Flight Mission Challenge: Improving Earthquake Monitoring Educator’s Guide with Activities in Science, Technology, Engineering, and Mathematics Grades 5-9 Acknowledgements
Shaky Table Construction Directions
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- Navigate this page:
- PART I: Base of Earthquake Table
- PART II: The Shake Platform
- PART III: The Drill Mechanism
- Constructing the Box Assembly Step 1
- Part IV: Crank Mechanism
Shaky Table Construction Directions2 These instructions describe how to build an inexpensive shake table to simulate ground motion during an earthquake. The table is ideal for having students design Popsicle stick buildings to minimize damage during an earthquake. The table is also an excellent mechanism to study the resonance frequencies of buildings using the BOSS (Building Oscillation Seismic Simulation) Model published by AGU/Fema in their Seismic Sleuths publication. PART I: Base of Earthquake Table Materials Needed:
Note: All ceiling hooks and carriage bolts are centered on the 2 x 4 lengths. Step 1: Attach 2 x 4s to 20” x 40” plywood piece using drywall screws (Fig. 1). Carriage bolts are attached to the inside 46” length 2 x 4 at distances of 10.5”, 13.5”, 22.5” and 25.5” from the end that extends beyond the plywood base and should be countersunk to allow the 2 x 4s to lie flat on a countertop. Use ¼” nuts to secure carriage bolts. (Fig 2). Place rubber sleeves over carriage bolts to prevent wear on wooden dowels. 
Fig. 1: Underside of base 
Fig. 2: Installing Carriage bolts & PVC tracks Step 2: Prepare to attach PVC pipe by first drilling three holes in the PVC. Two should be located 2” from each end and one at the midpoint of the pipe. These holes should only be drilled through one side of the PVC pipe. They will allow you to secure the pipe to the base later by serving as “windows” for the screws. These holes help the platform to glide more smoothly than if screws were sticking up a little on the top of the PVC pipe. Again center the pipes on the outer 2 x 4 and inset 2” from each of plywood sheet (Fig. 2). Step 3: Ceiling hooks are attached to the inner 2 x 4 at distances of 3” and 33” measured from the end that extends beyond the plywood base (Fig. 3). 
Fig 3: Base Section Ceiling Hooks installed Step 4: After assembling the base of the table, split each of the four 7/8” PVC pipe sections lengthwise and place one on each end of the wooden dowels (note: stretch open each section of PVC carefully to fit over the ends of the dowels). These dowels should be placed inside the bolt “fences”. Do not secure these dowels! They will be the part that the shake table platform will move back and forth on (Fig. 4).  
Fig 4: Dowel placement on base and PVC section installation PART II: The Shake Platform Materials Needed:
Step 1: Attach the two 2 x 4s to the edges of the plywood with drywall screws and place the ceiling hooks 5” in from the edge of the plywood and centered on the 2 x 4s (Fig. 5). Apply paint and/or logos as builder’s discretion. The optional Plexiglas cover for the platform may be used to etch in scaling values or as protection for painted logos, as desired. Attach Plexiglas with 4 or more 10 x ¾” wood screws. Note: Use caution when drilling holes in Plexiglas due to shattering.  
Fig 5: Platform assembly with ceiling hooks installed Step 2: After assembly is complete, the table should be secured on top of the base by hooking 2 to 3 large rubber bands around each pair of hooks. The table platform should be able to roll back and forth over the wooden dowels (Fig. 6). 
Fig 6: Platform installed on base and secured with large rubber bands Step 3: Cut one ½” length off of each Velcro strap and set aside. Attach one end of a 29” Velcro strap to the edge of the platform lateral axis using one 10 x ¾” pan head screw. Using a small piece of Velcro, attach to the opposite edge of the platform using two self-tapping pan head wood screws. Repeat Velcro attachment process for longitudinal axis.  
Fig 7: Velcro attachment PART III: The Drill Mechanism Materials Needed:
Constructing the Box Assembly Step 1: Cut a 7” x 11” piece of ½” plywood and attach to the corner of the base (opposite of the platform assembly) using drywall screws. Step 2: Construct the walls of the box and attach to box base using corner brackets (Fig. 8). Note an additional 1 ¾” x 7” x ½” strip of wood is used to reinforce each short side of the box. 
Fig 8: Box Assembly with end walls attached Step 3: Attach a 1 ¾” x 11” x ½” strip of wood along the inside edge of the box to enclose three sides of the box. Attach a 7” x 11” x ½” plywood sheet to the top of the box using drywall screws to complete the box assembly (Fig 9). 
Fig 9: Completed box assembly Step 4: Attach the 6” length of 2 x 4 with the 5/16” hole (1.5” from top of 2 x 4) using drywall screws and corner brackets (Fig. 10). Attach the electric drill using the carriage bolts with wing nuts and the metal strap as shown in Figure 11. Note: Use Styrofoam or similar material between the drill and box assembly to adjust alignment of crank mechanism. 
