Design and Construction of a Mini-Baja Vehicle

Document Sample
Design and Construction of a Mini-Baja Vehicle Powered By Docstoc
					Design and Construction of a Mini-Baja Vehicle
     ME 416 Mechanical Engineering Design II
            Professor Siva Thangam

                Mark Cambria
               Robert Kasegrande
                 Michael Nagle
                 Chris Wilson

         Advisor: Professor Gilbert Wray
“We pledge our honor that we have abided by the Stevens Honor System.”




               Mark Cambria

               Rob Kasegrande

               Michael T. Nagle

               Chris Wilson
                                        Abstract

       This project proposal entails the design of a Society of Automotive Engineers

Mini-Baja Vehicle, which will be entered in a national competition. In this report, the

team describes the project scheduling, task assignments and cost analysis to complete this

project in a small time frame. This project is a continuation project of ME 415, in which,

the design of the vehicle was presented. It is the goal of the design team to successfully

compete in the Mid-West Mini Baja competition. The design team feels this will provide

each member with a broad engineering experience, involving, design, project scheduling

and manufacturing, as well as, showing Stevens’ excellence in national design

competition.

       Presented within this report are the teams Statement of Work, Project Description,

Task Breakdown, Cost Analysis, Time Frame and Design Drawings of previously

designed components. The key to this project, as in most projects, is overall cost. The

design team estimates four separate costs over the entire project time frame. These costs

are materials, labor, traveling expenses for the competition and overhead. Totally these

four costs is approximately $5,086.51. However, since this design is proposed to an

educational, non-profit organization, the team will only experience the cost due to

materials and traveling expenses. It is our estimation that approximately $2,618.51 will

be needed to successfully complete this project.
                                    Statement of Work

       The design team set forth in the first semester to make design modifications to an

existing Mini-Baja vehicle. This semester the team will fabricate a vehicle to be entered

into the Society of Automotive Engineers Midwest Mini-Baja Competition in Milwaukee.

Project scheduling is of extreme importance to meet the goal of the team.           Proper

scheduling will allow the team to organize an coordinate an engineering project in a

professional manner.

       The team has broken the spring semester’s projects into various categories,

utilizing the time that is available. The obstacles that are set before the design team can

be negotiated fairly simply with proper time management.            First, the team must

disassemble the existing vehicle so that proper repairs can be made. Salvaging all

components which will be replaced is a major importance to the team. During the time of

disassembly, the team has decided it would be beneficial to work on the SAE competition

report. The Society of Automotive Engineers requires that each team submits a finalized

design report, including all assembly engineering and assembly drawings, along with an

accurate cost analysis.     The team will also be responsible for ordering all new

components and raw materials needed to complete the vehicle. The team is expecting to

be confronted with time delays, therefore, the utilizing the beginning of the semester is

very crucial to complete all of the project’s tasks.

       Once the design team has received all of the required raw materials, the

machining of parts will begin. It is anticipated that obtaining machine shop time will be

difficult, therefore time management is very important. Each member of the team will be
designated to a certain component, this will help to utilize each of the members time

more efficiently.

       It is apparent to the design team that during the disassembly of the vehicle, that

the group may encounter more design problems which were not visible in the first

semester. Hence, leading to the team decision to perform the disassembly of the vehicle

early in the semester, allowing time for proper design alterations to be made.

       The first phase of the two semester design project allowed the design team to

make use of the design theory acquired in school, while the second phase will allow the

team to encounter a more hands-on engineering experience. Dealing with vendors, time

lines, and financial decisions will give each of the members experience preparing them

for real world situations.
                                     Introduction

       During the fall semester the team presented a finalized design of a Mini-Baja

vehicle. The design is being proposed for construction in the spring semester. The goal

of the team was to enter a competitive vehicle in the Society of Automotive Engineers

Midwest Mini-Baja competition.      Previous senior design groups have made many

attempts to perform the project at hand. Dependent on the size of the design group, the

groups would either deliver a complete vehicle design or perhaps a modification of an

existing Mini-Baja.   Each of these projects provided the team members with great

automotive design experience. The groups gained experience in the way a manufacturing

industry is handled, dealing with vendors and machine shop time restraints. Basically,

providing the members with a well rounded engineering design experience.

