1. Mechanical Energy and Vehicle Anatomy3
Mechanical Energy and Vehicle Anatomy

2. Knowledge Objectives (1 of 2)
Discuss the three concepts of energy that are typically associated with injury.
Describe the three collisions that occur during every motor vehicle collision.
Explain the motor vehicle collision area of impact classifications.
Describe the inner and outer components that make up a vehicle system.

3. Knowledge Objectives (2 of 2)
Discuss the various methods used to power vehicles.
Explain the various types of steel designations.
Describe the three forms of frame systems.
Describe the various types of vehicle glass.

4. Introduction An integral part of the extrication process:
The application of energy in relation to a motor vehicle collision
The anatomical parts of a vehicle system

5. Energy (1 of 6) Energy is transferred between parts of a system.
Capacity for doing work
Law of Conservation of Energy: Energy can be neither created nor destroyed.
Mechanical energy is the force behind vehicle collisions.

6. Energy (2 of 6) Two types of energy Kinetic energy—energy of motion
Based on weight and velocity
Kinetic energy=mass/2 x velocity2
Potential energy—the energy of position or stored energy

7. Energy (3 of 6) Work is a mechanism for the transfer of energy.
Energy is transferred to an object and the object is displaced.
Applied in two ways:
Positive–in the direction of travel
Negative–against the direction of travel

8. Energy (4 of 6) Work can be extreme or lessened by:
Stored potential energy
Speed of travel
Weight of vehicles
Whether brakes are used
Vehicle construction
Courtesy of Mark Woolcock

9. Energy (5 of 6) Newton’s First Law of Motion:
Objects at rest stay at rest
Objects in motion stay in motion unless acted upon by an outside force.
Traumatic injury occurs when the body’s tissues are exposed to energy levels beyond their tolerance.

10. Energy (6 of 6)
Mechanism of injury (MOI) describes the forces acting on the human body that cause injury.
The same release of energy that occurs during a vehicle collision occurs in the human body.
The human body will experience a positive and negative work force.

11. Vehicular Collision Classifications (1 of 9)
Collisions are classified by initial impact.
Front impact
Lateral impact
Rear-end
Rollovers
Rotational (spins)
Vehicle collisions consists of three collisions.

12. Vehicular Collision Classifications (2 of 9)
Vehicle impact with object
Damage to the vehicle can give clues about severity of the accident and occupant injuries.
© Jack Dagley Photgraphy/ShutterStock, Inc.

13. Vehicular Collision Classifications (3 of 9)
Occupant impact with vehicle
Energy of the passenger’s mass and velocity is converted into the work of stopping the body
Reduced if passenger is wearing a seatbelt or airbag is deployed
Injuries may be immediately apparent

14. Vehicular Collision Classifications (4 of 9)
Occupant organs impact solid structures of the body
Organs can impact back and forth several times.
Injuries may not be obvious, but they can be life-threatening.
Initial impression can help direct lifesaving care.

15. Vehicular Collision Classifications (5 of 9)
Front impact collisions
Vehicle strikes an object head-on.
Vehicle travels under object
Vehicle travels over object
MOI should consider the restraint systems.

16. Vehicular Collision Classifications (6 of 9)
Rear–end collisions
Cause whiplash injuries
May also cause acceleration-type injury to the brain
© Crystalcraig/Dreamstime.com

17. Vehicular Collision Classifications (7 of 9)
Lateral (side–impact) collisions
Limited protection for occupants
High level of fatalities
Lateral whiplash injuries
© Sylvie Bouchard/ShutterStock, Inc.

18. Vehicular Collision Classifications (8 of 9)
Rollovers
Large trucks and SUVs most prone
Injuries vary depending on use of restraints.
Ejection is common, life-threatening injury
Courtesy of Darian Russo, North Lauderdale Fire Rescue

19. Vehicular Collision Classifications (9 of 9)
Rotational collisions
Conceptually similar to rollovers
Rotation may cause secondary impacts

20. The Vehicle System The rescuer should:
Understand the inner and outer components of a vehicle system.
Know the basic parts that make up various vehicles.
Not improvise!

