Crocodilian Jaws
Understanding Levers and Finite Elementa subdivision within the material that is relatively simple in shape, such as a tetrahedral or hexahedral, defined by vertices called nodes. Method Using Crocodilian Jaws.
Gharials and alligators have very similar bodies, but they have very different jaws. The alligator has a short and stought jaw while the gharial has a long and slender jaw. We use the the differences is the jaw geometries to explore lever system and show how their effects on forces and range of motion. Beyond the motion issues the gemetry differences impact the strength and stiffness of the jaws. In order to explore stuctural issues the concepts of loads, stiffness, and deflection are introduced. Finally the finite element method is introduced as a method for solving structural problems involving complex shapes such as jaws. The results of a finite element analysisAnalysis of the physical behavior of a finite element model. In this analysis a given physical "treatment" is applied (such as force loading on some elements), followed by computation of the effects of this treatment on other elements of the FEM. More specifically, the analysis phase involves solving a set of simultaneous algebraic equations in which the unknown variables that are solved for in this system of equations are the unknown nodal degrees of freedom. Once the values of the unknown nodal degrees of freedom are found, the unknown reaction forces are determined. Next, the spatial variation of the primary field variables within each element is computed using the element's predefined interpolating polynomials and the element’s nodal values. Thus, for solid elements this results in mathematical functions that completely define the displacement field within every finite element. These functions are then differentiated to obtain the complete strain field within each element which, when combined with known material properties of the element, yields the element stress field. In summary, the finite element solution will yield 1) the reaction forces necessary to maintain static equilibrium of the system, 2) the displacement field ( i.e. displacements of the material through out the 3-D domain), the complete strain tensor field, and the complete stress tensor field. are shown, and we show how dividing a complex problem into smaller problems provided a way to compare the structural stiffness of complex shapes such as jaws.
The following are sample lesson plans based on the Jumping Arboreal Lizard:
