Mission Accomplished

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Looking Back: Frame

1st. We chose 4130 chromoly steel for its weight to strength ratio.

2nd. Built and tested a CAD model.

-We did FEM analysis and it underwent several modifications.

3rd. Building a full scale PVC model.

- It showed improvements we did make to accommodate our largest driver.


4th. Cutting and welding the frame.

- We cut and notched the frame, then created a wooden jig to assemble the frame on. We continued welding until straight through May.


Future recommendations would just be starting early and getting a second TIG welder.

GearBox

When two 53lbs blocks of aluminum and master programmer Luke meet the result, milling greatness.

Final weight about 10lbs.

Design Report

Due April 29.

COMMENT:
We recommend that you bring a printed copy of your design report to the competition and proof of submission.

Closed Cell Foam

Polyethylene Foam

Foam Types: Polyethylene Foam
Standard Sizes: Full, Half
Heights: 1/4", 1/2", 3/4", 1", 1-1/2" and 2"




Features

As closed cell foam sheets or any other form it comes in, polyethylene is a very strong and resilient material which, as one of many types of closed cell foam, is ideally suited for use in many different regards. Some of the most common uses of polyethylene sheets include shock-absorbing, vibration-dampening, insulating, barriers and polyethylene foam roll styles used as buoyancy components. Polyethylene closed cell foam is an excellent material for cushioning products in packaging applications, especially in the form of polyethylene foam sheets . The excellent buoyancy as well as durability of Polyethylene foam allows it to be used in flotation equipment,and other nautical products. Additionally, polyethylene tubes can be used for a number of other purposes, including irrigation tubing and resisting acids and alkalines.

Details

* Closed cell chemically crosslinked polyethylene foam
* Lightweight
* Shatter proof
* Cost-effective
* Easy to fabricate
* Non-dusting
* Excellent buoyancy
* Superb strength, and tear resistance
* High shock absorption
* Flexibility
* Impervious to mildew, mold, rot, and bacteria Superior chemical & grease resistance

Gearing Up

Gear Box - approx CNC mill time 45 hours

Floatation - Steps

1. Rough Shape
2. Contact Cement
3. Attach to skid plate
4. Attach to frame
5. Shape pefectly
6. Heat seal
7. Cover
8. Don't sink!

Frame tabs for seat belt mounts

Next

Tires

Carlisle Tru Power AT 26/12-12

23/8.5-12	$76.25	17	BLK	4	523301
23/10.5-12	$83.98	24	BLK	4	523367
26/12-12	$115.55	35	BLK	8	523360
26/12-12	$104.81	35	BLK	6	523377
26/12-12	$89.47	31	BLK	4	523361

http://stopandgotires.com/modelsize.asp?productcode=523377&src=frgl

and

ITP Mud Lite AT

http://www.mud-throwers.com/inc/sdetail/515

24-11-10	56A305	9/16"	19.5	$77.95
24-8-11	56A332	9/16"	14.2	$69.95
24-8-12	560430	9/16"	18.3	$70.95
24-9-11	56A3A9	9/16"	16.8	$73.95
24-10-11	56A328	9/16"	18.6	$78.95

Final Paper Outline 473/474

COVER PAGE

Title, sponsor, student's names, supervisor,

TABLE OF CONTENT

Sections, page number

EXECUTIVE SUMMARY/ABSTRACT

One page or less, problem, design, approach, results, conclusion

NOMENCLATURE

Optional

INTRODUCTION

Subtitles such as

-Project description

- Motivation

- Background (state-of-the-art)

- Literature search

PROBLEM STATEMENT AND OBJECTIVES

Subtitles such as

- Objectives

- Specifications and requirements for the customer

- Steps taken

- Time table and Gantt chart

DESIGN CONCEPTS

- Design 1,2,3,...

