Load-sharing System Research Articles

Lower tail analysis of the distribution of the strength of load-sharing systems

The Weibull distribution for the strength of a long fiber is reviewed, with emphasis on its derivation via extreme-value theory. It is shown that a corresponding Weibull distribution, but with different scale and shape parameters, is appropriate for the lower tail distribution of a bundle of parallel fibers under general load-sharing assumptions. This result is applied to series-parallel systems. The paper contains discussion of the application of these results to the strength of fibrous materials. It is concluded that the Weibull approximation, developed for series-parallel systems, is appropriate for long thin materials consisting of a small number of parallel fibers.

Limit theorems and approximations for the reliability of load-sharing systems

Techniques for studying the reliability of simple series or parallel systems are well known. This paper is concerned with more complicated systems in which the load on failed elements is transmitted to unfailed elements according to some load-sharing rule. The emphasis is onlocalload sharing, and in particular on a specific load-sharing rule introduced by Harlow and Phoenix for fibrous composites. Earlier results are reviewed and improved techniques for approximating the probability of failure and the size effect are derived.

Lower tail analysis of the distribution of the strength of load-sharing systems

The Weibull distribution for the strength of a long fiber is reviewed, with emphasis on its derivation via extreme-value theory. It is shown that a corresponding Weibull distribution, but with different scale and shape parameters, is appropriate for the lower tail distribution of a bundle of parallel fibers under general load-sharing assumptions. This result is applied to series-parallel systems. The paper contains discussion of the application of these results to the strength of fibrous materials. It is concluded that the Weibull approximation, developed for series-parallel systems, is appropriate for long thin materials consisting of a small number of parallel fibers.

Limit theorems and approximations for the reliability of load-sharing systems

Techniques for studying the reliability of simple series or parallel systems are well known. This paper is concerned with more complicated systems in which the load on failed elements is transmitted to unfailed elements according to some load-sharing rule. The emphasis is on local load sharing, and in particular on a specific load-sharing rule introduced by Harlow and Phoenix for fibrous composites. Earlier results are reviewed and improved techniques for approximating the probability of failure and the size effect are derived.

Stochastic Simulation of Wood Load-Sharing Systems

A generalized procedure was developed to predict the effect of material variability on the variability of system performance when the material properties of the system component members are correlated. This procedure utilized Monte Carlo simulations to predict the load-carrying capacity (strength behavior) of parallel-member wood load-sharing systems from a linear-elastic mathematical model also developed in this study. The simulated strength behavior obtained using this procedure was compared to the strength behavior of actual wood load-sharing systems tested to failure. This simulation technique was shown to be an extremely good predictor of system variability. Although this procedure was developed for specific application to the prediction of wood-joist floor behavior, it can easily be applied to any area of structures research in which the members exhibit correlated properties.

Availability evaluation of redundant computer systems

This paper investigates availability of two redundant computer systems, a duplex system and a load share system, under the assumptions that the failure time distribution is bivariate exponential and the repair time distribution is arbitrary. We derive the limiting availability for each system by applying a unique modification of regeneration point techniques in Markov renewal processes. In particular, the procedure for obtaining the limiting probability is presented thoroughly. This paper also gives numerical examples for comparison of the two systems from the viewpoint of the availability.