Automobile MaterialsAutomobile Materials

Prof. Nitin MalviyaProf. Nitin Malviya(Associate Professor)(Associate Professor)

Sagar Institute of Science & Technology, Bhopal Sagar Institute of Science & Technology, Bhopal

Some Background...Some Background...Cars at first were built entirely of wood, and later Cars at first were built entirely of wood, and later of wood frames with steel body panels.of wood frames with steel body panels.

In the early 1900’s, the idea of a body-on-frame In the early 1900’s, the idea of a body-on-frame design came about.design came about.

These vehicles hadThese vehicles hada load-bearing chassisa load-bearing chassisthat supported all thethat supported all themechanical partsmechanical partsand a body usual madeand a body usual madeof steel.of steel.

Moving Forward...Moving Forward...

Heavy-duty vehicles like trucks and busses still Heavy-duty vehicles like trucks and busses still use the idea of body-on-frame.use the idea of body-on-frame.

Regardless of the construction technique, steel Regardless of the construction technique, steel is still the predominant material used in is still the predominant material used in automotive frames.automotive frames.

Today, most smaller Today, most smaller vehicles such as small vehicles such as small SUV’s and sedans use a SUV’s and sedans use a unibody (or unibody (or monocoque) monocoque) construction.construction.

A Quick ComparisonA Quick Comparison

MonocoquesMonocoques

Typical Ladder FrameTypical Ladder Frame

What it’s all AboutWhat it’s all About

Today, the new revolution in car design is the Today, the new revolution in car design is the use of new materials in the vehicle structure.use of new materials in the vehicle structure.

As fuel economy restrictions become tighter, As fuel economy restrictions become tighter, manufacturers must find new ways to meet manufacturers must find new ways to meet them.them.

This has led them away from using so much This has led them away from using so much steel in the vehicles, and more and more are steel in the vehicles, and more and more are moving towards aluminum.moving towards aluminum.

A Basic ComparisonA Basic ComparisonTwo common alloys used in car manufacturing:Two common alloys used in car manufacturing:

For Aluminum: AA 5182For Aluminum: AA 5182

For Steel: AISI 1020For Steel: AISI 1020

SteelSteel AlAl

Yield Yield StrengthStrength

(MPa)(MPa)294.8294.8 395395

UTS (MPa)UTS (MPa) 394.7394.7 420420

Hardness Hardness (HB500)(HB500) 104104 5858

PropertiesProperties

Density of Steel: 7.88 g/cm3Density of Steel: 7.88 g/cm3

Density of Aluminum: 2.7 g/cm3Density of Aluminum: 2.7 g/cm3

Aluminum is about 3 times lighter than steel per Aluminum is about 3 times lighter than steel per unit volume, but can be made just as strong unit volume, but can be made just as strong using certain alloys/shapes/bonding methods.using certain alloys/shapes/bonding methods.

Because of this, AL parts can be thicker, and Because of this, AL parts can be thicker, and thus stronger, than their steel counterparts, all thus stronger, than their steel counterparts, all while weighing less.while weighing less.

The Move to AluminumThe Move to AluminumThe first production vehicle to move to an Al The first production vehicle to move to an Al frame was the Audi A8 in 1994.frame was the Audi A8 in 1994.

This allowed Audi to make their full-size car This allowed Audi to make their full-size car lighter than the competitions (BMW, lighter than the competitions (BMW, Mercedes,Lexus...), thus giving them the edge Mercedes,Lexus...), thus giving them the edge in performance & handling.in performance & handling.

This comes at a price premium though, for This comes at a price premium though, for instance compared to a Lexus LS460 (Steel instance compared to a Lexus LS460 (Steel framed) which costs around $65,000. The A8 framed) which costs around $65,000. The A8 starts at $75,000starts at $75,000

Audi A8Audi A8

Lexus LS460Lexus LS460

Cars Utilizing Al FramesCars Utilizing Al Frames

SafetySafetyNot too many safety tests have been Not too many safety tests have been performed on Al framed vehicles due to their performed on Al framed vehicles due to their usually higher price.usually higher price.

