Overall Completion

This is our final product of the physical model of our Engineering Design Laboratory Project. The main challenge of creating the model is making the precise cuts for each part and using wood glue to piece it altogether. It is not an exact replica of the Canadian National Tower but a representation of it. Steven, was in charge of making the physical model during the last week since he's more experienced with making applicable cuts with wood. Linh Al was in charge of finishing up the CAD model and Visual Analysis results which is all located in the final report. Michael and Yuan focused on writing up the presentation and putting the finishing touches to the final report. Now we're ready for our presentation ! 

New Parts for Physical Model

For the physical model, we have constructed the hexagonal base and the four caissons which is the primary foundation for the CN Tower. We went to the wood shop and utilized their tools to make the right parts for the tower.

For this week's assignment, we had to mainly focus on making the parts of the physical model and fixing up the Visual Analysis Model. From the previous post of our blog, Island was in charge of fixing the Visual Analysis Model so that it would not fall apart anymore while applying loads to it. Yuan is currently fixing up the Final report for grading in week 10, Michael updates the blog by posting about current progression, and Steven works on the physical model of the tower.

Here are some pictures of the parts we made at the wood shop :

We needed to sand down the sides of the 360 restaurant to make the slants of the part.

This is a picture of the primary parts of the foundation for the tower. There's a hexagonal base below the tower and above the 4 caissons for a strong foundation.

A picture of how the foundation will look like under the tower when all put together.

The main difficulty this week was having the correct visual analysis model because of importing different parts from Creo Parametric. The only solution was to make the tower as a whole and it was correctly shown in the result view. Also, since we don't have considerable experience with the wood shop, some measurements of the parts were inaccurate. We did our best to make the precise cuts that corresponded with the scaled down measurements of the tower. 

Update On Visual Analysis

Last week, we discussed that there were problems involving importing the revolving restaurant portion of the CN Tower to Visual Analysis. There was also another problem that occurred when going onto result view. We realized that importing an assembly would cause the tower to fall apart because an assembly is just a bunch of parts connected together. We tried to fix this by changing deleting nodes and changing around members, however that proved to be tedious and inefficient. Examples of what we tried to do can be seen in figure 1 and 2.

figure 1: The circled nodes were deleted and replace with just one node.

Figure 2: The nodes were replace and a new member was made to represent connectivity between parts

We decided to create a new 3D CAD model, specifically made to import to Visual Analysis. This time the whole CN Tower would be made into one part, meaning no assembly. This way there would be no parts falling when the model is imported into Visual Analysis. The new part consisted of a new, more simplified version of the revolving restaurant, as shown in figure 3. 

Figure 3: New revolving resturant. 

It was successfully imported to Visual Analysis with surprising no problems at all! The new revolving restaurant did not affect the stiffness matrix of the tower, and no parts fell apart, as the whole CAD model was just one part. Figure 4 shows that the tower functions properly in Visual Analysis, and all the parts of the CN Tower moving as one. 

Figure 4: Result view of new imported CN Tower CAD model

Load analysis will be under way! We predict to finish sometimes this week. 

Physical Model Progress

For this week's goal in terms of the Physical Model of the CN Tower was to construct the pod , the revolving restaurant. Since the wood materials are not thick enough to make the whole pod, we cut out two circular pieces from the wood.

Using the extra piece of wood we had, the wood material of the revolving restaurant was cut out like this. 

These two pieces will then be glued together in order to make the revolving restaurant. However, we still need to make a bigger hole of these circular pieces so it can fit with the shaft of the tower. The difficult process will be making the restaurant actually revolve, which means that we will have to lathe the shaft. So far, the physical model looks like the following : 

Update on Visual Analysis

This week was focused on finding the error that occurred when importing the 3D computer model into Visual Analysis. Finding the error in the whole 3D model proved to be impossible. Each part of the computer model was imported into Visual Analysis and examined one at a time. Once imported, the parts were pinned to the bottom to see if they were structurally sound.

We found out that the error only occurred with the top portion of the tower. The revolving restaurant and above displayed several errors in the result view.

Afterwards, each part that did work was assembled together one part at a time and imported to Visual Analysis to see if there was any problems that occurred with importing assemblies of the parts into Visual Analysis. The result view was displayed, even after all the whole assembly of the tower, with the exception of the top, imported.

However, one thing was realized once the result view displayed. Visual Analysis did not see the 3D model as one part, except several different parts.

As shown in this picture, one of the wings falls off in the result view.

