Chains are typically used for tension load transfer. They are very flexible and allow easy length\nadjustment by hooking at the links. Steel is the traditional material for chains. Recently, synthetic\nlink chains made from ultra-strong polyethylene fibers, branded as Dyneema�®, are commercially\navailable. These chains offer a highly improved strength to weight ratio. So far, one type of such\nchains is available, and it has a Working Load Limit of 100 kN. 50 of such chains, containing 6 links\nwere tested to fracture. The strength of each chain and the location of the failed link were documented\nduring testing for later interpretation. Weibull statistics was applied in order to extrapolate\ntowards the allowable load for very low failure risks (high reliability). Two approaches were\nused. One extrapolation was based on all results; the other was applied after recognition that the\nend links failed under a slight negative influence by the connection to the testing equipment. Thus,\nin fact two populations are mixed, the chains with failing end links and the chains with failing central\nlinks. So considering the population without the failing end links is more representative for\npure chain behavior without clamping effects. The results from this latter consideration showed a\nhigher Weibull exponent, thus a more realistic extrapolation behavior. Both methods indicate that\nthe reliability at the working load limit of 100 kN is very good.
Loading....