result in disqualification.
  • A professional concise 2 (two) page report must be turned in at time of competition.  This report must describe your design, flexural strength estimate, construction, and overall cost to make this bat.  For cost, please include a section for materials, construction cost, and labor of all items including the mold.  (Generally assume: Student = $10/person/hr, Contracted Professional = $100/person/hr; Any donated items must be priced as if you purchased them)  Include concise and professional calculations and photographs of the construction process in the appendix of the report (not included in the 2 page limit).
  • Points will be given on a variety of factors (see Scoring Section on next page).  As engineers, it is important to always find the most efficient solution to a problem, therefore judged factors include cost, weight, batting effectiveness, and professionalism.

Competition Rules:

Each team will have the opportunity to hit a softball off a tee a maximum of 10 times (5 times for male batter, 5 times with a female batter, and teams must alternate batters, between males and females, between hits.) or until the bat loses its structural integrity (per judge’s discretion due to safety).  Each ball will be allowed one foul, which includes a missed swing or coming to rest out of bounds. Gloves, batting helmets (not hard hats), and safety glasses are required and will not be provided by host school.

Scoring:

Possible Points

Judged Item

20

Initial overall bat appearance

20

1 point per ‘in play’ ball

20

2 page report (described above)

20

Flexural strength estimate compared to actual flexural strength

20

Costs (described above, cheapest bat = most pts)

20

Weight of bat prior to competition (lightest = most pts)

20

Accumulated distance of ‘in play’ balls (Longest tot. dist. = most pts)

Total possible points: 140 pts

 

 

Figure 1. Baseball bat terminology and example of identification.