VERTICAL ACCELERATIONS MEASURED IN SEVERAL TYPES OF CAR TRAVELLING OVER SURFACE DISCONTINUITIES

To types of car were driven at several speeds and with different tyre pressures over a simulated bridge deck expansion joint. Four other tyres of car were driven at several speeds over a bumpy road. Measurements were made of peak-to-peak vertical acceleration on the car floor and at the seat-person interface. The results for all the cars used show that above a certain speed, about 30 km/h, a discontinuity will act as an impulse to the car's suspension system, since the time interval between the passage of the front and rear wheel is short. As a result at speeds above 30 km/h two resonant modes are excited--a 'body heave' at about 1.75 hz, and 'wheel hop' at 10-15 hz. Below this speed the shape of the discontinuity becomes important the effect upon the vehicle occupants of 'wheel hop' is largely filtered out by the car seat. /Author/

• Corporate Authors:

  Transport and Road Research Laboratory

  Environment Division, Old Wokingham Road
  Crowthorne RG11 6AU, Berkshire,   England 
• Authors:
  • COOPER, DRC
• Publication Date: 1973

Language

• English

Media Info

• Features: Figures; Tables;
• Pagination: 28 p.

Subject/Index Terms

• TRT Terms: Accelerometers; Pavements; Rheology; Riding qualities; Simulation; Smoothness; Stability (Mechanics); Suspension systems; Tires; Traffic speed; Vehicle characteristics; Vehicle occupants; Vibration
• Uncontrolled Terms: Speed changes
• Old TRIS Terms: Pavement smoothness; Suspension (Stability)
• ITRD Terms: 5405: Acceleration; 1243: Car; 3071: Evenness; 6997: Frequency; 6136: Measurement; 5408: Speed; 1329: Suspension (veh); 1715: Vehicle occupant; 9087: Vertical; 5558: Vibration
• Subject Areas: Highways; Passenger Transportation; Pavements; Safety and Human Factors; Vehicles and Equipment;

Filing Info

• Accession Number: 00083128
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Report/Paper Numbers: TRRL SR 12 VC Series
• Files: ITRD, TRIS
• Created Date: May 1 1975 12:00AM