       The design of Mini-Baja vehicles has become a very large industry. The industry

stretches a very broad spectrum from heavy off-road competition to recreational use. The

proposed spring semester project will allow the design team to utilize state of the art

technology to maximize the performance of the design modifications. However, the

design will be limited to the rules and regulations of the Society of Automotive

Engineers.
                                   Project Description

       The overall goal for the project is to construct and assemble each of the previously

designed parts. The major tasks that must be completed for the project are disassembly of

the current vehicle, machining and assembly of the engine mount, machining and

assembly of the hitch mount, installation of suspension system, installation of rotors and

braking components, improved vehicle aesthetics, and various safety features. Once all

of the major tasks are completed, the vehicle will properly be tested in order to maximize

the teams performance in the SAE competition.

Disassembly:

       The existing vehicle is going to be disassembled by the members, salvaging all

vehicle components which can be reused. Disassembly will occur in the beginning of the

semester allowing for any corrections to the new design to be performed. Performing

various tests on the vehicle’s existing parts to ensure they meet the SAE safety

regulations will be conducted. Though the team will be provided with a new Briggs and

Stratton Engine, it will be necessary to run tests to determine if the vehicles kill switch

was wired properly. Also, just to improve the condition of the engine to be used for by

the school’s SAE chapter, the team will also perform basic maintenance checks on the old

Briggs and Stratton Engine.

Ordering Components:

       It is very important that all components are ordered early into the project in case

of back ordering or any other ordering delays (i.e. UPS Strike). The components not only

include finished products, but also raw materials for machining. Once these materials are
received, it will be very important for the team to schedule machine shop time. The team

is estimating a total of approximately 15 hours of required machine shop time.

Engine Mount:

       The assembly of the new engine mount design requires machining new parts. The

new design consists of new cross beam added to the tubular frame of the existing vehicle.

This new cross member is connected to a previous cross member by two support beams,

14” long and 0.5” square. The engine is then mounted to a plate 0.5” thick, 6” wide and

9” long. The steel used for the support beams and plate is ASTM A-36 steel. The

fabrication of this engine mount will begin the new member being machined at the

Stevens Machine Shop. After this is completed, these parts will be assembled to the

vehicle using welds.

Suspension System:

       The newly designed suspension system consists of standardized parts and

additional machined parts.    New shocks and springs will be ordered to meet the

specifications from our design. The spring constants for the rear suspensions were

calculated to be k = 61.9 kN/m and k = 53.761 kN/m for the front suspension. A new

mounting bracket was part of our design. This bracket consists of two plates that are

welded to the suspension member and serve as a variable shock mount. They adjust the

shock angle and position in relation to the suspension arm. Once materials have arrived,

these plates will be machined at the Stevens Machine shop.
Braking System:

       The braking system was a major feature that was redesigned during the first

semester of the project. The team has designed a system which requires new rotors,

calipers, and master cylinders. The rotors will be purchased, however, the rotors must be

altered to lighten the vehicle’s overall weight.      This will be achieved by drilling

lightening holes throughout the rotor. Again, this will require the use of a drill press in

the machine shop. Therefore, scheduling will be very important to be sure that the project

schedule is met. Once the parts are ordered and received, all of the work will be

performed. Testing of the brakes will be performed when the vehicle is completed. The

group is anticipating a problem with the current hub assembly, but will not be sure until

the new rims are ordered.



