The load distribution has more effect on reliability than the distribution of strength. Although much unreliability is due to variations in the product giving rise to weak components, load distributions can be very wide, mean strength is usually considerably greater than mean load. The author discusses the way in which failure can occur when an abnormally high load is applied to an abnormally weak component. An example is given where, on gear changing, an engine experienced a torque 2 1/2 times its rated value. The problem is expressed mathematically in the form of a joint probability. Rectangular distributions are used with tails to illustrate the possible effects of various combinations of load and strength. Variations of failure rate can occur with age depending upon the way in which the load is applied. Examples are given to show high failure rates with rough handling. It is seldom possible to estimate the failure rate of an item when it is transferred from one environment to another. If its environment is restricted, failures occur mostly in the early life. The author suggests that before parallel redundancy can be used successfully, the environment must be controlled. (TRRL)

  • Corporate Authors:

    Modino Press Limited

    50 Pine Grove
    London N2O 8LA,   England 
  • Authors:
    • Carter, ADS
  • Publication Date: 1980-6

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00324792
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Aug 15 1981 12:00AM