1 / 29

GRAVITATIONALFORCES

GRAVITATIONALFORCES. “G”. The measure of gravity acting on a object. The normal force which acts on all bodies is equal to 1 G. During freefall, an object will fall at 32.2 fps 2 terminal velocity is reached. ACCELERATION. Change in velocity in either magnitude or direction

azalia-lawrence
Download Presentation

GRAVITATIONALFORCES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. GRAVITATIONALFORCES

  2. “G” • The measure of gravity acting on a object. • The normal force which acts on all bodies is equal to 1 G. • During freefall, an object will fall at 32.2 fps2 terminal velocity is reached

  3. ACCELERATION Change in velocity in either magnitude or direction • The most common accelerative force is gravity DECELERATION Any reduction in the velocity of a moving body

  4. INERTIAL FORCE • The resistance to a change in the state of rest or motion • A body at rest tends to stay at rest, a body in motion tends to stay in motion

  5. TRI-AXIAL REFERENCE SYSTEM

  6. FACTORS AFFECTINGACCELERATIVE FORCES • Intensity • Duration • Rate of onset • Body area and site • Impact direction

  7. PHYSIOLOGICAL EFFECTS OF LOW MAGNITUDEACCELERATION

  8. +Gz Forces Head to Foot

  9. FACTORS MODIFYING +GZ

  10. DECREMENTAL FACTORS Any factor that reduces overall efficiency of the body, especially the circulatory system • Blood volume decrease - varicose veins - hemorrhage • Blood pressure decrease - hypotension - fatigue/illness - alcohol abuse

  11. INCREMENTAL FACTORS Any factor that increases overall efficiency of the body, especially the circulatory system • Hypertension • Fear & excitement • Tensing of muscles • Short stocky build • L-1 Maneuver

  12. L-1 MANEUVER Procedure: • Remain upright • Tense muscles • Exhale against a closed glottis at 2 to 3 second intervals Note: Increases G-load tolerance by 4 Disadvantages: • Physically Exhausting

  13. -Gz Forces Foot to Head

  14. +/- Gx FORCES Mild transverse accelerations / decelerations during landing and taking off

  15. TRANSVERSE “G” TOLERANCE • +Gx 15 G’s 5 seconds • -Gx 12 G’s 5 seconds

  16. +/- Gy FORCES • Human body has minimal tolerance to right or left accelerations • Most aircraft do not apply accelerative forces in the lateral direction

  17. PHYSIOLOGICAL EFFECTS OF HIGH MAGNITUDE ACCELERATION AND DECELERATION

  18. EFFECTS • Minor discomfort • Incapacitating • Minor injury • Irreversible injury • Lethal

  19. SOURCES • Aircraft crashes • Ejection seats

  20. G’s (Seconds)

  21. AIRCREWMEMBER SURVIVABILITY DURING THE CRASH SEQUENCE

  22. CRASH SURVIVABILITY CRITERIA • Amount of decelerative forces transmitted to the body • Occupiable living space

  23. Human Tolerance Limits to Whole Body Impact -16 Gs (0.1 second duration) -Gz -40 Gs +9 Gs -Gx +Gy +Gx - Gy +80 Gs -9 Gs +Gz +20 Gs

  24. AIRCRAFT DESIGN FEATURES • (CREEP)! • Container • Restraint system • Environment • Energy absorption • Post crash protection

  25. QUESTIONS?

More Related