- Evaluation of the concepts the table

- The final design (the winner)

ANALYSIS OF DESIGN

Subsystem and subcomponents are defined global calculations

-Calculation and design of the each subsystem or subcomponent

-Solid modelings

-Finite element modeling and mesh generations, boundary conditions

RESULTS AND DISCUSSION

Results of the FEM and other analysis

Graphs and curves, charts, tables

Discussion of the results

CONCLUSIONS AND RECOMMENDATIONS (Future work)

REFERENCES

APPENDIX

December Finally

Presentation the 8th

Final paper the same week, hopefully.

20th Full(ish) Meeting

Nov.  10 & 12


Fire drill? Electrical short?

FEM and mesh done.
First draft of the report due Tuesday.


Two-part foam kind of cheap, still look for a free sample to test.

18th Full(ish) Meeting

Prototyped a little more.

17th Full(ish) Meeting

We finished the PPT and presented in class.

15th & 16th Meeting

 For Oct. 27 & 29:

Attempted to run a load/stress simulation using Solidworks 2009.

Meeting to finish prototype was scheduled for Oct. 31.

Presentation was outlined.

1. What is a Mini-Baja?
2. What are the major components we must deal with?
3. What is the competition about?
   
4. What have research and and past designs revealed?
5. What were our inital concepts?
6. Why did we chose our current designs?
7. Gantt Chart showing our production goals?
   

14 Ful(ish) Meeting

Did two more pieces of model, we need more PVC pipe.

More talk about design.

13th Full(ish) Meeting

For October 20 2009:

-Watched Brian and Roi  continue to work on the model. Very impressive.
-Some inspector dude came around?

12th Full(ish) Meeting

For October 15 2009:

-Moved the old car into shop.

-Discussed more possible designs.

I'm using Visio 2007 to make the Gantt Chart.

If you have Visio you can go under scheduling >> Gantt Chart

If not you can use Gantt Project at http://www.ganttproject.biz/

Or OpenProj at http://openproj.org/openproj

ConceptualDesigns1

CCNY Mini Baja

Conceptual Designs

Prof. Sadegh

ME 47300/2PR

Introduction

The Society of Automotive Engineers (SAE) in conjunction with various colleges and automotive companies hosts a Mini-Baja competition event. The event involves building a Mini-Baja off-road vehicle, testing it, and then racing it in five to six events. Although there are strict rules set by SAE there is enough room to make our design unique.

This project has many parts but in the initial concept phase we focused on six main parts:

1. Frame
2. Front Suspension
3. Rear Suspension
4. Rear Steering
5. Drive Train
6. Floatation

The frame is the most important part of the design since it must be sturdy enough to survive the abuse of the racecourse. It must also conform to the latest SAE rules and fit all the components that will make the off-road vehicle run. An evaluation matrix was drawn up where the higher the score means the better the concept.

Frame

              We made a rough estimate of we believed to the most important points when making and assembly the frame. Thinking about straight tubes with gussets or bent tubing as a group we were split evenly. The matrix did not help as much as we would hope. We are leaning towards the bent tubing because the manufacturing would be simpler and we need to manage our time efficiently.

Frame/Joints		Straight W/ Gusset		Bent Tubing
	Weight	Rating	Score	Rating	Score
Manufacturability	3	3	9	4	12
Weight	4	3	12	4	16
Durability	5	4	20	3	15
Component Protection	3	4	12	4	12
Safety	5	4	20	4	20
Cost	1	4	4	2	2
Adjustability	4	3	12	3	12
			89		89

              To see how the bent tubing would look we made two frames. Design A is more complex but offers a stronger design and would not need any gussets.  Design B is simpler and adding gussets would be possible.

Figure 1: Frame design A and B.

Figure 2: Side view of Design A.

              Since we are leaning towards the first design, it is the one we choose to build it out of PVC as a full-scale model. We started building the model at the SAE shop on Tuesday and it should be done soon and the final design will be chosen.

                         Figure 3: Deign A dimensioned.