However, the Audi A2 is an inexpensive However, the Audi A2 is an inexpensive compact car that has been tested, and compact car that has been tested, and received overall favorable reviews compared to received overall favorable reviews compared to its steel bodies counterparts.its steel bodies counterparts.

Some other Some other advantages...advantages...There are some manufacturing There are some manufacturing methods that can only be done methods that can only be done with aluminum, such as with aluminum, such as extrusions.extrusions.

These extrusions allows the Al These extrusions allows the Al Space Frame to have about half Space Frame to have about half the amount of parts as a the amount of parts as a traditional steel monocoque.traditional steel monocoque.

Because of all this, Al is already a Because of all this, Al is already a cheaper material to use for low cheaper material to use for low volume production cars (under volume production cars (under 100,000 units a year or so).100,000 units a year or so).

A Few Other Facts...A Few Other Facts...

Today, the average car contains about 200 Today, the average car contains about 200 pounds of aluminum parts.pounds of aluminum parts.

Aluminum space frames (like that from Audi), Aluminum space frames (like that from Audi), contain fewer parts and fewer connection contain fewer parts and fewer connection nodes, which helps keep production costs nodes, which helps keep production costs lower.lower.

In The FutureIn The FutureWhile Aluminum may be the wave of the future While Aluminum may be the wave of the future for now, some exotic car companies are for now, some exotic car companies are already looking ahead to composite materials.already looking ahead to composite materials.

Take for example Porsche Carrera GT, which Take for example Porsche Carrera GT, which used a completely Carbon-Fiber monocoque used a completely Carbon-Fiber monocoque construction in addition to Carbon-Fiber body construction in addition to Carbon-Fiber body panels.panels.

Because of this, the curb weight of the car was Because of this, the curb weight of the car was only 3000 lbs., even with a 5.7L V-10 engine only 3000 lbs., even with a 5.7L V-10 engine powering it.powering it.

Other Other materials materials Carbon fiberCarbon fiberCarbon-fiber-reinforced Carbon-fiber-reinforced polymerpolymer, , carbon-fiber-reinforced carbon-fiber-reinforced plasticplastic or or carbon-fiber reinforced carbon-fiber reinforced thermoplasticthermoplastic ( (CFRPCFRP, , CRPCRP, , CFRTPCFRTP or or often simply often simply carbon fibercarbon fiber, or even , or even carboncarbon), ), is an extremely strong and light fiber-reinforced is an extremely strong and light fiber-reinforced polymer which contains carbon fibers.polymer which contains carbon fibers.

Many supercars over the past few decades Many supercars over the past few decades have incorporated CFRP extensively in their have incorporated CFRP extensively in their manufacture, using it for their monocoque manufacture, using it for their monocoque chassis as well as other components.chassis as well as other components.

Honeycomb structure made of carbon-fiber-Honeycomb structure made of carbon-fiber-reinforced polymer on a BMW i3reinforced polymer on a BMW i3

Tempered glassTempered glassTempered glass is created by heating and Tempered glass is created by heating and then rapidly cooling the glass to room then rapidly cooling the glass to room temperature by ushering it through a system temperature by ushering it through a system of blowers.of blowers.

This type of glass is used for the This type of glass is used for the surrounding windows of car (also called the surrounding windows of car (also called the sidelitessidelites) and the back window (or ) and the back window (or backlitebacklite).).

Breaks in to granules during impact.Breaks in to granules during impact.

Laminated glassLaminated glass is a type of safety is a type of safety glass that holds together when shattered. glass that holds together when shattered. In the event of breaking, it is held in place In the event of breaking, it is held in place by an interlayer, typically of polyvinyl by an interlayer, typically of polyvinyl butyral(PVB), between its two or more butyral(PVB), between its two or more layers of glass. layers of glass.