TITLE:
Weibull Statistics Strength Investigation of Synthetic Link Chains Made from Ultra-Strong Polyethylene Fibers
AUTHORS:
Roel Marissen, Dietrich Wienke, René Homminga, Rigo Bosman, Kjell Magne Veka, Anna Huguet
KEYWORDS:
Fracture, Stiching, Fibers, Reliability, Dyneema®, Minimum Breaking Load, Working Load Limit, Extrapolation, Populations, Chain
JOURNAL NAME:
Materials Sciences and Applications,
Vol.7 No.5,
May
20,
2016
ABSTRACT: Chains are
typically used for tension load transfer. They are very flexible and allow easy
length adjustment by hooking at the links. Steel is the traditional material
for chains. Recently, synthetic link chains made from ultra-strong polyethylene
fibers, branded as Dyneema®, are commercially available. These chains offer a
highly improved strength to weight ratio. So far, one type of such chains is
available, and it has a Working Load Limit of 100 kN. 50 of such chains,
containing 6 links were tested to fracture. The strength of each chain and the
location of the failed link were documented during testing for later
interpretation. Weibull statistics was applied in order to extrapolate towards
the allowable load for very low failure risks (high reliability). Two
approaches were used. One extrapolation was based on all results; the other was
applied after recognition that the end links failed under a slight negative
influence by the connection to the testing equipment. Thus, in fact two
populations are mixed, the chains with failing end links and the chains with
failing central links. So considering the population without the failing end
links is more representative for pure chain behavior without clamping effects.
The results from this latter consideration showed a higher Weibull exponent, thus a more
realistic extrapolation behavior. Both methods indicate that the reliability at
the working load limit of 100 kN is very good.