8/15/2019 Ladder Frame

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Group_1 Ladder Frame MAPE

-Manufacturing Technologies in Automotive Industry

Definition: A type of frame design which has two long parallel sections which run from the front to the

rear of the vehicle. In various places there are shorter sections which connect the long sections. The

result looks like a ladder. (Source: Automotive Dictionary)

Basic Properties: 

1)  Resembles a ladder and is one of the oldest and simplest designs.

2) 

The frame assembly includes a pair of lengthwise parallel side rails and a number oftransverse cross members interconnecting the side rails at spaced positions. 

3) 

The frame assembly acts as the main load carrying member for rigidity and strength 

4)  Generally used in the field of motor vehicles, especially off road vehicles, pick-up trucks and

similar vehicles. 

Distinction with other design Concepts:

1) 

Offers good beam resistance because of continuous rails from front to rear as opposed to

tubular space frame construction which is strong in all directions.

2)  Poor torsional resistance as compared to tubular frame or metal shell construction

3)  Heavy construction as compared to other concepts leading to high inertial losses and poor

fuel economy

Different sub-concepts: C-shape-Most common types used and made by roll forming

Hat shape-It is not commonly used due to weakness and propensity of rust

Boxed shape-Are made by welding to matching C rails

Advantages:

1. 

Stronger, Cheap, easy design, more durable

2.  Design flexibility of body

3.  It has more resistance for long-term fatigue and impact

4.  Due to his modular nature a body on frame is easy to repair and replace parts

5.  Quieter- vehicle with ladder frame is quieter as stress is do not pass into the body, which is

isolated from the frame with rubber pads.

Disadvantages:1.  Heavier than others frames

2.  Low Stiffness and high fuel consumption

3.  Less torsional resistance

4. 

It’s weaker as the torsional rigidity is very low especially when the frame deals with vertical

loads or bumps.

Used Materials: Wood(First used material),Steel(standard material)

Used Manufacturing Technologies: Die Casting, Extrusion

Usage of the concept:

Models:

  Asian and African markets: India, Australia, UK, Japan, Thailand

 

Toyota currently manufactures the most body-on-frame SUVs with the Runner, FJCruiser, Land Cruiser and Sequoia

  Nissan with the Armada, Patrol and X terra, Tata safari, xenon pick up, Mahindra Scorpio,

XUV, Thar

  American markets: Jeep Wrangler, Ford expedition, Cadillac Escalade

  European markets: Mercedes Benz G class

  Most of the load carriers (semi, mid and heavy payload trucks) have body on frame concept.

Future of the concept:

  Currently most SUV manufacturers have departed from the usual ladder on frame structure

except for Toyota.

  Very prominent in heavy duty trucks and load carriers.

 

Electric cars like BMW i3 have body on frame to integrate batteries in frame and separate the

passenger compartment.(Reference: Wikipedia, SAE forum, top gear)