21. Vehicle Classifications (1 of 3)
DOT classifies vehicles based on whether the vehicle transports passengers or commodities.
Passenger vehicles: manufactured for the purpose of transporting passengers
DOE classifies vehicles by size in cubic feet (passenger and cargo) and gross weight.

22. Vehicle Classifications (2 of 3)

23. Vehicle Classifications (3 of 3)
Vehicle identification number (VIN)
17-character sequence of letters and numbers
All vehicles manufactured in the United States and many other countries are required to have them.
Normally etched on a plate
Each alphanumeric designation has a specific meaning.

24. Vehicle Propulsion Systems (1 of 3)
Conventional-type vehicles
Use internal combustion engines (ICE) for power
Burn petroleum-based fuels and alternative fuels
Fuel tanks are constructed of steel or aluminum
Pounds per square inch (psi) describes pressure
Amount of pressure exerted over an area of equaling one square inch

25. Vehicle Propulsion Systems (2 of 3)
Hybrid vehicles
Combine two or more power sources for propulsion
Usually a high-voltage electrical system and an internal combustion engine
Hydrogen fuel cell vehicles
Electrochemical devices that use hydrogen and oxygen to create electricity

26. Vehicle Propulsion Systems (3 of 3)
Electric-powered vehicles
Use an electric motor for propulsion
Powered by batteries in a rechargeable battery pack
Recharge through dedicated charging station or plug-in house current

27. Electricity (1 of 3)
Most ICEs use a basic 12-volt lead acid battery for starting and powering electrical components.
Hybrids, fuel cells, and electric vehicles also use a 12-volt lead acid battery.
Advanced electrical design

28. Electricity (2 of 3) Some vehicles use more than one 12-volt battery.
A 12-volt lead acid battery system consists of six cells in an electrolyte solution.
Chemical reaction with lead plates
Produces electrons that flow through conductors
When overcharged without proper venting, an explosive by-product can be generated.

29. Electricity (3 of 3) Other main sources of power: Alternator
Belt-driven generator
Produces current used to operate electrical components
Voltage regulator
Regulates the flow of electricity from the alternator

30. Steel (1 of 3)
Manufacturers are always working to make their vehicles more fuel efficient, lighter, stronger, and crash-resistant.
Ideas come from the racecar industry.
“Safety cage”—protects occupants from rollovers and other impacts
Conventional vehicle designs are becoming obsolete.

31. Steel (2 of 3)
Steel is measured by tensile strength and yield strength.
Tensile strength measures the amount of strength required to tear a section of steel apart.
Yield strength is the amount of force or stress that a section of steel can stand before permanent deformation occurs.

32. Steel (3 of 3) Alloyed steels—mixture of metals and elements.
World Steel Association classifications:
High Strength Steel (HSS) –tensile strength of 39 to 102 ksi
Ultra High Strength Steel (UHSS) –tensile strength of 102 ksi or greater
Advanced High Strength Steel –minimum tensile strength of 73 ksi to 116 ksi

33. Frame Systems (1 of 4) Body–over–frame construction
Body is placed onto a frame skeleton.
Ladder frame
Used for heavier vehicles
Force distribution is greater on the occupants

34. Frame Systems (2 of 4) Unibody construction One piece
No formal frame structure
Body is merged with chassis.

35. Frame Systems (3 of 4) Unibody construction (cont’d)
Incorporates crumple zones
Potential to be split in half in a severe collision

36. Frame Systems (4 of 4) Space frame construction
Designed for the auto racing industry
High price keeps it from being mass-produced
Can be driven in its skeleton form

37. Vehicle Anatomy and Structural Components (1 of 13)
Bumper system
Helps vehicle withstand impact of a collision
Federal regulations require that a bumper be able to withstand front or rear impact collision at 2.5 mph
Several different types of bumper systems

38. Vehicle Anatomy and Structural Components (2 of 13)
Upper rail
Located on front top section of the vehicle
Two beams hold the hood in place and attach the front wheel strut system to the chassis

39. Vehicle Anatomy and Structural Components (3 of 13)
Strut tower
Component of the suspension system
Dash bar
Steel bar that runs the entire width of the car.
Dash brackets are located in the center console.