Draft for Final Proposal

https://docs.google.com/file/d/0ByKCbu-_5kaBMUtvN29tZ1dnYWM/view

To view the PDF file of our draft of the Final Proposal, look at the above link.

The remaining work we will be doing is focusing on making the physical model and analyzing the Visual Analysis model of the tower.

Wings Constructed !

After Engineering Design Laboratory class, we went to cut out our wings from the piece of wood with the drawings. The pictures above is a good idea of how the CN Tower will look like with the constructed wings. The next thing we will work on for the tower is the core and the pod. 

Visual Analysis Progress

After making the 3d model in Creo Parametric , we were able to save the model file as a DXF file which could be imported into Visual Analysis. Since the visual analysis programs provided were educational/student versions, we needed to download the 30 days free trial version that would be able to important DXF files. 

Importing the Creo DFX file into VA

After importing the DXF file into the Visual Analysis Free Trial program, nodes were selected to be either pinned, free, or fixed from the modifying tab. 

Core caisson of the tower

The circular motion symbol means that the nodes are fixed, meaning that it would be extremely difficult to move in terms of rotating and translating. All four of the caissons' nodes were fixed since they are the foundation of the tower which cannot move at all.

Concrete base with other caissons

The circle symbol means that the nodes are pinned, meaning that it can't translate but it has the ability to rotate. We made the concrete hexagonal base to be pinned on all nodes because it's not deep enough into the ground level and it could still rotate. 

The goal was to learn how to use the Visual Analysis program and to be able to import our Creo Parametric file into the program. With a little bit of guidance, we were finally able to do so. From there on after watching Visual analysis tutorials, we were able to fix the nodes to be pinned, free, and fixed. 

Now we can mess around with the program a little bit to make a better analysis model of the CN Tower. 

Ultimately, we're aiming for a result view of the tower's gravity loading and air resistance. 

(We're still working on that part)

Making Blueprints for the Wings of the CN Tower

The goals for this week was to make the wings of the CN Tower, which is the hardest part to make because of the wing's curve/bulge. The challenges for making these wings was making the radius part of the CN Tower's wings.

Setting the radius of the Wings

After scaling down the measurements from the actual CN Tower, we found the radius to be about 8-9 feet. So we used a 8-9 ethernet cable to draw the wings by stretching it out and moving it in a circular motion on the piece of wood where the wings were to be constructed. Stretching out the ethernet cable and moving it in circular motion was my role, Michael.

Making Measurements of the Wings

We were able to draw an accurate curve of the CN Tower, and put it up against the shaft to make sure it looked correct. At this point, we had only drawn one wing on one side of the wood. The wing's peak is .17 inches and the base is 1.75 inches. Drawing the part of the wing was Steven's role.

Making a Wing from Paper

Instead of using the ethernet cable to continually draw the other wings, we found a easier method which was to just make a wing out of paper and start tracing three wings on the wood which was Yuan's role.

Starting to trace the wings for the wood

Some of the drawing may be inaccurate due to inaccurate tracing. The other side of the wood's drawings may also not correlate with the current side being worked on. The solution to this was to use the paper as a straightedge and fold it on both sides to see if the wings can correlate with each other.

Completed Drawings of the bridge

These are the 3 completed drawings of the wings for the CN Tower. We tried to use a small handsaw in order to cut the wings out but it was proved to be difficult so going to the wood shop will be a better method to make precise cuts. If we used a regular jigsaw, the cuts could be inaccurate, especially if cutting the radius part of the wings. Island's working on the Visual Analysis model and still watching tutorials to learn more about the program. 

Current Progression

We have recently learned how to add percent completion to the project libre project. Here is the current picture of the timeline in gantt chart.

Due to some setback, from the gathering of materials to getting space at the woodshop, we are set back a week.
So far, we are 25% done the physical model, and plan to do the visual analysis this week.

Completed 3D Model

For this week's assignment we needed to complete the 3d model of the CN Tower and research on the foundation of the CN Tower.

Creo Parametric Models :

 This is how the CN Tower mainly looks like with an antenna, 360 revolving restaurant, glass elevator, three wings, and the foundation of caissons.

Dimensions of the Antenna, top part of the CN Tower. The base of the sketching is the radius of the antenna. This part of the CN Tower was configured by adding extrusion and protrusion.

 The research for the foundation of the CN Tower was difficult but a primary source such as Engineering-News Record provided sufficient information. "The tower is anchored by four 30-in dia caissons drilled through 30 ft of earth overburden and as much as 90 ft into shale and one caisson drilled to 350 ft.

