Carnegie Mellon Mechanical Engineering

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FEM/ANSYS ## Test S3: Analysis of 3D Solid      Structural Test #3: Analysis of a 3D solid object

Introduction: In this test problem you will be required to test your knowledge of 3D modeling and the Solid element in ANSYS.

Physical Problem: One day while using his hammer, Professor Shimada attempts to drive a nail into the floor of his home.  Unbenounced to him a layer of pure steel had been installed under the wooden floor.  The nail doesn’t move and so a point force of 100N is exerted on the head of the hammer.  Plot the nodal solution of the deformation and stresses on the hammer.

Problem Description: We will model the object using solid Tetrahedral 10 node element. Material: Assume the structure is made of steel with modulus of elasticity E=200 GPa and a Poison’s Ratio of 0.3. Boundary conditions: The hammer is fixed at the base..  Objective: To plot deformed shape. To determine the principal stress and the von Mises stress. (Use the stress plots to determine these. Do not print the stress list) What is the maximum load the object can take. Clearly mention the yield stress that you have assumed for steel. Also assume factor of safety of 1.25. You are required to hand in print outs for the above. Figure:   Dimensions:

10 cm hexagonal handle, radius 0.02m, theta=300 at (0,0)

15 cm circular solid, radius 0.015m at 0,0) Create the hexagonal solid defining the grip for the handle. Shift the workplane the axial length of the hexagonal solid and create the circular solid defining the section between the handle and the head of the hammer. Shift the workplane again and create the hexagonal head of the hammer. Now rotate the workplane and shift it such that the cone is created 0.09m in the correct direction from the axial center of the handle. Now overlap the conic section and the hexagonal volume defining the head of the hammer.  Once these are married into one volume, add the volumes together such that the hammer is one full volume. Define the Material Properties of the Steel hammer (Elastic Modulus and Poison’s Ration are the important qualities) Define the Element Properties as a Tet 10 node Structural Solid. Mesh the hammer. (Do so by picking all lines and setting the element edge length to 0.01.) Apply the boundary conditions. (Structrual Displacement on the bottom face of the handle equal to zero, and a structural force / moment on a node closest to the center of the hammer head as possible equal to 100N in the X direction.  If the hammer head is oriented properly then this value should be directed perpendicularly into the face of the hammer’s head.) Solve List the nodal results of the solution with respect to all degrees of freedom. Plot the nodal solution with respect to all degrees of freedom. Show both the deformed and undeformed shape of the hammer.

(The output should be identical to the figure below) (Without the Undeformed Hammer it should look like this:) (Select a stress (say von Mises) to be plotted and click OK.  The output will look like this.)  