40. Vehicle Anatomy and Structural Components (4 of 13)
Rocker panel
Channel that runs along the outermost sections of the floorboard where the doors rest.
Hollow section of metal
Little structural support

41. Vehicle Anatomy and Structural Components (5 of 13)
Key components of a door
Door hinges—allows doors to swing
Hinges come in various types
Leaf system
Full body hinge

42. Vehicle Anatomy and Structural Components (6 of 13)
Key components of a door (cont’d)
Swing bar assists the door in opening and closing.

43. Vehicle Anatomy and Structural Components (7 of 13)
Key components of a door (cont’d)
Latching mechanisms
Nader bolt—difficult to cut through
U-bolt—easier to cut through.

44. Vehicle Anatomy and Structural Components (8 of 13)
Key components of a door (cont’d)
Impact beam
Entire length of the door
Absorbs impact energy of another vehicle or object.

45. Vehicle Anatomy and Structural Components (9 of 13)
Roof Posts add vertical support to the roof.
A-post
Closest to windshield
Layers of steel or aluminum
Expose and examine for SRS.

46. Vehicle Anatomy and Structural Components (10 of 13)
B-post
Located between front and rear doors
Standard seat belt harness includes a shoulder and lap belt.
Pretensioner belt system pulls back and tightens when activated by a collision.

47. Vehicle Anatomy and Structural Components (11 of 13)
B-post (cont’d)
Automatic seat belt system uses a shoulder harness that slides into place automatically.
Areas may be reinforced with HSS.

48. Vehicle Anatomy and Structural Components (12 of 13)
C-post
Rear post in most vehicles
Can be wide or narrow
Air bag cylinders may be present

49. Vehicle Anatomy and Structural Components (13 of 13)
Piston struts
Assist in lifting and support of vehicle components
Locations vary.
Cutting the cylinder section can cause a rapid release of pressure or hydraulic fluid.
Vehicle fires are a concern.

50. Vehicle Glass (1 of 4) Laminated safety glass
Created by heating a layer of clear plastic film between two layers of plate glass.
Prevents the glass from flying in on the occupant.
Window spidering is caused when an object breaks it.

51. Vehicle Glass (2 of 4) Tempered safety glass
Glass is heated and then quickly cooled
Breaks into small pieces with no long shards (dicing)

52. Vehicle Glass (3 of 4) Enhanced protected glass (EPG) Polycarbonate
Uses both the laminating and tempering process
Used on side and rear windows
Polycarbonate
Clear plastic material that can endure impacts
Pliable on impact
More and more manufacturers now use it

53. Vehicle Glass (4 of 4) Ballistic glass Bullet-resistant glass
Weight and thickness depends on level of protection
Not advised to remove or cut into this material.

54. Summary (1 of 3)
Three concepts of energy are associated with injury: potential energy, kinetic energy, and work.
Motor vehicle collisions are classified by the area of initial impact.
Every motor vehicle collision is actually three collisions.
A rescuer must understand the inner and outer components of a vehicle system before attempting a rescue.

55. Summary (2 of 3)
The Department of Transportation (DOT) classifies vehicles based on whether they transport passengers or commodities.
The Department of Energy (DOE) classifies vehicles by size and gross weight.
Most vehicles on the road today are conventional-type vehicles, using an internal combustion engine (ICE) for power.

56. Summary (3 of 3)
The development of strong, crash-resistant vehicles requires engineers and the steel industry to develop stronger and lighter steels.
Two types of frame systems (body-over-frame and unibody) are most common in today’s vehicles.
Several key components make up the body of the vehicle.
The technical rescuer can encounter several different types of glass in a vehicle.