DESIGN sTaTeMeNt UnLeAsHeD !!!

Finally the design process is here. After a gruelling round of drawings, analysis and ‘debates’ we present before you the design process which we will be adopting in our endeavour towards the accomplishment of our AMPHIBIOUS VEHICLE.

NOTE: we have used some technical terms (hull,etc.) in this article which may cause some interpretation problems for non-technicians. This is intentional as we want the reader to search out these terms and experience the joy of learning through self discovery.

1. Engine Transmission: The engine to be incorporated in our vehicle is a Honda Street 100 engine. It is a 4 stroke engine with single cylinder and specifications as 97.2 cc, 6 bhp and a maximum rotational speed of 7500 rpm. The engine is fitted with an automatic centrifugal clutch with four forward speed. This engine will be used to provide a rear axle drive with the help of a chain and sprocket mechanism.

2. Steering System: Considering the vehicle weight, size, shape and driving conditions, we came up with the plan of using a steering which includes a Pitman arm with two tie rod ends. This mechanism will be a 100% Ackerman mechanism with an Ackerman angle of 24 degrees. If we consider a turning radius of 3 metres, then the rod ends travel is of 5 inches.

3. Braking System: We will be using Disc Brakes in our vehicle. We had a choice to make between Disc brakes and Rim brakes. Though Rim brakes are cheap, light, mechanically simple, easy to maintain, and powerful, they perform poorly when the rims are wet. Rim brakes require regular maintenance. Brake pads can wear down quickly, and have to be replaced. Over longer time and use, rims become worn. Rim brakes also heat the rim because the brake functions by converting kinetic energy into thermal energy. It is not a problem in light-weight vehicles but in case of a heavy-weight vehicle and tandems in mountainous regions, the heat build-up over a long descent can increase tire pressure so much that the tire blows off the rim causing serious accidents. For this reason, disc brakes are often fitted instead of rim brakes in this situation.

4. Wheel Specifications: The engine will provide the vehicle a top speed of about 80 km/hr. As the estimated kerb weight of the vehicles is 300 kg, the wheels we came up with have a wheel base of 55.5 inches and a wheel track of 50 inches. The tyre dimensions are 26 x 1.3/8 inches.

5. Material to be used for fabrication: We have decided upon to use 1018 steel pipes to use as our material for the chassis. The outer diameter of the pipes is 1 inch with a thickness of 0.07 inch. With such specifications, the total weight of the chassis is coming out to be 8.41 kg (only the tubular frame). The yield strength of this material is close to 386 MPa and the elastic modulus is in the range of 190-210 GPa. The reason we chose this material is that it is readily available and easily weld-able with arc welding.

6. FE Analysis of the chassis: In order to get an unbreakable frame, a proper analysis was done on ANSYS for different designs of the frame considering different loads. A frontal impact of 5-G force and a side impact of 3-G force were considered. After analysis, the points of maximum stress were checked suitable numbers of cross bars were added in the design to minimise the stress. With the above specified yield strength and elastic modulus of the material, a factor of safety of about 1.8 was achieved. As you might remember, the snapshots of the ANSYS analysis was posted a couple of days back and you can easily watch them simply scrolling down your mouse button.

7. Hull design: the role of the hull is important when the vehicle is in water. Considering the total weight of the vehicle, it was found that the depth of the vehicle inside water is 0.5 metres. So, the minimum volume of water to be displaced by hull came out to be 0.3cu.metres. Taking into account the factor of safety, the hull has been designed by taking this volume as 0.6cu.metres.

8. Propeller Design: the point where the axle containing the propeller system will be fixed to the chassis, can be decided after knowing the water level as the ideal position will be the centre of the propeller coinciding with the water level. Depending on the availability of propellers as well as the type that suits our need, we plan to devise the propeller system in the most satisfying manner for the vehicle.

Thus, this is the basic framework of our design and also the road map of our process. We will be glad to answer any quarry regarding our design from anyone and at the same time, will be enlightened to incorporate suggestions and corrections into our design in pursuit of perfection.

While posting comments, you can choose to be Anonymous (to avoid the trouble of signing up) and in the dialogue box, type your name and contact (if you wish) after your comment.

Cheers!!!

CAD mOdEl...

As promised, we have come up with the initial CAD model of our work. We plan to work on this model further to enhance the features of our product.
The modeling was done on Pro E and was prepared exclusively by Sanjeev within an hour. This only makes us more determined to accomplish our goal. The design features of the project will be uploaded in a matter of days. Meanwhile, we would request you to post feedback and also contribute in our endeavour.

CHASSIS sTrEnGtH aNaLySiS on ANSYS !!!

3 g force=1652 lbf (3g is greater than required but for to be on the safer side
we choose 3g; 3g means 3 times the total weight of
the vehicle including the human weight)
1 pound force/square inch=6895 Pascal
in case of frontal impact,max stress=51863 pound force /square inch=357.59 MPa
This exceeds the yield stress of mild steel which is 250 MPa.
Hence, we provide an assembly of cross bars to further enhance the strength. After providing cross-bars, stress level reduces from 214mpa to 181.76mpa

factor of safetey from 1.16 to 1.5, which in simple terms, wow!!!
So we have virtually built the chassis and analyzed its strength and come to the conclusion that by providing adequate number of cross members at appropriate places, we can control the stress to be resisted by the frame, well below the failure stress...

wHaT iS aN aMPHICAR ???