 
 
The base, wings, and 360 revolving part of the CN Tower was all made with protrusions and extrusions just like the antenna. The assembly of the model looked like this :

The dimensions are based on a Sketch Up drawing which served as our primary source to make the 3D model.

The main challenges in making the 3D model was not having the right dimensions before making this model. The previous model was completely based on researched dimensions off the web. However, the Sketch Up image gave the right dimensions. While assembling the parts in Creo Parametric, some of them did not constraint together correctly. We went through basic trial and error to solve the problem. When creating the wings of the tower to be constraint to the tower, one of them were not inverted correctly when modifying the radius to curve the wing. The solution to this problem was to create the same part with the same dimensions but this time, it was flipped from the vertical axis. 

For this week's assignment, it was important to learn the main foundation of the CN Tower which is essential to our physical model of the tower. It was hard to understand the Creo Parametric tools to create the bulge of the wings. With some basic research and tutorials, everything started to come together. It was fun making parts of the bridge and being able to put it together as everyone put in team effort. 

We have finally gathered all the materials for the CN Tower. We will be working on the physical model this week at the wood shop. 

Gathered Materials

At this point we have gathered some materials to make the physical model which is the motor with wires that could represent the 360 restaurant of the tower, LED lights that could surround the motor, and the syringe to represent the antenna of the tower. For the rest of the model, we will be using wood which will later be obtained from a hardware shop around Drexel University.

Use of Visual Analysis

To model the Canadian National Tower, the use of Visual Analysis is required to define the foundations of the tower such as the weight loads, visual images of how the tower is affected from weight loads, and modifying certain members. For this week, a visual analysis problem was given to us to gain a better understanding of how to use Visual Analysis. The following picture is what we had to analyze :

After putting this Visual Analysis file into the program, a result/report view reported the problem was that "A negative stiffness diagonal  has been found at node: 022 Z-Translation Check your model for stability problems near this location." The solution to this problem was to adjust the nodes, add a few members, and make some points fixed and free.

The first revision was done by implementing a type of Pratt Truss because during the Bridge Design in Engineering Design Laboratory, it was found to be the strongest truss out of the main three of Howe, Pratt, and Warren. After making these modifications, the same problem was still occurring with negative stiffness diagonals. Some adjustments were applied to the vertical part of the bridge to eliminate these problems.

The result/report view was displayed correctly without any further problems. The left picture is the newly modified version and the right picture is the correctly displayed result view. 

Visual Analysis techniques were learned thanks to watching some tutorials and making several modifications to the assignment. It was difficult modifying some of the nodes and members because of the snap modes. It was fun messing around with the members to test how the bridge would bend and pushed to the ground. It was annoying constantly dealing with the problem of negative stiffness. 

The main challenge right now is finding the right 3D rendering program to make a 3D model of the CN Tower that would work along side with Visual Analysis. Right now we are still using Creo Parametric for the model.

Week 2 3-D Model Progress

This is our 3-D of the CN Tower so far. The base of the tower looks wider than normal. The challenge while making the 3D model was the diameters of the tower were being estimated. The dimensions of the tower could not be found. The model will be updated alongside with the visual analysis model.

All the parts were made from extruded protrusion and revolved protrusion in Creo Parametric.

The design for the 360 restaurant came from this image:

The Antenna design came from this image:

Both images came from : http://en.wikipedia.org/wiki/CN_Tower

Gathered Information

General Information about the Canadian National Tower

The CN Tower started its construction in February 6, 1973.

It was opened to the public on June 26, 1976.

It costed $63 million to build the CN Tower.

The tower stands at 553.33 meters (World's tallest tower from 1976-2010)

The world's highest wine cellar at 351 meters above ground.

Holds over 500 events every year and has 2 million annual international visitors.

LED system to signify the date (ie. red for world AIDS day).

The foundation is 6.71 meters deep with over 7000 cubic meters of concrete and 500 tons of steel.
The antenna was in 44 parts, before assembled.

Updated Timeline

Using ProjectLibre to make a timeline. Subject to change.

Proposed Idea for ENGR 103 - The CN Tower

Engineering Design Laboratory III

Faculty Member : Emin Aktan

Teaching Fellow : Ben Cohen

Title : Dissecting Constructed Systems

Theme : Infrastructure

Topic : The structure that we will be working on is the CN Tower.

Some Description : 

This Canadian National Tower is located in Toronto, Ontario, Canada. 

The height from the bottom to the top of the antenna spire is 553.33 meters.
Serve as center of communication in Toronto.

Expected Timeline of Project