Tooth Morphology and Mechanical Stresses

Overview

During the evolutionary process of tiger shark teeth, secondary serrations have emerged alongside the primary serrations. Dr. Todd Cook, a biology professor at Behrend and the sponsor of this project, is interested in investigating whether the presence of these secondary serrations offered any biological advantages during the feeding process. 3D printable testing components that can be incorporated into the MTS tensile test machine were designed and prototyped.

Objectives

The objective of this project is to construct a testing device that will be used to investigate how the morphology of shark teeth serrations affect forces during feeding. To achieve this, tests will be conducted using a tensile testing machine to measure the forces generated by different types of serrations when vertically drawn through an inorganic medium.

Approach

• Met with Dr. Todd Cook to define project specifications.
• Met with a scientist from Allegany College who conducted similar research
• Performed concept generation and used weighted decision matrices to rank ideas.
• Created CAD models of Testing Device components using Autodesk Inventor.
• Performed rapid prototyping using Innovation Commons’ printers and a personal 3D printer.
• Created multiple prototypes.
• Refined design based on prototype failure and ANSYS analysis.
• Tested out various mediums: ballistic gelatin and three types of foam.
• Performed testing on the MTS tension testing machine.
• Analyzed data from testing by creating graphs.

Outcomes

The subsequent findings were obtained from both the design and assessment of the device:

• The budget-friendly medium that produced the best force output for testing is FloraCraft FloraFom.
• Tests run at higher speeds output a higher force.
• The evolution of secondary serrations does not have a large effect on the cutting forces as the tooth with no secondary serrations outputted the same cutting force as the tooth with the most secondary serrations.

• It is highly likely that the geometry of the shark tooth effected the produced cutting forces and that the variable of interest, secondary serrations, was not properly isolated.
• A larger data pool from more testing is necessary for a more definitive conclusion from the data analysis.