Engine Mount:

       As part of the SAE competition, all vehicles must have a hitch mount. This hitch

mount will be used in a tractor pull event. During the first semester of this project, the

design team calculated the location of the hitch mount that will provide the greatest

tractive effort in this competition. The team also designed the hitch mount to make sure

it can withstand the applied forces during the competition.
Vehicle Aesthetics:

       The design team will also upgrade the overall aesthetics of the vehicle. This will

be accomplished with new sheet metal for the belly pan and body panels. These will be

painted along with the entire structure to enhance the vehicle’s look. New tires will be

placed on the Baja and the Stevens logo, and the logos of our various sponsors will be

fixed to the vehicle.

Safety Features:

       The SAE Mini-Baja competition requires safety features on the vehicle to protect

the driver. A majority of the safety requirements on the existing vehicle are still up to

SAE regulations, these features will not be repaired for competition. This semester the

following will be repaired or added; a kill switch, a fire extinguisher, padding around the

roll cage, belly pan, and a pull start, located above the driver, for the engine.

       The roll cage on the vehicle is important because it is the protection for the driver

during the race. This is where most of the safety features will be fastened. The existing

kill switch will be tested to ensure that it is capable of shutting down the engine in case of

an emergency. It is suspected that the current switch shorts out. In the roll cage, padding

and arm restraints will be added in order to protect the driver should the vehicle roll over.

A fire extinguisher will mounted in the cage, easily accessible to both the driver and crew

members.

       During the race, if the vehicle stalls the driver is not permitted to exit the vehicle

to restart the engine. Thus, SAE requires that an overhead pull start cord be added in

order to allow the driver to safely restart the baja. Finally, a belly pan will be bolted to

the underside of the cage to protect the driver during the race from underbrush.
                                       Project Schedule

          The scheduling of this project entails a detailed statement of each task to be

perform by the design team. These tasks are linked to those on the schedule’s Gantt

Chart. The tasks to be accomplished in this project are explained below.

     Project Organization and Design Review - This task involved the review of the

      design project as a continuation of ME 415. All group members and the project

      advisor, reviewed the completed design and planned the steps to construct and

      complete this project.

     Finalize Design/Drawings - This task will involve finalizing the designs presented

      ME 415 while incorporating any feedback by the Project Review Panel. All drawings

      will be finalized and approved, will then be sent to the Stevens Machine Shop for

      fabrication.

     Order Materials/Parts - Per the design presented in ME 415, the group will need to

      order the necessary materials for fabrications and standardized parts.

     Disassemble Baja - The design incorporates a new suspension system, braking

system

      and hitch mount. The previous designs of these components will be removed from

the

      existing Baja, and the Baja will be prepped for assembly of the new designs.

     Report for SAE Competition - For the SAE Mid West Mini Baja competition, a full

      design report must be presented to the SAE Review prior to the competition. This

      report will be graded     and count for the overall score of the vehicle during

competition.
   Machine Parts - This design will need the fabrication of several parts for the new

    designs, the design team estimates approximately 15 hours of machining time.

   Assembly - Once all the ordered parts and machined parts are ready, the new

    components will be assemble onto the Baja.           Those safety features needing

    maintenance will be addressed and the overall aesthetics of the vehicle will be

    improved.

   Testing and Tweaking - This will be the period prior to the competition that the

    team will evaluate the performance of the vehicle. This will be accomplished by

    simulating the events the Baja will compete in. These tests will lead to any changes

    that might be necessary to upgrade the performance of the vehicle.
                                  Budget and Resources

        The project that is being proposed for the spring semester is going to cost some

money. These costs are going to be compiled from materials, labor, competition fee, and

traveling expenses. The numbers are calculated using the following rates:

   Labor costs based on $20/hr for each Junior Engineer and Technician

   Overhead rate for all labor costs at 100 %

   Machine Shop time at $35/hr

   Computer Lease at $3.13/ hr

        The project materials costs to complete the vehicle in order to meet all Society of

Automotive Engineer’s safety requirements were calculated in the list below.

