To Do Next Week (decided at 4/7 team meeting)
Laura:
-FEA w/CAD of buckling to verify analytical solution
-FEA and analytical buckling of hollow AL and steel beams
-possible honeycomb inside of beams to ease buckling stresses.
-draw my design with units and give to chris to CAD
Andrew:
-to write list of FEA load cases that need to be analyzed
Chris:
-wants to CAD the final design solution once the team decides what that is.
Daniel:
-post emails from MGM.
-find a manufacturer that makes aluminum.
Jonathan:
-Design ideas
EVERYONE:
-Everyone who is doing FEA analysis needs to talk to Pedro or other FEA expert.
-Laura thinks that group meetings are very productive for brainstorming, and that we should meet more than once per week. Thus far we have been meeting before the professor meetings.
-Daniel has requested 3 CAD files tailored for aluminum, fiberglass, and carbonfiber that can be sent to possible manufacturers, (which design improvements)
-Corrosion due to contact with steel still needs to be researched.
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments
Meeting in-person set up for 5 pm wednesday:
Questions to ask Anson:
What do you think of the hooks that Chris found.
What do you think of making the bottom support beams hollow or honeycombed and either made of steel or aluminum?
What do you think of making the wall either hollow or steel honeycombed aluminum. What about hemisphere's (like a bridge structure) placed inside the beam? Is buckling of the support beams actually relevant or would the beam bend before it buckles?
What about forces in the areas where the beam is not located? What about forces in the places where the beam is not supported by the wheel casters.
What do you think of this or this design solution? (pictures to be drawn before meeting)
for Laura's design: ask Anson if it violates internal dimension requirements.
ask if Laura's design would cause problems because of friction and sliding, and if there is a way to prevent friction that also is ocean-water safe.
knowing that this tub will have parts that will definitely corrode at some point, how can we design this tub so that the parts that corrode are also easily replaceable.
Updates from Last Week Below (in Red)
Review of team meeting before the meeting with Professor Delson + Pedro 3/31 (aka last week):
-Set up meeting with Pedro to help us with CAD. Sample questions: What constraints does the model need? What are the pros/cons of Inventor/Solidworks? Verify the forces and moments are in the right place? How-to know that our model is indeed the "worst-case scenario" ?
Updates:
No meeting set up with Pedro...yet
-Laura's request:
To keep everyone up to date on what new information we have found (and just to keep all information organized and easily accessible to everyone), please write a summary (at least once per week) of what work you did on the ATC project. This would include... 1) What work you. 2) The reason for doing this work. 2) The results of this work. What questions were answered? What new questions/concerns were brought up? What impact does this new information have on our future decisions, etc.
Updates:
???
CAD: Please write summary of the CAD and what numbers/math was used, and what the results were.
Interviews: Please write summary of who was spoken to, what they said, what their name was (if you know), the name of the company, etc.
Design Ideas: Anyone who has a design idea, please put a pic of the idea on the website somewhere, and an explanation of the pros/cons of that idea.
Updates:
Andrew: Did FEA analysis of steel support beams on base of ATC and compared maximum stress before bending (see result in individual component analysis)
Current Gantt Chart:
-Beginning of 3rd week: Have 1st draft of final ATC design due
-End of 3rd week: Have final ATC design due
-End of 4rth week: Finish researching manufacturers and find their approximate time of fabrication for the new ATC.
Updates:
Jonathan: gantt chart updated on friday 4/3
Assigning Roles: There is an interest in assigning leaders of certain roles:
-liaison: Laura
-website updater: ???
-CAD expert: Andrew
-Materials expert: Daniel
-Scheduler (IE someone who reminds us of what stuff is due and when): ???
-Treasurer: ???
Updates:
???
Individual Component Analysis:
Chris: Tie-Down Hook
Daniel: Materials and Manufacturing of fiberglass and carbon fiber.
Laura: Buckling: Analytical and FEA
Andrew: Steel base supports
Jonathan: ???
Updates:
-component analysis was turned in on time
Summary of meeting with Professor Delson and Pedro on 3/31 (aka last week):
On making our designs easy to explain to noobs:
-create a small scaled 3D model of the ATC , both the original version and possible design solutions.
-In the risk reduction presentation, it wasn't obvious from the images on the slides that the lip was what prevented the ATC from being placed onto the airplane.
Updates:
Laura: 3D printed 0.14 scale models of scaffold. Ordered aluminum to make into the body of the ATC.
On CAD Analysis:
-How-To Finite Element Analysis: 1) CAD the existing ATC using fiberglass and/or aluminum. Relevant issues include: Does making the ATC a shell make the model stronger or weaker? Is it better to make the CAD model hollow or solid? Which is the worst-case scenario? 2) Perform fatigue and buckling analysis on the CAD models using the correct forces and moments. 3) Validate these results using some "closed-form" equations from a book, showing the results are similar.
-If the FEA analysis is too short and easy you are probably doing it wrong.
-If the modelling program asks you to shell the model, then perhaps alter the mesh size to get more accuracy (not sure what this meant but hopefully you know Andrew, lol)
Updates:
-decided not to CAD the existing ATC using fiberglass cause we dont want to make the new one out of fiberglass. CAD analysis was conducted using aluminum.
-Making the steel support beams a shell makes them stronger, see Andrew's component analysis.
-Analytical solution of buckling for hollow support beams exists in Roarke on table 9.1 page 311.
-Analytical solutions to buckling on thin walls exists in Roarke with different boundary conditions, see Laura's component analysis.
-Since a hollow model is stronger, the solid model would probly be the worst case scenario.
-Correct forces on CAD model known, but its not known how to implement them correctly as distributed forces in either solidworks or inventor.
-modelling of moments was not researched last week and still needs to be done
-mohamed shama's book on ship structures has nice 3d pictures on what buckling of thin plates looks like with simply supported edges, free edges, clamped edges, etc. found in chapter 11.
On Materials:
-Research how others have analyzed the strength of foam filled fiberglass. If there is an article on this, print it out, highlight the relevant sections, and bring to class.
-There may be books existing that describe how to do FEA analysis on fiberglass. If they exist, find them.
Updates:
-Chris researched the kind of stainless steel for clamps and found what kind is used to be corrosion resistant. (see chris's component analysis for more details)
On Manufacturing Time: !!! important !!!
-It is very important to find out the estimated manufacturing time for the ATC. Don't worry too much that the manufacturer has the exact model, just make sure you get the approximate time of manufacture ASAP.
Updates:
-Quote is acquired but time of fabrication not acquired (from prior manufacturer MGM plastics). Quote: $12k. Made of fiberglass. MGM only does composites, not aluminum.
-Both fiberglass and carbon fiber would use the same mold. molds cost a lot.
-MGM did not give us a quote for carbon fiber based on our existing CAD model because you need a tenth thickness to get the same strength, which would make the price much much cheaper. IE we cant use a universal CAD file, we need a CAD file for each material to get any kind of accurate estimates.