Front Suspension

              Having done the double A arm in the past wear attempting to make an short-long arm (SLA) this time around since it would be better in cambering. The two designs show little differences overall.

Front Suspension		Double A Arm		SLA
	Weight	Rating	Score	Rating	Score
Manufacturability	3	3	9	2	6
Unsprung Weight	4	4	16	4	16
Durability	5	4	20	4	20
Component Protection	3	2	6	2	6
Cambering Effects	4	3	12	5	20
Cost	5	3	15	3	15
Adjustability*	4	0	0	0	0
* could not verify yet			78		83

Rear Suspension

              For the rear suspension we tried to think of all the possibilities to gain an edge on power, maneuverability, and durability during the race. The swing arm would not work well with rear steering due to independent movements of the arms. The multilink is something we feel would work well but we have little experience and we are testing that and the swing arm in Solidworks, Figure 4 & 5.

Rear Suspension		Double A Arm		Swing Arm		Multilink
	Weight	Rating	Score	Rating	Score	Rating	Score
Manufacturability	3	3	9	1	3	3	9
Unsprung Weight	4	4	16	2	8	4	16
Durability	5	4	20	3	15	4	20
Component Protection	3	2	6	3	9	3	9
Cambering Effects	3	3	9	0	0	5	15
Cost	1	3	3	1	1	4	4
Adjustability*	4	0	0	0	0	0	0
* could not verify yet			63		36		73

Figure 4: Design B with swing arms on rear and double A arms on the front.

Figure 5: Deign B with multilink on the rear and double A arms on the front.

Rear Steering

              Rear steering was also highly debated but we ended up going for the mechanical steering since the servo tend to be less reliable and less durable in extreme conditions. We expect this vehicle to be subjected to a harsh environment and violent shaking.

Rear Steering		Servo		Mechanical
	Weight	Rating	Score	Rating	Score
Reliability	5	4	20	5	25
Weight	1	4	4	4	4
Durability	5	3	15	5	25
Component Protection	3	4	12	3	9
Cost	3	4	12	2	6
Adjustability	2	5	10	2	4
			73		73

Drive Train

              Again, due to the expected harsh conditions a chain would prove to be more troublesome. We all have more experience with gears but we are still open to the idea of a chain if an inexpensive and large enough change can be found.

Drive Train		Chain		Gearbox
	Weight	Rating	Score	Rating	Score
Manufacturability	3	5	15	3	9
Weight	4	3	12	5	20
Durability	5	3	15	5	25
Component Protection	3	3	9	5	15
Reliability	5	2	10	4	20
Cost	1	5	5	3	3
Adjustability	4	1	4	1	4
			70		96

Floatation

              Part of the competition involves going on to a lake turning around and driving out, without sinking of course. This part would be one of the last things done to the Mini-Baja car but it is critical since flooding will cause considerable damage to the rest of the systems. Closed cell foam is more versatile and less bulky. We saw other Mini-Bajas that use wood but they are not as appealing. Part of the water competition involves a timed trial to get in and out of the car safely. We believe the giant wood block may interfere with this challenge.

Floatation		Wood		Closed Cell Foam
	Weight	Rating	Score	Rating	Score
Manufacturability	3	4	12	1	3
Weight	5	2	10	4	20
Durability	5	4	20	2	10
Component Protection	3	3	9	3	9
Effectiveness	5	2	10	4	20
Cost	1	3	3	2	2
Adjustability	4	3	12	4	16
Appearance	1	2	2	4	4
			78		84

Conclusion

              Each member of the group has their own section of the vehicle they will focus on and we are relying on their expertise to explain their choices.  The current choice is a bent frame design with SLA in the front and a multilink on the back. The steering will be controlled mechanically and a gearbox will be used. The floatation will be done using closed cell foam.

              Even though we are fairly set with our designs we are still open to change since most of the choices were very close in scoring. Some of the design elements like floatation are dependent on the size, shape, and weight of the overall vehicle so these will be fine tuned as the vehicle is built.

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