An amphicar is a vehicle which runs on both water and land. This implies that whenever you have to cross a river you can use an amphicar to save time and money. Let me explain:
Say you live 5km away from the river and you have to cross the river to reach your destination (school/office,etc.). What you will generally do is go to the river bank by some vehicle (public/personal), wait for some steamer or motor-boat to pick you and then again move on land to finally reach your destination. You may cross a bridge across a river but tell you what, more than 70% of the bridges are built connecting two nearest points and these points are generally located on the outskirts, thus consuming some unwanted time and fuel of your vehicle, thus increasing your budget on travel.
Contrary to all these, by means of an amphibious vehicle, you can move from your courtyard to your office/school complex without any break thus saving time, money and effort. This increases your efficiency thus bringing money and time (saved quantities) and bringing all the more joy and prosperity to your life...

tHe TeAm !!!

If you think us to be nerds and bookworms who move from hostels to libraries and labs, you are not incorrect but absolutely wrong. To sum up, we are just a group of mates who do not bother to give a damn to the traditional way of submitting assignments, mugging up lab experiments and notes and believing in what the ‘herd’ does. The modus operandi of our group is to
“finish my job effectively and efficiently and immediately help my group mate to finish his.”
Let me introduce to the members of the project.
ANAND MOHAN (in charge of)
• Manufacturing activities
• Product Design analysis
• Material selection and testing
DURGESH SINGH (in charge of)
• Power transmission
• Steering system
• Drive assembly and installation
GEETANAV OJHA (in charge of)
• Feasibility analysis
• Promotion and marketing
• Sequencing and scheduling
SANJEEV GANGADHARAN (in charge of)
• Hull and float design analysis
• Analytical modeling and operations
• Chassis design
As echoed in the modus operandi statement, each activity is overlapped and hence not performed by a single person as we believe in 'we' and there is no place for 'I'. It is the wonderful chemistry between us and the humour we share on and off the shop floor that makes the team all the more vibrant and determined to work better than ever…

dEsPeRaTiOn & nEeD !!!

NECESSITY IS THE MOTHER OF ALL INVENTIONS ----- ------ ANONYMOUS

DESPERATION IS THE MOTHER OF NECESSITY ------------ nitcAMPHICAR team

nEeD !!!

We are taught at school to think globally and act locally.

Man has learnt to fly, cruise and travel in the air, on water and land, respectively without developing some supernatural powers. The efficiency of travel has also increased with the evolution of rafts to high speed submarines, from gliders to supersonic jets and from bullock carts to F1 racing cars. However, all these developments have taken in an isolated manner, that is, an efficient land racer cannot run on water or in air. The result of this is a time lag which can bring about serious consequences. Some of them are:

1) During natural calamities like floods, people depend on rescue boats to reach a safe location. A good example is the hurricane Katrina where almost all the households had personal cars but were totally helpless and waited for the arrival of the rescue boats.

2) In rural areas in a country like India, the transportation infrastructure is below standards. This leads to higher time lags and drastically reduces the productivity and efficiency. This transportation time lag triggers a chain of unwanted consequences throughout the entire process.

3) Fishermen risk their lives in the sea but depend solely on the distributors to take their products and hence are paid a very little sum compared to the retail price.

All the above and many more drawbacks can be overcome by developing a product which can synchronize the travel on land and water, on land and in the air or a combination of all these.

In a gruelling effort, we have moved forward to build a concept vehicle which can travel on both land and on water without any time lag, a product which can eliminate the time lag for travelling in two distinct media. Thus, we endeavour to build an amphicar.

In the mean time, I was introduced to this wonderful show called Topgear by one of my friends where I saw amphibious cars being built for fun. He suggested it for the project. This was the ignition that sparked on the fire within me and my friends to look into the concept with lot more sincerity and determination. Personally, the determination became the desperation. Thus we embarked on this idea and started our endeavour for a project that was untouched hitherto probably in any technical institution in India.

bEnEfItS

In due course of time, we encountered umpteen situations where an amphibious vehicle can come in handy. Some of them as of now are:

Flood rescue operations: whether it is hurricane Katrina or the devastating floods of the river Kosi, the consequences are generally aggravated by untimely rescue as there is a lag between the movement on land and water. By having a low cost amphibious vehicle, all the time delays can be avoided.

Fisherman’s chariot: often fishermen have to risk their lives in the sea and have to settle for a price much less than the market price. With a low-cost amphibious vehicle, they can access the market in a more comprehensive manner and improve their livelihood.

Personal travel: people who have to cross rivers or other water bodies for reaching their destinations like schools, offices, etc. will have no longer to wait for steamers (like me!) and thus save some precious moments of their life which can be spent with the family.

Tourist vehicle: whether it be Singapore or Amsterdam, duck tours are common and fun.

? : Shabeer Bhatia created hotmail to revolutionize the concept of e-mail and internet. It is up to you to come up with next big benefit of our project…..