Patent ID: 6116094
Filing Date: 2000-09-12
Classification: G01L,G01N

Abstract:
Method for determining the axial load on an elongate member for which the physical data are registered, comprising the steps ofintroducing longitudinally as well as transversely directed ultrasonic waves at one end of the elongate member under a zero-load condition and at a current temperature,measuring individually the times of flight for said longitudinally and transversely directed waves through the elongate member at said zero-load condition, and calculating from the physical data of the elongate member and from the measured times of flight of said longitudinal and transverse waves the nominal length of the elongate member,introducing longitudinal as well as transverse waves into the elongate member under the actual load condition, comparing said times of flight measured under the actual load condition with said times of flight measured under said zero-load condition, anddetermining from the difference in the wave flight times the actual load on the elongate member taking into account the influence of any occurring difference in temperature of the elongate member between said zero-load measurement occasion and the actual load measurement occasion by the equation: ##EQU9## (where v.sub.L0 is the velocity of the longitudinal waves at temperature T.sub.0,v.sub.S0 is the velocity of the transverse (shear) waves at temperature T.sub.0,K.sub.ST is the relative time of flight change for the transverse waves due to a change in temperature,K.sub.LT is the relative time of flight change for the longitudinal waves due to a change in temperature,K.sub.SL is the relative time of flight change for the transverse waves due to a change in tensile load,K.sub.LL is the relative time of flight change for the longitudinal waves due to a change in tensile load,t.sub.SL is the time of flight for the transverse waves in the actual load condition,t.sub.LL is the time of flight for the longitudinal waves in the actual load condition,l.sub.0 is the length of the elongate member in the zero-load condition at the temperature T.sub.0).