An apparatus and method for the non-contact measurement of tensile loading (or tension) in ferromagnetic materials, particularly wire ropes, cables, and strands. The magnetostrictive effect is used to measure wave propagation properties within such materials to determine load forces imposed on the tested material based upon a signature obtained for like materials under like conditions. The apparatus and method contemplate an active measurement application, wherein a transmitting sensor generates an mechanical pulse within a material through the magnetostrictive effect, and a receiving sensor detects reflected mechanical waves within the material by the inverse magnetostrictive effect. Unlike other sensing methods, utilizing the magnetostrictive effect in this way has the advantage of generating and detecting mechanical waves in the tested material without direct physical or acoustical contact. The apparatus and method of the present invention also anticipates the use of a long-term monitoring system that records acquired tensile load measurements for detection of possible structural anomalies and immediate activation of an alarm, or storage and retrieval/analysis at a later time.
Hegeon Kwun; Keith Bartels; John J. Hanley