FIRST QUARTERLY REPORT OF PROGRESS IN DEVELOPMENT OF SHOCK INDEX CLASSIFICATIONS FOR HIGHWAY CARGO VEHICLES

THE DEVELOPMENT OF SHOCK INDEXES IS BEING MADE TO BE USED FOR CARGO RIDE CLASSIFICATION OF HIGHWAY VEHICLES. A STATE-OF-THE-ART SURVEY OF AVAILABLE LITERATURE SHOWS THAT ALTHOUGH SOME DATA ARE AVAILABLE REGARDING THE RANGE OF ACCELERATIONS AND VIBRATION FREQUENCIES WHICH HAVE BEEN RECORDED, THE VARIOUS MEASUREMENT CRITERIA AND THE INSTRUMENTS USED IN THE MANY TESTS PERFORMED BY INDUSTRY AND MILITARY SERVICES MAKE A CORRELATION OF EXISTING DATA UNFEASIBLE. THE SOURCE OF VIBRATION TO THE CARGO OF HIGHWAY VEHICLES IS PRIMARILY THE DIRECT RESPONSE TO THE SURFACE AND SPEED OVER WHICH THE VEHICLE IS TRAVELING, AND SECONDARILY IS THE REACTIONS OF THE VARIOUS ELEMENTS OF THE VEHICLE WHICH MAY BE CAPABLE OF REDUCING OR INCREASING THE INITIAL SHOCK AND VIBRATION EFFECTS. THE FOLLOWING RIDE FACTORS ARE DISCUSSED: SUSPENSION, SPRING FRICTION, SPRUNG WEIGHT DISTRIBUTION, DYNAMIC INDEX AND WHEEL BASE, AXLE AND FRAME VIBRATION, DAMPING, WHEEL BALANCE AND RUNOUT, AND PROPELLER SHAFT. TWIST MEASUREMENTS ARE MADE OF THE PHYSICAL CHARACTERISTICS UNDER VARIOUS LOADING SCHEDULES OF TRUCKS AND TRUCK-TRAILERS, WHICH INCLUDE LIGHT AND HEAVY CARGO-CARRYING CAPACITIES. A SHORT TEST COURSE WAS SET UP TO CHECK INSTRUMENTATION, TAKE INITIAL MEASUREMENTS, AND ESTABLISH TEST PROCEDURES. THE COURSE CONSISTS OF A 300-FOOT LONG, FLAT, LEVEL, ASPHALT ROADWAY WITH THREE 4-INCH STEEL CHANNELS SPACED 50 FEET APART TO SERVE AS BUMPS TO EXCITE VEHICLE VIBRATIONS. THE CARGO CONSISTS OF STEEL PLATES AND BLOCKS TO WHICH IS SECURED A FIXTURE WITH THREE STRAIN GAGE ACCELEROMETERS SITUATED IN MUTUALLY PERPENDICULAR PLAINS CORRESPONDING TO THE LONGITUDINAL, VERTICAL, AND LATERAL AXES OF THE TRUCKS. PLATFORM-TYPE SCALES ARE USED TO DETERMINE WEIGHT DISTRIBUTION ON THE TRUCKS.

  • Supplemental Notes:
    • Rept A-3232.1, 22 PP, 2 FIG, 1 APP
  • Corporate Authors:

    General Testing Company

    ,    
  • Publication Date: 1970-1-20

Subject/Index Terms

Filing Info

  • Accession Number: 00223348
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 19 1970 12:00AM