Fig 10: Crank support and drill tie-down strap attached to box assembly 
Fig 11: Drill mounted with strap Part IV: Crank Mechanism Materials Needed:
Step 1: Assemble the crank mechanism using Figures 12 - 14 as a guide. Drill one 5/8” hole on one end of the 2 ½” steel bar approximately ¼” to ½” from the end and tap and thread for securing to the main drive (3 ½” length) 5/8” hex bolt. Drill a 3/8” second hole approximately 1” from the main drive hole and tap and thread for securing the 3/8” armature bolt. See figure 12 for general arrangement of crank and armature assemblies. 
Fig 12: Crank and armature mechanisms Step 2: Drill one 3/8” hole on one end of the 15” steel bar approximately ¼” to ½” from the end. Drill a 3/8” second hole approximately ¼” to ½” from the opposite end of the 15” steel bar. Using a vise and large crescent wrench, twist the mid-point of the 15” steel bar to create a 90o twist in the armature. Figure 13 depicts the twist in the armature desired for attaching the crank assembly to the table’s platform assembly. 
Fig 13: Assembled unit showing 90 deg. twist in armature Step 3: Temporarily remove the crank support block from the box assembly and insert the two 5/8” bushings into each side of the 5/8” hole drilled through the crank support block. Drill out the inner threads of the bushings to allow the 5/8” main drive hex bolt to turn freely, then reattach the crank support block back onto the box assembly. Step 4: Using a hammer and punch set, tap down the sharp anchors on the two 3/8” bushings. If desired, the sharp anchors may also be removed by a grinder using standard shop practices. Drill out the inside threads of both bushings and set aside for later assembly. Step 5: Place one washer onto the main drive hex bolt and attach the threaded 5/8” end of the 2 ½” long steel bar to the main drive hex bolt. Tighten bar onto main drive hex bolt, then add 58” nut to backside of main drive crank assembly to ensure tight fit. Additional washers may be required to obtain correct alignment of the main drive crank assembly with the armature assembly. Refer to figure 14 for configuration. 
Fig 14: Assembled main drive and armature mechanism Step 6: Place one washer onto 3/8” x 2” armature bolt and insert into 3/8” hole in the main drive crank assembly and tighten. Install a 3/8” hex nut, and tighten. Insert one washer, followed by one of the previously prepare 3/8” bushings, and place one end of the armature bar over the bushing, ensuring that it does not bind. Place another washer onto the armature hex bolt and complete the assembly by installing a 3/8” lock washer. Tighten assembly and ensure that the armature does not bind on the crank assembly. Refer to figure 11 for configuration. Additional washers may be required to adjust alignment of the crank mechanism. Step 7: Place the armature onto the top of the installed platform assembly, mark the spot where the hole in the armature rests on the platform and drill a 3/8” hole in the table’s platform. Insert the 3/8” x 2” bolt up through the bottom of the platform hole using a washer, followed by a 3/8” bushing (mounted flat side to top of platform). Attach the end of the armature over the bushing, then install a washer and complete with a 3/8” lock washer. See figure 15 for configuration. 
Fig 15: Armature attached to platform assembly Step 8: Lock hex bolt in electric drill and operate slowly for the first time to evaluate alignment of crank and armature mechanism and adjust as needed. Periodically check all assemblies during operation for tightness and wear. --------------------------------------------------------------------------------------------------------------------- Figure 16 depicts the final product (Note: disk crank assembly was replaced with more robust steel bar crank assembly in current revision) for reference. When using the shake table, secure it to the table it is resting on using clamps. This will prevent the shake table from walking when the drill is operating at higher RPMs. Use caution when operating shake table above 300 rpm as possible damage to the crank mechanism may occur. Expect to pay approximately $50 to $100 for a good drill. The rest of the materials should not exceed $50. The steel crank and armature components may require some machine time and this cost will vary. Therefore, Labor charges have not been calculated. 
Fig 16: Final Shake Table assembly (with superseded disk crank assembly) 1 This section is excerpted from Plan to Fly There, Aeronautics Educator Guide (NASA). 2 Original Design by Casey Hagbo, Geophysics Major, Class of 2001. Modified by NASA AREE Team, 2010. Directory: resources resources -> General text for tender (recommendations) for Pilkington Profilit™ Contents Page resources -> North Carolina Inclusion Initiative Mapping Where Children with ieps are Being Served Purpose resources -> Practice learning resources -> The Rise of Video Games Section “Word” Matt Spencer resources -> Request for proposal contract form for the transit industry resources -> Request for Proposal [insert date] resources -> The University of York 13th 16th April 2004 resources -> Biological and Biomedical Sciences Program Community Education Initiative resources -> Region III standing regional response team (rrt) meeting williamsburg, Virginia Thursday, January 12, 2012 resources -> Efca eastern District and TouchGlobal, the crisis response ministry of efca Download 0.76 Mb. Share with your friends:
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