                     Materials Cost List
Material                 Cost         Quantity Total Cost
Engine(entrance fee)        $ 150.00     1       $ 150.00
Differential                $ 100.00     1       $ 100.00
Master Cylinder             $ 31.00      2        $   62.00
Brake Tubing                $ 10.00      1        $   10.00
Brake Rotor                 $ 30.00      4       $ 120.00
Steel Stock(1/2x4x18)       $ 56.21      1        $   56.21
Steel Stock(1/2x6x9)        $ 75.00      1        $   75.00
Steel Beam(1/2x1/2x14)      $ 25.00      1        $   25.00
Steel Stock(1/4x4x18)       $ 32.30      1        $   32.30
Suspension Components       $ 400.00     1       $ 400.00
Fire Extinguisher           $ 30.00      1        $   30.00
Fasteners                   $ 75.00      1        $   75.00
Miscellaneous               $ 100.00     1       $ 100.00

Total Materials Cost                             $ 1,235.51



Applied to some of these materials costs is an assembly labor cost. This entails the either

the manufacturing of the material or the assembly of the materials to the existing Mini-

Baja vehicle. The labor costs have been calculated and categorized in the chart below.
              Labor Costs for Construction
                       Hours        Rate   Total
Junior Engineer Design         20 $20/hr     $ 400.00
Machine Shop                   15 $35/hr     $ 525.00
Assembly Time                  20   $8/hr    $ 160.00

Total Labor Costs                                $ 1,085.00



Next, the project cost also includes travel expenses for the team to travel to Milwaukee

for the Automotive Society of Engineers Midwest Mini-Baja Competition from June 12

to June 14. This cost would include a 2 hotel rooms for 4 nights, and travel expenses.

The travel distance would be approximately 1800 miles round-trip. Therefore, the travel

expenses would be for 1800 miles at 0.31 cents/mile. Also included in the travel

expenses would be for a U-Haul trailer for the vehicle and supplies. Finally, the team

members are also requesting a food reimbursement of $15/day for each member. Below

is a summarized chart of the project travel expenses.

                        Travel Expenses
                        Quantit Price           Nights/ Total
                          y                     miles
Hotel Room                 2    $50/night          4      $ 400.00
Vehicle                    1    .31cents/mile    1800     $ 558.00
Reimbursement
Trailer Rental             1    $25/day            5      $ 125.00
Food Expenses              4    $15/day            5      $ 300.00

Total Travel Expenses                                    $1,383.00



The total project cost is calculated in the chart below. There is a project overhead which

is taken to be 100 percent of the direct labor costs.
    Spring Semester Total Project Costs

Materials                         $   1,235.51
Labor                             $   1,085.00
Travel                            $   1,383.00
Overhead                          $   1,383.00

Total Project Costs               $ 5,086.51



As seen above, the total project cost is approximately equal to $5,087. However, the

actual cost to build the machine would only be for the materials, $1,235.51. In order to

compete in Milwaukee, an additional $1,383 is needed for travel expenses.
                                       Conclusion

       In conclusion, the team feels that this project will allow the team to experience

real world engineering.    Dealing with time restrictions, machine shops, and vendor

delays, these are all daily aspects of a Mechanical Engineering career. Learning how to

be a hands-on engineer can not be taught in the class room, it is an acquired skill. The

team feels that applying acquired knowledge to this project will result in a highly

competitive machine. A machine that will provide Stevens Institute of Technology with

tangible piece of equipment which exemplifies a Stevens Education.

       The team will deliver a finalized Mini-Baja vehicle which will be entered in the

Society of Automotive Engineers Midwest Mini-Baja Competition in Milwaukee. Along

with the vehicle, the design group will provide full engineering and assembly drawings.

The team will submit a complete design report to the SAE for the competition and a final

design report for the second phase of the two semester design project. The next step is to

provide Stevens Institute of Technology with a trophy from the competition.